Thèses : « Forestry operation »

1

Lindroos, Ola. « Efficiency and safety in self-employed family forestry / ». Umeå : Dept. of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/2006110.pdf.

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Soler, Rafael Ribeiro. « Desempenho operacional e econômico do ensaio de uma plantadora tripla automatizada de mudas florestais / ». Botucatu, 2020. http://hdl.handle.net/11449/192922.

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Orientador: Saulo Philipe Sebastião Guerra
Resumo: O aumento da área plantada com florestas vem movimentando o setor de desenvolvimento de máquinas e equipamentos, que buscam inovar o mercado com novas soluções para a silvicultura. Sendo assim, novas alternativas surgem para a operação de plantio, com opções totalmente mecanizadas, a fim de aumentarem o rendimento e também agregarem funções em uma mesma operação. Com isso, avaliou-se uma plantadora tripla automatizada, que possui um sistema de georreferenciamento que controla sua movimentação e os locais a serem plantados. Foram mensurados os rendimentos operacionais em dois diferentes espaçamentos entre plantas, 3,5 x 1,8m e 3,5 x 2,3 m, sendo as mudas recém-plantadas avaliadas quanto à qualidade do plantio e seus espaçamentos aferidos como forma de avaliar o sistema de georreferenciamento. Após estas avaliações, realizou-se a análise econômica da operação, utilizando o modelo COST Action FP 0902. Os tratamentos adotados foram os espaçamentos entre plantas, adotando-se o delineamento inteiramente casualizado para análise dos rendimentos operacionais. Enquanto que para a análise qualitativa do plantio foram verificados a profundidade do plantio, a posição da muda em relação a cova e número de mudas por cova, bem como os espaçamentos entre plantas para cada tratamento. Considerando a análise dos rendimentos operacionais, houve diferença estatisticamente significativa entre os tratamentos para o mesmo rendimento, e também entre os rendimentos para o mesmo tratamento. Os valores... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The increase in the planted area with forests has been moving the sector for the development of machinery and equipment, which seeks to innovate the market with new solutions for forestry. Thus, new alternatives appear for the planting operation, with fully mechanized options, to accelerate the yield and also add functions in the same operation. Thereby, an automated triple planter was evaluated, which has a georeferencing system that controls its movement and the spots to be planted. Yields were measured in two different spacing between plants, 3.5 x 1.8 m and 3.5 x 2.3 m, with the newly planted seedlings were evaluated for planting quality and their spacing measured as a way to evaluate the georeferencing system. After these evaluations, an economic analysis of the operation was carried out, using the COST Action FP 0902 model. The treatments adopted were the spacing between plants, adopting a completely randomized design for the analysis of the yields. While for the qualitative analysis of the planting, the planting depth was verified, the position of the seedling in relation to the pitch and the number of seedlings per pitch, as well as the spacing between plants for each treatment. Considering the analysis of the yields, there was a statistically significant difference between treatments for the same yield, and also between yields for the same treatment. The average values calculated for the yield without refilling were 893 seedlings hour-1 and 703 seedlings hour-1 for t... (Complete abstract click electronic access below)
Doutor

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NONINI, LUCA. « ASSESSMENT OF WOOD BIOMASS AND CARBON STOCK AND EVALUATION OF MACHINERY CHAINS PERFORMANCES IN ALPINE FORESTRY CONDITIONS : AN INNOVATIVE MODELLING APPROACH ». Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/846415.

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The PhD Thesis focuses on two topics: (i) assessment of forest wood and carbon (C) stock and (ii) forestry mechanization applicable at the forest stand level for any given conditions among those found in the Italian Alpine and pre-Alpine mountainous areas. Both these topics aim to improve the use of forestry resources for climate change mitigation, starting from a bottom-up approach scaled on the information made available by Forest Management Plans (FMP). After an introduction on the topics given in chapter 1, the first topic (assessment of forest wood and C stock) is investigated in chapters 2, 3, 4 and 5, by taking the Valle Camonica District (Lombardy Region, Italy) as Case Study Area. The aim is to develop a stand-level model to estimate the mass of wood (t·yr-1 dry matter, DM) and C (t·yr-1 C) in aboveground wood biomass, belowground wood biomass and dead organic matter (i.e., deadwood and litter), quantifying, at the same time, the mass of potentially available logging residues (i.e., branches and tops; t·yr-1 DM) for energy generation and the corresponding potentially generated energy (GJ·yr-1), under the assumption that wood replaces non-renewable energy sources. Chapter 2 presents the first version of the model, called “WOody biomass and Carbon ASsessment” (WOCAS v1), aimed at the quantification of the mass of wood and C in the forest pools in a predefined reference year, by using a methodology already applied at the regional and national level. The model was tested on a dataset of 2019 public forest stands extracted from 45 FMPs (area: 37000 ha) covering the period from 1984 (year in which the oldest FMP came into force) to 2016 (most recent available data from the local FMPs). Preliminary results showed that, in 2016, the total C stock (given by the sum of C stock in aboveground wood biomass, belowground wood biomass, and dead organic matter) achieved 76.02 t·ha-1 C. The model also gives the possibility to analyze future scenarios based on the continuation of the current management practices rather than improved practices, to define a possible mitigation strategy for the activation of a local Voluntary Carbon Market. WOCAS v1 was implemented into a second version (WOCAS v2), by introducing, first of all, an improved methodology to calculate the mass of wood (t·yr-1 DM) and C (t·yr-1 C) within the forest pools from the year in which the FMPs entry into force until a predefined reference year (chapter 3). The main innovative aspect of the improved methodology is that the gross annual increment of each stand is calculated through an age-independent theoretical non-linear growth function based on the merchantable stem mass, solving the limitation of WOCAS v1 in which the gross annual increment of the stand is assumed as constant, as reported by the FMPs. This improved methodology was applied to the same dataset used for WOCAS 1 (i.e., 2019 forest stands, 45 FMPs; forest area: 37000 ha; period: 1984-2016). The total weighted average wood yield, calculated as the sum of wood yield in all the above-mentioned forest pools, ranged from 53.36±53.13 t∙ha-1∙yr-1 DM (1984) to 156.38±79.76 t∙ha-1∙yr-1 DM (2016). The total weighted average C yield ranged from 26.63±26.80 t∙ha-1∙yr-1 C (1984) to 77.45±40.19 t∙ha-1∙yr-1 C (2016). The average C yield related to the whole analyzed period (1984-2016) was 66.04 t∙ha-1 C. Of this, C yield in the aboveground wood biomass, belowground wood biomass and dead organic matter was equal to 72.0%, 15.8% and 12.2%, respectively. Validation of the results at the stand level was performed by comparing the value of the gross annual increment provided by the FMPs with the one predicted by WOCAS v2. The model caused, in some cases, an overestimation and, in other cases, an underestimation. For example, for Larix decidua Mill. and for Picea abies L., the Pearson coefficient of correlation (r2) between predicted and provided increments was r2 = 0.69 and r2 = 0.46, respectively. This was due to the fact that the methodology currently implemented into WOCAS v2 is based on average values of growth parameters valid for the whole Lombardy Region, and does not consider the productivity class of the stands since specific information was not always made available by the FMPs. WOCAS v2 also includes an innovative methodology (chapter 4 and chapter 5) to quantify – as an additional climate change mitigation strategy – the mass of potentially available residues (t·yr-1 DM) for energy generation, the potentially generated heat and electricity (GJ·yr-1) and the potentially avoided CO2 emissions into the atmosphere related to the final combustion process (t·yr-1 CO2), under the assumption that wood substituted non-renewable energy sources. In chapter 4, since not all the required data were initially made available for the Case Study Area, the mass of residues was computed by considering only the stand’s function and the stand’s management system, covering the period from 1994 (year in which the first wood cut was performed) to 2016. The calculation was then improved (chapter 5) by taking into account also the stand’s accessibility, the forest roads’ transitability and the energy market demand. Information on topographic features, landscape morphology and characteristics of the forest roads were collected by combining the FMPs data coming from WOCAS v2 and a Digital Elevation Model (DEM) in a Geographic Information System (GIS) software. The georeferenced stands were characterized by both single contiguous areas (single stands), as well as different non-contiguous areas (sub-stands). Overall, 2157 polygons – consisting of both single and sub-stands – were analyzed, covering the period from 2009 (most recent available data on forest roads’ transitability) and 2016. The mass of potentially available residues calculated for the analyzed period was used to estimate the current sustainable supply (i.e., 1.82∙103±6.61∙102 t·yr-1 DM). Under the hypothesis that these residues were prepared into woodchips to feed the Organic Rankine Cycle (ORC) unit of the local centralized heating plant of Ponte di Legno, the potentially generated heat and electricity (GJ·yr-1) and the potentially avoided CO2 emissions into the atmosphere (t∙yr-1 CO2) for the final combustion process were estimated by assuming that: (i) heat generated by the ORC unit replaced the one produced by natural gas-based heating plants; (ii) electricity generated by the ORC unit replaced the one generated by the Italian natural gas-based plants-mix for combined heat and electricity production and distributed through the National grid. Results showed that if only the current sustainable mass of residues was used to feed the ORC unit of the plant, the potentially generated heat and electricity would represent at most 28.7% of that generated by the unit in the year 2019. The thermal and electric power would be equal to 0.70 MW and 0.17 MW, with an average power load of the ORC unit of 23.6%. Experimental tests are needed to collect information on the harvesting method, used machines and technologies – which considerably affect the mass of available resides – as well as the currently harvested mass of residues for the validation of the results, that up to now is not possible since no measured data are available yet at the stand level. The second topic (forestry mechanization) is investigated in chapter 6. The aim is to develop an innovative approach in order to: (i) select the most suitable Forestry Machinery Chain (FMC) to adopt at the stand level for wood collection (harvesting and transport) and (ii) compute the economic costs (€·h-1; €·t-1 DM; €) of the selected FMC. To make the selection feasible, a user-friendly stand-level model called “FOREstry MAchinery chain selection” (FOREMA v1) was developed. FOREMA v1 supports the user in selecting the FMC according to seven technical parameters that characterize the stand. For each FMC, the model defines the sequence of the operations and the types of machines that can be used. The economic costs of the selected FMC are then quantified by taking into account the fixed and the variable costs. The approach was applied for a Case Study concerning the collection of woodchips from a coppice stand in the Italian Alps for energy generation. The analyzed FMC was made up of the following operations: (i) felling, (ii) bunching and extraction, (iii) chipping and (iv) loading and transport. For the whole FMC, the cost per unit of time was 669.3 €·h-1; the cost per unit of product was 113.0 €·t DM, whereas the cost of production amounted to 6893.2 €. Results provided by FOREMA v1 still need to be validated; experimental tests are required to collect information on the operating conditions in which the machines are actually used and, consequently, on the corresponding economic costs. Obtained results on the costs of the operations were compared with that reported in literature and related to studies performed under similar forestry and operating conditions.

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Li, Yaoxiang. « Modeling operational forestry problems in central Appalachian hardwood forests ». Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3814.

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Thesis (Ph. D.)--West Virginia University, 2005
Title from document title page. Document formatted into pages; contains ix, 144 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 107-114).

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Folegatti, Bruno da Silveira Smidt Mathew F. « The application of precision forestry technologies in logging operations ». Auburn, Ala., 2009. http://hdl.handle.net/10415/1975.

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Shrimpton, Nicole H. « An economic assessment of uneven-aged forestry based on the modelling of forestry operations ». Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/652.

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In recent years, interest in uneven-aged forestry has been increasing in Britain, particularly for sensitive areas such as recreation and amenity forests. Literature on the economics of uneven-aged forestry is scarce and few operational, uneven-aged forests are available for study. Therefore, in order to quantify the operating costs associated with uneven-aged forestry, a modelling approach was chosen. The resulting model is written in FORTRAN and uses a series of square two-dimensional arrays to represent a block of forest. The block may then be managed by clearfelling and replanting at a specified age, or by a system of group management with a choice of four group sizes. The resulting model was then used to investigate the effect of the following management strategies on operating times: 1. Varying the scale of working (i.e. the group size and forest size) in the uneven-aged forest. 2. Using shortwood or pole-length harvesting systems and a range of machine types within each harvesting system. 3. Varying the length of time taken to transform the structure of the forest from even-aged to uneven-aged. 4. Varying the age of the trees when the transformation from even-aged to uneven-aged structure begins. The results obtained from running the model show that the time taken to carry out an operation is influenced both by the absolute size of the group within the forest block and by the number of groups of that size within the forest block. This fragmentation effect explains why it is difficult to determine the absolute costs of working for a specific group size, because it is the combination of group size, number of groups and forest block size, which determines costs. Most of the results below are based on a range of group sizes from 1.000 ha. to 0.0625 ha., with a block size of 16 ha. Forwarders were penalized when the group size was decreased to 0.0625 ha. (-12% increase over clearfelling), because very small groups do not contain full forwarding loads and a large proportion of total forwarding time is spent manoeuvring into and out of groups. However, the operating times for the three group sizes 1.00 ha., 0.25 ha. and O. 1 1 ha. were very similar indicating that the group size can be quite small before any extra forwarding costs are incurred. On poor sites, the cost differential between the largest and smallest groups is greater. In contrast to forwarding, skidders are most penalized with the decision to adopt an uneven-aged system, and once that decision has been made, there is not a clear increase in costs with decreasing group size. During the transformation period, felling and thinning times in the uneven-aged system are significantly higher than those for the even-aged system, because trees are being harvested prematurely to create the early groups, but this difference is reduced once the forest is transformed. Felling and thinning times increase gradually as the group size decreases, because more care is needed for the felling operation and more time is needed for snedding coarse edge trees. Replanting times for the uneven-aged forest are approximately 8% - 14% higher than replanting times for clearfelling. The results from the model were then analysed using the EXCEL spreadsheet programme to examine, among other things, the cost implications of varying group size, and the relative profitability of uneven-aged and even-aged management. First,optimum ages to begin transformation were found, which varied with the Yield Class and discount rate chosen. Then, the effect of the length of the transformation period was examined and a long transformation period (80-years) was found to be preferable to a short transformation period (40-years). The analysis showed that at high discount rates even-aged and uneven-aged management had similar Net Present Values, but at lower discount rates the even-aged system was preferred. The greatest financial penalty was incurred with adoption of an uneven-aged system, and reducing the group size had relatively little impact on Net Present Values. Other costs and benefits, such as scenic beauty and recreation potential, could not be included in the model, because research relating these values to forest management variables has not been carried out. Therefore, these mostly non-financial factors were discussed for even-aged and uneven-aged forestry, based on a review of the literature.

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Coup, Charles E. « A Case Study Approach for Assessing Operational and Silvicultural Performance of Whole-Tree Biomass Harvesting in Maine ». Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/CoupCE2009.pdf.

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Hall, Edith Carol Sonne. « Greenhouse gas emissions from Pacific Northwest forestry operations : implications for forest management / ». Thesis, Connect to this title online ; UW restricted, 2005. http://hdl.handle.net/1773/5596.

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Barrett, Scott M. « Operational characteristics, erosion potential, and implementation of forestry best management practices on biomass harvesting operations ». Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23676.

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Utilization of woody biomass for energy is expected to increase rapidly and logging residues are a likely feedstock to meet increased demands. Potentials for increased biomass utilization have created concerns regarding possible impacts of using logging residues for energy. The overall goals of this project were to characterize biomass harvesting operations and to evaluate potential impacts on soil erosion and implementation of Best Management Practices (BMPs) for water quality on biomass harvesting sites. Results indicate that biomass harvesting was integrated into a wide range of logging businesses. Existing biomass harvesting businesses reported total production levels ranging from 6 to 250 loads per week. The majority (98%) of biomass harvesting operations utilized integrated harvesting techniques where roundwood and fuel chips were produced concurrently. Potential erosion rates and BMP implementation scores were evaluated on ten biomass and ten conventional harvest sites in the Piedmont of Virginia. This study of 20 sites found no significant differences in overall estimated erosion rates between biomass harvests (0.7 tons ac-1 yr-1) and conventional harvests (0.8 tons ac-1 yr-1) (p=0.8282). Additionally, there were no significant differences observed in overall BMP implementation scores for biomass (85.2%) and conventional (81.3%) harvests (p=0.5930). A separate, but related study evaluated BMP implementation over a three year period on 88 biomass and 284 conventional harvests in the Piedmont of Virginia. Within the seven logging related BMP categories, only the Streamside Management Zones (SMZs) category had significant differences between biomass (83.1%) and conventional harvests (91.4%) (p=0.0010). Implementation score differences were not caused by insufficient residues for stabilization of bare soil but were apparently the result of operational decisions which resulted in lower implementation of BMPs related to SMZs. Overall, these findings indicate that existing BMPs appear adequate to protect water quality on biomass harvesting operations in the Virginia Piedmont when appropriately implemented.
Ph. D.

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Flisberg, Patrik. « Application of operations research in operative planning in the forest industry / ». Linköping : Department of Mathematics, Linköpings universitet, 2007. http://www.bibl.liu.se/liupubl/disp/disp2007/tek1104s.pdf.

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Sianturi, Maikel. « Operations research applied to forestry management ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ53253.pdf.

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Wiebe, Jonathan Andrew. « Texture estimates of operational forestry parameters ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ35026.pdf.

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Johansson, Jerry. « Excavators and backhoe loaders as base machines in logging operations / ». Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5875-7.pdf.

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Ratnayake, Ranitha. « Remote sensing and GIS application for monitoring forest management operations ». Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/11309/.

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Satellite data potentially provide a useful tool for estimating forest cover and monitoring changes. Traditional forest surveying methods involve time consuming measurements of a large number of trees. Remotely sensed data may enable forest cover changes to be estimated very rapidly over large areas and with a minimum of ground data collection. At present the role of forest management in Britain is expanding, so that looking at forest cover changes is extremely useful for management purposes. The main task of this study was to detect plantation forest cover change information especially on thinned and clear cut areas. These changes were estimated using Normalised Difference Vegetation Index (NDVI) derived from SPOT HRV data, compared with Forestry Commission (FC) records and field investigations. To detect whether areas have been thinned and felled during the period of concern (1994-1997), three fundamental aspects were considered. First the pattern of forest cover was identified by using FC records and field investigations. This pattern was linked to SPOT data using NDVI. At this stage relationships between forest cover and structural variables (age, top tree height, mean diameter and basal area) were also examined. Second, changes over time were analysed by using NDVI measurements (1994-1997) and change detection methods, particularly to identify the pattern of felling. Third, pixel based forest cover changes in selected compartments were related and compared to FC thinning records and information collected by forest managers. A number of points about the ability of remote sensing techniques to provide an estimate of forest cover for management operations emerged from this study. First, it was found that NDVI changed spatially with different forest cover; spatial patterns were mainly identified in areas where major management operations (thinning and felling) were carried out. Second, temporal patterns of forest cover change, mainly due to felling operations were identified. Finally with a detailed analysis of thinned compartments, this study recognised changing patterns of forest cover, which were related to management operations. These findings should be very useful for operational planning in plantation forests. In particular, knowledge of spatial and temporal changes of forest cover may be useful in management operations where the availability of ancillary information is unreliable. These results appear to be sufficient for the initial stages of operational planning. However further investigations need to be undertaken to better understand a number of factors related to changes of forest cover.

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Arnold, Theresa Faye. « TESTING THE ACCURACY OF LIDAR FOREST MEASUREMENT REPLICATIONS IN OPERATIONAL SETTINGS ». MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-03232009-100909/.

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The repeatability of stand measurements derived from LiDAR data was tested in east-central Mississippi. Data collected from LiDAR missions and from ground plots were analyzed to estimate stand parameters. Two independent LiDAR missions were flown in approximate orthogonal directions. Field plots were generated where the missions overlapped, and tree data were taken in these plots. LiDAR data found 86-100% of mature pine trees, 64-81% of immature pine trees, and 63-72% of mature hardwood trees. Immature and mature pine tree heights measured from LiDAR were found to be significantly different (α= 0.05) than field measured heights. Individual tree volumes and plot volume for mature pines were precisely predicted in both flight directions. The results of this study showed that LiDAR repeatability in mature pines can be accurately achieved. But immature pine and hardwood plots were unable to match the repeatability of the mature pine plots.

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Lim, Lui Cheng. « Robust scheduling in forest operations planning ». Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45274.

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Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2008.
Includes bibliographical references (p. 67-68).
Forest operations planning is a complex decision process which considers multiple objectives on the strategic, tactical and operational horizons. Decisions such as where to harvest and in what order over different time periods are just some of the many diverse and complex decisions that are needed to be made. An important issue in real-world optimization of forest harvesting planning is how to treat uncertainty of a biological nature, namely the uncertainty due to different growth rates of trees which affects their respective yields. Another important issue is in the effective use of high capital intensive forest harvesting machinery by suitable routing and scheduling assignments. The focus of this thesis is to investigate the effects of incorporating the robust formulation and a machinery assignment problem collectively to a forest harvesting model. The amount of variability in the harvest yield can be measured by sampling from historical data and suitable protection against uncertainty can be set after incorporating the use of a suitable robust formulation. A trade off between robustness to uncertainty with the deterioration in the objective value ensues. Using models based on industrial and slightly modified data, both the robust and routing formulations have been shown to affect the solution and its underlying structure thus making them necessary considerations. A study of feasibility using Monte Carlo simulation is then undertaken to evaluate the difference in average performances of the formulations as well as to obtain a method of setting the required protections with an acceptable probability of infeasibility under a given set of scenarios.
by Lui Cheng, Lim.
S.M.

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Przybylko, Joshua. « The applications of autonomous systems to forestry management ». Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81014.

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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; in conjunction with the Leaders for Global Operations Program at MIT, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 132-137).
Public and private timberland owners continually search for new, cost effective methods to monitor and nurture their timber stand investments. Common management tasks include monitoring tree growth and tree health, estimating timber value and preventing wildfire. Many of these tasks are both manual and costly due to the vast areas and remote locations involved. Forestry experts predict that multi-vehicle autonomous systems may enable new, cost effective methods for performing various forest management tasks[1]. However, it remains unclear how these technologies may be applied, or where to focus development efforts. This research attempts to address this gap in literature, linking state-of-the-art research in forestry management science, robotics and autonomous systems, and product design and development. This thesis begins by reviewing existing forestry management practices and discussing a number of challenges identified through industry interviews and research. Modem product design methods are reviewed, and used to generate ideas for a number of new concept systems. Three design concepts are presented as detailed case studies. The data sets, methods and proposed systems discussed in this thesis may be used to guide future research in forestry management science, and drive further innovation in the emerging field of commercial and civilian autonomous systems. Key words: Forestry Management, Forestry Science, Robotics and Autonomous Systems, Unmanned Aerial Vehicles (UAV), Unmanned Aerial Systems (UAS), Product Design and Development, Light Detection and Ranging (LiDAR)
by Joshua Przybylko.
S.M.
M.B.A.

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Gunnarsson, Helene. « Supply chain optimization in the forest industry / ». Linköping : Department of Mathematics, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8856.

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Endahl, Jordan Brantley. « Urban Forest Waste Generation and Utilization by Municipal and Private Arboricultural Operations in Virginia ». Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/51567.

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Urban forest waste utilization has been identified as an essential component of the sustainable urban forest management system. To compile baseline data on generation and utilization of urban forest waste (UFW) in Virginia, 91 urbanized municipalities and 828 International Society of Arboriculture Certified Arborists operating privately in Virginia were invited to participate in a web-based survey. Results indicate that nearly three quarters (74%) of all respondents reported that their local operation generates UFW. For private arborists this included logs, brush, and chips generated by arboricultural practices, and for municipalities this included similar material generated by an in-house tree crew and similar material collected curbside from residents. Two-thirds (67%) of respondents could not estimate the amount of UFW generated by their local operations, but nearly half (47%) could report on its fate. The mean total amount generated was 315 tons/year/employee, or 945 tons/year for a typical tree crew. On average, both municipalities and private operations reported disposing less than 25% of their UFW at a solid waste facility. The majority of logs were utilized to produce firewood or lumber, while the majority of chips and brush were utilized to produce mulch or compost. Municipal operations utilized significantly more chips in-house compared to private arboricultural operations (p = 0.041). Regardless of operation type or UFW type, UFW is rarely left on-site, which indicates that UFW is being handled and transported in the majority of situations. If UFW is being mobilized, then perhaps there might be additional opportunities to divert materials into utilization streams rather than disposal streams. When characterizing the respondents' perceptions of urban forest waste utilization, two-thirds of respondents (65%) either agreed or strongly agreed that UFW utilization is a major issue for the urban forestry industry currently. An even higher percentage (76%) agreed or strongly agreed that UFW utilization will be a major issue for the urban forestry industry in the future. Results also indicate that the primary incentives to utilization were the avoidance of disposal fees and shipping costs. Municipal employees cited a lack of equipment as the primary barrier to greater waste utilization and frequently identified educational seminars or conferences as a technical assistance need. In contrast, private-sector arborists cited a lack of local processors as their primary barrier and frequently identified local facilities for receiving, sorting, and stockpiling UFW as a technical assistance need. These varying perceptions should be taken into account when developing future educational or technical programs aimed at increasing utilization in Virginia.
Master of Science

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Sørensen, Rasmus. « Influence of topography and forestry on catchments : soil properties, runoff regime, and mercury outputs / ». Uppsala : Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200985.pdf.

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Poff, Boris, et Daniel G. Neary. « International Co-Operative Program on Assessment and Monitoring of Air Pollution Effects on Forests : The Sierra Ancha Experimental Forest, Arizona ». Arizona-Nevada Academy of Science, 2008. http://hdl.handle.net/10150/296685.

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Mologni, Omar. « Cable tensile force monitoring in steep slope forest operations ». Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3426820.

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The interest in active sustainable management of mountain forests is increasing around the world. Great effort, in particular, is focusing on the identification of efficient, safe, and sustainable steep slope harvesting solutions adapted to different environmental conditions. The main attention is moving toward winch-assist harvesting systems on trafficable terrain and European designed standing skyline mobile tower yarders on non-trafficable terrain. These cable-supported harvesting solutions have similar safety issues related to the use of tensioned wire ropes and the use of natural anchors. This research focused on the analysis of cable tensile force while operating with these harvesting solutions in ordinary harvesting sites and operational conditions. First, a state-of-the-art about the steep slope cable-supported harvesting solutions and their main safety issues was completed. A particular focus was dedicated to the significant works on cable tensile force monitoring. Following, field studies were successfully carried out to monitor the cable tensile forces on ordinary logging operations. The survey interested eleven mobile tower yarders, observed on twelve different cable lines in the Italian Alps, and three large integrated-winch forwarders, observed on eight trails in the interior of British Columbia (Canada). A similar approach, based on the integration of tensile force monitoring, video recording of the operations, ground profile analysis, and load measurement/estimation, was applied to both the cable-supported systems. The case studies, the methodological approach used for the data collection and analysis, and the results of the monitoring are presented and reported in detail.

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Campos, Alexandre Arantes de. « Desempenho operacional e análise de custos da implantação florestal mecanizada de eucalipto ». Universidade Federal do Espírito Santo, 2013. http://repositorio.ufes.br/handle/10/5784.

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Made available in DSpace on 2016-12-23T13:51:47Z (GMT). No. of bitstreams: 1 Alexandre Arantes de Campos.pdf: 2259544 bytes, checksum: 5826ef0b242b57b0235485d774b6656e (MD5) Previous issue date: 2013-07-26
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This research aimed at analyzing the operational performance and machine cost of eucaliptus mechanized planting. The data were collected on Northern of Espírito Santo State and Southern of Bahía State. The operational analysis was based on time and motion studies, aiming to determine the distribution of operating time, machine availability, use rates, operating efficiency, machine productivity. The cost analysis was based on cost of planting tree operational activities. The following activities were evaluated: clearing of stand waste, subsoiling, marking the plating pit with fertilization, planting, chemical weeding, covering fertilization. According to the results, the highest productivity time (57,08%) was observed in São Mateus region where there was no difference among the activities. The highest mean accessory time (17,24%) was observed in Posto da Mata region, additionally, the lowest percentage values for subsoiling (11,56%) and marking the plating pit with fertilization (12,90%). Planting activity demanded highest auxiliary time for both regions, Posto da Mata (21,42%) and São Mateus (13,08%). São Mateus region showed the lowest mean unproductive time (10,59%), where the highest was found in subsoiling (23,93%) and lowest in planting (3,14%). Comparing the results among the different activities between the regions, subsoiling had the highest service time (15,65%) in Posto da Mata and clearing stand waste (18,19%) highest in São Mateus. The other activities did not differ from each other. Considering the mechanical availability, there was no difference among activities inside the regions, although subsoiling (96,17%) had the highest percent in São Mateus and clearing stand waste (95,87%) in Posto da Mata. The highest use rate (71,92%) and operational efficiency (64,17%) were found in São Mateus whereas, there was no difference among activities. The highest productivity was observed for fertilization in both regions, where 2,52ha.h-1 was found in Posto da Mata and 2,99ha.h-1 in São Mateus. The highest operating cost was due to subsoiling (R$112,80/ha) whereas, fertilization showed the lowest operating cost (R$12,22/ha). The best indicators were observed in São Mateus region (highest productive time, better machines and equipments efficient use and lowest cost)
Esta pesquisa teve como objetivo analisar o desempenho operacional e custo das máquinas nas operações mecanizadas de implantação florestal em plantios de eucalipto. Os dados foram coletados nas regiões norte do Espírito Santo e extremo sul da Bahia. A análise do desempenho operacional consistiu em estudo de tempos e movimentos, a fim de determinar a distribuição dos tempos operacionais, disponibilidade mecânica, grau de utilização, eficiência operacional e produtividade das máquinas. A análise de custos consistiu na estimativa dos custos operacionais nas atividades de implantação florestal. Foram avaliadas as operações de afastamento de resíduos, subsolagem, coveamento com adubação, plantio, capina química e adubação de cobertura. De acordo com os resultados, o maior percentual de tempo produtivo (57,08%) foi observado na região de São Mateus, sendo que não houve diferença entre as operações. A maior média de tempo acessório (17,24%) foi observada na região de Posto da Mata, e os menores percentuais nas operações de subsolagem (11,56%) e coveamento com adubação (12,90%). O plantio possui o maior tempo auxiliar em ambas as regiões, sendo 21,42% em Posto da Mata e 13,08% em São Mateus. A região de São Mateus possui menor média de tempo improdutivo (10,59%) sendo o maior valor na subsolagem (23,93%) e o menor no plantio (3,14%). Comparando os resultados das regiões dentro das operações, a subsolagem (15,65%) possui maior tempo de manutenção em Posto da Mata e o afastamento de resíduos (18,19%) maior em São Mateus. Nas demais operações não houve diferença. Com relação a disponibilidade mecânica, não houve diferença entre operações dentro das regiões, porém a subsolagem (96,17%) possui maior percentual em São Mateus e afastamento de resíduo (95,87%) em Posto da Mata. O maior grau de utilização (71,92%) e eficiência operacional (64,17%) foi em São Mateus, sendo que não houve diferença entre as operações. A maior produtividade foi observada na operação de adubação em ambas as regiões, sendo 2,52ha.h-1 em Posto da Mata e 2,99ha.h-1 em São Mateus. A operação com o maior custo foi a subsolagem (R$112,80/ha). A adubação possui o menor custo (R$12,22/ha). Os melhores indicadores foram observados na região de São Mateus (maior tempo produtivo, melhor eficiência na utilização das máquinas e equipamentos e menor custo)

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Lang, Albert Joseph. « Soil Erosion from Forest Haul Roads at Stream Crossings as Influenced by Road Attributes ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71707.

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Forest roads and stream crossings can be important sources of sediment in forested watersheds. The purpose of this research was to compare trapped sediment and forestry best management practice (BMP) effectiveness from haul road stream crossing approaches and ditches. The three studies in this dissertation provide a quantitative assessment of sediment production and potential sediment delivery from forest haul roads in the Virginia Piedmont and Ridge and Valley regions. Sediment production rates were measured and modeled to evaluate and compare road and ditch segments near stream crossings with various ranges of road attributes, BMPs, and management objectives. Sediment mass delivered to traps from 37 haul road stream crossing approaches ranged from <0.1 to 2.7 Mg for the one year collection. Collectively, five approaches accounted for 82% of the total sediment mass trapped. Approaches were categorized into Low, Standard, and High road quality rankings according to road attributes. Seventy-one percent (5 of 7) of Low ranked approaches delivered sediment to traps at rates greater than 11.2 Mg ha-1 yr-1. Nearly 90% of Standard or High road quality approaches generated less than 0.1 Mg of sediment over one year. Among approaches with less than 0.1 Mg of trapped sediment, road gradients ranged from 1% to 13%, bare soil ranged from 2% to 94%, and distances to nearest water control structures ranged from 8.2 to 427.0 m. Such a wide spectrum of road attributes with relatively low levels of trapped sediment indicate that contemporary BMPs can mitigate problematic road attributes and reduce erosion and sediment delivery. Three erosion models, USLE-forest, RUSLE2, and WEPP were compared to trapped sediment data from the 37 forest haul road stream crossing approaches in the first study. The second study assessed model performance from five variations of the three erosion models that have been used in previous forest operations research, USLE-roadway, USLE-soil survey, RUSLE2, WEPP-default, and WEPP-modified. The results suggest that these soil erosion models could estimate erosion and sediment delivery within 5 Mg ha-1 yr-1 for most approaches with erosion rates less than 11.2 Mg ha-1 yr-1, while model estimates varied widely for approaches that eroded above 11.2 Mg ha-1 yr-1. Based on the results from the 12 evaluations of model performance, the modified version of WEPP consistently performed better compared to all other model variations tested. However, results from the study suggest that additional field evaluations and improvement of soil erosion models are needed for stream crossings. The soil erosion models evaluated are not an adequate surrogate for informing policy decisions. The third study evaluated sediment control effectiveness of four commonly recommended ditch BMPs on forest haul road stream crossing approaches. Sixty ditch segments near stream crossings were reconstructed and four ditch BMP treatments were tested. Ditch treatments were bare (Bare), grass seed with lime fertilizer (Seed), grass seed with lime fertilizer and erosion control mat (Mat), rock check dams (Dam), and completely rocked (Rock). Mat treatments had significantly lower erosion rates than Bare and Dam, while Rock and Seed produced intermediate levels. Findings of this study suggest Mat, Seed, and Rock ditch BMPs were effective at reducing erosion, but Mat was most effective directly following construction because Mat provided immediate soil protection measures. Any BMPs that reduce bare soil can provide reduction in erosion and even natural site condition, including litterfall and invasive vegetation can provide erosion control. However, ditch BMPs cannot mitigate inadequate water control structures. Overall, forest roads and stream crossings have the potential to be major contributors of sediment in forested watersheds when roads are not designed well or when BMPs are not properly implemented. Forestry BMPs reduce stormwater runoff velocity and volume from forest roads, but can have varying levels of effectiveness due to site-specific conditions. Operational field studies provide valuable information regarding erosion and sediment delivery rates, which helps guide BMP recommendations and subsequently enhances water quality protection.
Ph. D.

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Hogg, Glynn A. « Multi-stem mechanised harvesting operation analysis : application of discrete-event simulation ». Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1973.

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Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009.
In this study, a multi-stem harvesting operation was observed and time studies carried out on its machines. A stump-to-mill simulation model (System 1) of this system was subsequently built using a commercial simulation software package (Arena 9) and data from the time studies were incorporated into the model. Following this, another two stump-to-mill multistem models (Systems 2 and 3) were built using the same simulation software package and parameterised input data. These two models represented hypothetical systems which were tested against System 1 and against one another in terms of machine balance within the system, production rate and cost. System 2 used identical equipment to System 1, but practised alternative operating methods. Some of System 3’s machines and operating methods differed from those in Systems 1 and 2. The objectives of the study were to: 1. Determine whether or not commercial simulation software can be used to adequately model forest harvesting operations. 2. Gauge potential system balance, production and/or cost improvement/s achievable through application of simulation-based operation adjustments. 3. Define beneficial equipment operation and application practises for multi-stem systems. 4. Through construction and use of the commercial software package in producing forest harvesting operation models, evaluate the software’s usability in terms of its applicability to and ease of use in such models, as well as its ability to meet forestrybased user requirements.

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Pledger, Sean. « Simulation modeling of forest biomass operations and harvest residue moisture content ». Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57858.

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In order to limit the effects of anthropogenic climate change the world is moving away from the use of fossil fuels as a primary energy source. Bioenergy is expected to form a substantial contribution to this transitional strategy. In order to increase bioenergy production, underutilized forest harvest residues are being targeted as a fuel source. Even with favorable policies in place to encourage their use, the processing and collection of these previously disregarded resources is often prohibitively expensive. Quality factors such as material moisture content also impact the viability of harvest residues for fuel purposes. As a result, careful operational planning is of great importance to sourcing high quality, economically feasible biomass. To gain a better understanding of the forest biomass supply chain, a simulation model was developed for a case study located in coastal British Columbia, Canada. A seasonal moisture content trend was identified and incorporated to help develop a strategy for sourcing high quality materials. It was found for BC’s coastal temperate rainforest environment that by delaying biomass collection until the second summer after timber harvest an average delivered moisture content of 28% can be achieved rather than 38% is operations proceed in the first summer. This reduction in delivered moisture content also led to a decrease in delivered cost from $72.08 to $67.95 per oven dried tonne. Trucking and equipment configurations were also examined to identify least cost approaches to biomass collection under varying conditions. Comparing high productivity and low productivity equipment configurations showed a $26.08/ODT cost increase when switching to less productive equipment. By employing an electric centralized grinder transporting unprocessed harvest residues, costs were shown to decrease for all cutblock groups with a cycle time of less than four and a half hours. Least cost fleet size was found to be largely dependent on the average cycle time to the biomass source. And the volume of available biomass at a given cutblock was found to have an impact on delivered costs with a 20% increase in biomass volume resulting in a cost decrease of greater than $2/ODT.
Forestry, Faculty of
Graduate

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Harrill, Hunter. « Improving Cable Logging Operations for New Zealand’s Steep Terrain Forest Plantations ». Thesis, University of Canterbury. Forestry, 2014. http://hdl.handle.net/10092/9923.

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Cable logging will become more important as harvesting shifts to greater annual proportions on steep terrain in New Zealand. The costs of cable logging are considerably higher than that of conventional ground-based methods. Improving cost-effectiveness has been identified as key to ensuring the forestry industry remains cost competitive in the international market. This thesis focuses on ways to better understand and improve cable logging methods by specifically focusing on rigging configurations. The investigation was conducted through a comprehensive literature review, an industry survey to establish current use and preferences, a Delphi survey with experts to establish actual advantages and disadvantages, scale model testing to establish some fundamental knowledge of tension to deflection relationship, and finally a series of targeted case studies to establish both productivity and skyline tension in actual operations. Each of these aspects of the research topic employed different methodology. The literature review highlighted the most relevant research relating to cable logging world-wide spanning nearly a century. Various research papers, manuals, books and computer software were summarized. While many aspects of cable yarding operations have been investigated, much of it focusing on various aspects of operational efficiency through case studies, there is very limited information with regard to rigging configurations. The survey of 50 cable logging practitioners determined what rigging configurations were commonly used in New Zealand. It includes their perceived advantages and disadvantages for varying levels of deflection, but also for specific scenarios such as pulling away from native forest boundaries and flying logs over a stream. Results showed that there were many conflicting perceptions about rigging configuration options. Using an expert panel, a Delphi process was used to derive consensus on what advantages were truly unique to each configuration. This allowed the longer lists of perceived advantages from the industry survey to be pared down to a concise list of ad/disadvantages that will be used in the updating of the Best Practice Guidelines for Cable Logging. To increase our fundamental understanding of tension / payload / deflection relationships, an experiment was conducted in a controlled environment. Using a model yarder in a lab and continuous tension and video recording devices, the dynamic skyline behavior of three similar configurations were tested: North Bend, South Bend and Block in the Bight. The tensions were compared by use of a two-way analysis of variance, which indicated configuration and choker length were significant variables in some but not all of the dynamic load tests. Results also showed that some configurations performed better than others in minimizing the shock loads due to dropping into full suspension, impact with ground objects, and breakout during bridling. Finally, a series of eight studies were conducted on targeted logging operations where relevant stand and terrain parameters were related to the continuous skyline tension monitoring, and recording of productivity through time study. The three targeted configurations included (1) North Bend, (2) Standing skyline using a motorized slack-pulling carriage and (3) a live skyline using a motorized grapple carriage. Results showed that peak and average tensions, as well as amplification factors and the payload to tension relationship, varied between configurations. The study also showed that tensions could be collected to compute measures of payload and tension efficiency, which provided insight into operational performance. The safe working load was exceeded in 53% of all cycles studied and across seven of eight study sites and 14 of 16 spans. Cycle times were significantly different between rigging configurations and that production information could be used to compute measures of labor and energy consumption as well as payload and tension efficiency; which also provide insight into operational performance. The industry should give serious consideration to the use of tension monitors. Tension monitors have many benefits and have the potential to improve cable logging operations in New Zealand. Monitoring tensions can help one learn new techniques or methods (i.e. rigging configurations), help improve payload analysis software for future planning and help evaluate new technology and machinery.

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Cristan, Richard. « Effectiveness of State Developed and Implemented Forestry Best Management Practices in the United States ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71657.

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The passage of the Federal Water Pollution Control Act of 1972 required states to develop forestry BMPs to help reduce potential nonpoint source pollution from forest operations. Properly applied forestry best management practices (BMPs) have since been proven to protect water quality from forest operations. This research project reviewed BMP effectiveness studies in the U.S., assessed current state developed and implemented of forestry BMPs, and developed a simple method to estimate potential erosion from forest operations for the Piedmont physiographic region based on previous studies. Eighty-one BMP effectiveness studies were reviewed. The review of past effectiveness studies indicates that water quality protection is increased when BMPs are implemented correctly. These effectiveness studies provide states with valuable information on how their BMP guidelines are achieving the goals defined by the Federal Water Pollution Control Act. Every U.S. state has forestry BMP guidelines. These guidelines may be non-regulatory, quasi-regulatory, or regulatory depending on the state. Twenty states reported implementing non-regulatory BMP guidelines, 19 quasi-regulatory BMP guidelines, and 11 regulatory BMP guidelines. State forestry agencies were reported as being the lead agency responsible for BMP monitoring in 35 states. The national forestry BMP implementation rate was 91% (32 states). However, states did report deficiencies for specific BMP guideline categories. Supplementary to the reviewed BMP effectiveness studies, forest erosion studies in the southeastern U.S. that quantified erosion rates from forest operations were also reviewed. Erosion rates obtained from the literature were reviewed by operation categories (timber harvesting, forest roads, skid trails, log landings, stream crossings, and streamside management zones) and physiographic region (Mountains, Piedmont, Gulf Coastal Plain, and Atlantic Coastal Plain). There were numerous research gaps regarding erosion rates from forest operations for all the regions except the Piedmont region. The Piedmont region was selected for developing a method to estimate potential erosion from forest operations. This erosion estimation method is a quick and potentially useful tool for estimating potential erosion; however, it is based on limited data from the Piedmont region only. The basic method approach might be considered for the other physiographic regions, but further research is needed to fill current knowledge gaps.
Ph. D.

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Muller, Richard B. « Operation and performance of a solar hardwood drying kiln utilizing natural dehumidification ». Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6483.

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Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The Saasveld solar kiln, valued at US$ 10,000 (R 70,000), is a greenhouse-type solar kiln requiring no additional heating. A unique auto-regulated process of natural dehumidification at night controls the humidity, and uses no venting system, nor any human/controller intervention. The natural dehumidification is achieved by circulating the humid kiln air through an air jacket on the periphery of the solar kiln. Diurnal temperature fluctuations allow condensation in the air jacket when air is cooled to below its dew-point temperature. The process is simple as colder night temperatures are a certainty. Almost no research has been done on similar kilns. The purpose of this thesis was to study the operation and performance of a solar drying kiln to dry high density hardwoods utilising natural dehumidification. The kiln load consisted of 20.1m 3 of a high density hardwood, Eucalyptus diversicolor, with air-dry density of 893kg/m 3 . The ZA Dry Q drying quality assessment indicated outstanding moisture distribution with little drying stress, a few surface checks and no internal checks, collapse, short bow or surface discolouration. The results conformed to the ZA Dry Q softwood appearance grade specification, except for end checks – remarkable for the drying of any hardwood. The final moisture content (MC) distribution was extremely tight with MC average of 11.5 per cent (%), standard deviation of 0.97% and the moisture gradient averaged 1.49%, standard deviation of 0.5%. The MC and MG were equally distributed in all three geometric directions throughout the load. The timber dried in 130 days. The kiln operation was analysed by temperature and humidity parameters at five positions inside and outside the kiln while monitoring the MC. The extent of moisture evaporation from the timber and the dehumidification of air were derived from this data. The results showed that the average of the daily kiln temperature, independent from the external temperature, increased from 18.0°C initially to 25.7°C. A maximum temperature of 38.1°C was recorded at the end of drying. Cell collapse did not occur under these low temperatures. Evaporation occurred generally from 07h30 to 16h45. The rate reduced at lower moisture contents. There was no effect of stack width. Natural dehumidification by condensation happened generally from 17h00 to 07h30. The equilibrium moisture content (EMC) decreased automatically from an initial daily average of 18.1% (variation 5%) to 8% (variation 2%) finally. It was similar to a smoothed T3C2–schedule. The mild drying conditions, with EMCs above 7.3%, ensured minimal moisture gradients and drying stresses. This reduced surface and internal checks. Nocturnal equalising and conditioning, comparable to intermittent schedules, resulted from: no evaporation, improved diffusion of heated timber and adsorption of moisture on the wood surface. The kiln protected the timber in extreme climatic conditions. It was found that the main circulating fan could be switched off from 17h00 to 07h30. A 30-minute manual venting at noon was permitted once fibre saturation point had been reached. Beneficiaries to this study can include hardwood processors who need to dry high density hardwoods within a reasonable time to an excellent drying quality. Processors in developing countries or who have little drying expertise could also benefit.
AFRIKAANSE OPSOMMING: Die Saasveld sondroër, met ‘n beraamde waarde van US$ 10,000 (R70,000), is ‘n groentetonneltipe sondroër met geen addisionele verhitting nie. ‘n Unieke auto-reguleerder beheer die humiditeit snags deur natuurlike dehumidifikasie. Dit gebruik geen ventileerder of enige menslike/kontroleerder inmenging nie. Die natuurlike dehumidifikasie word verkry deur die vogtige lug te sirkuleer deur ‘n lugkussing op die omtrek van die tonnel. Dag-en-nag temperatuur skommelings laat kondensasie toe binne-in die lugkussing sodra die lug benede die doupunttemperatuur afkoel. Dit is ‘n eenvoudige proses aangesien kouer nagte ‘n gegewe is. Byna geen navorsing is nog op soortgelyke sondroërs gedoen nie. Die doel van die tesis was om die werking en werkverrigting van ‘n sondroër wat hoë digtheid loofhout met behulp van natuurlike dehumidifikasie droog, te bestudeer. Die houtvrag het bestaan uit 20.1m 3 van hoë digtheid loofhout, Eucalyptus diversicolor, met ‘n gemiddelde lug-droë digtheid van 893 kg/m 3 . Die ZA Dry Q drogingskwaliteit toets het uitstaande resultate getoon. Daar was min drogingspannings, ‘n paar oppervlak krake en geen interne krake, sel-ineenstorting, kort-boog of oppervlak-verkleuring nie. Die resultate bevredig die ZA Dry Q naaldhout voorkomsgraad spesifikasie, behalwe vir end-krake – merkwaardig vir die droging van enige hoë digtheid loofhout. Die finale vogverspreiding was nou-verspreid met ‘n gemiddelde voggehalte van 11.5%, standaard afwyking van 0.97% en ‘n gemiddelde vog-gradiënt van ‘n 1.49%, standaard afwyking van 0.5%. Die voggehalte en vog-gradiënt was eweredig verspreid in al drie geometriese rigtings van die houtvrag. Die hout het in 130 dae gedroog. Die werking van die sondroër is geanaliseer deur temperatuur- en humiditeits-parameters by vyf posisies binne- en buite die droogkamer tegelykertyd met die voggehalte te monitor. Die omvang van vogverdamping uit die hout en dehumidifikasie van die lug is afgelei van hierdie data. Die gemiddelde daaglikse sondroër-temperatuur, wat onafhanklik van die buite temperatuur was, het verhoog van 18.0°C aanvanklik tot 25.7°C. Die maksimum temperatuur van 38.1°C is gemeet aan die end van droging. Sel-ineenstorting het nie voorgekom by hierdie lae temperature nie. Verdamping het algemeen voorgekom vanaf 07h30 tot 16h45, teen ‘n vertragende verdampingstempo by laer voggehaltes. Die stapelwydte-effek was van geen belang nie. Natuurlike dehumidifikasie deur kondensasie het gereeld voorgekom vanaf 17h00 tot 07h30. Die ewewigsvoggehalte (EVG) het outomaties verminder vanaf ‘n aanvanklike daaglikse gemiddelde van 18.1% (variasie van 5%) na 8% (variasie van 2%). Dit was soortgelyk aan ‘n gelykmatige T3C2 –drogingskedule. Die matige drogingskondisies, met EVG bokant 7.3%, het minimale vog-gradiënte en drogingspannings verseker wat oppervlak-krake en interne-krake verhoed het. Nagtelike houtvog egalisasie en kondisionering, vergelykbaar met puls-humiditeit skedules, was die gevolg van: geen verdamping, verbeterde diffusie in verhitte hout en adsorpsie van vog op die hout oppervlak. Die droogkamer het die hout beskerm teen buitengewone klimaatstoestande. Daar is gevind dat die hoof-waaier afgeskakel kan word vanaf 17h00 tot 07h30 en dat ‘n 30-minute nie-outomatiese ventilering smiddae kan plaasvind sodra veselversadigingspunt bereik is. Hierdie studie sal van nut wees vir die loofhout verwerkers wat hoë-digtheid loofhout moet droog binne ‘n redelike tydperk met ‘n uitstekende drogings-kwaliteit, asook houtverwerkers in opkomende lande of met gebrekkige drogingsvaardighede.

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Dong, Xiaowei. « Initial concepts to develop a semi-autonomous operator support technology for operating a novel forestry machine ». Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-154748.

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Forestry machines have the power to lift heavy logs, but they are not so smart at providing information, or help operators perform better work. The main reason to this problem is the low level of technology applied to forestry machines, which has not changed so much since the forestry machines were first introduced in the 1960’s. But starting 2013, machines manufacturers got inspired by developments in the automation and robotics industry, several of new technologies have been developed in the market - computerized hydraulics, feedback controllers for vibration damping, sensor-based motion control systems, improvements in mechanical design, smart suspension controller, etc. Largely, this development is attributed to better hardware and software developed during the last decade by researchers of Scandinavian institutes. In this thesis, we introduce a new type of forestry machine, the harwarder, which can perform the work of two machines (harvester and forwarder) by a single one. The forwarder is a forestry vehicle that carries big felled logs. The harvester is a type of heavy forestry manipulator employed in cut-to-length logging operations for felling, and bucking trees. Both the manipulator and vehicle should work synchronized to get the best out of this design. To benefit out of its design, in the first part of thesis we will analyze the kinematics and dynamics of machine, and design a time optimal coordinated motion via virtual holonomic constraints, to solve a particular task of forestry crane. The second part consists on applying optimization to reduce energy consumption during the motion. Result of thesis work: 1) By using coordinated motion, consequently the energy consumptions are drastically reduced comparing to traditional motion of the crane. 2) By applying optimization, the energy efficiency is improved.

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Ndoumbe, Berock Isaac Bernard. « Construction de la responsabilité sociétale des entreprises (RSE) dans les pays en développement : une application dans les entreprises d'exploitations forestières au Cameroun ». Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAB004.

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Face à un environnement incertain marqué par une instabilité sans cesse croissante, les entreprises s’efforcent de rechercher la performance à la fois globale et durable considérée désormais comme un levier non seulement de pérennité, mais aussi d’avantage concurrentiel primordial (Porter et Kramer, 2006; Crane et Matten, 2004). Ainsi, la responsabilité sociétale de l’entreprise (RSE) est perçue comme un thème fédérateur en sciences de gestion et de par sa dimension sociétale dans les sciences économiques et sociales prenant tout son sens dans le management opérationnel des entreprises. Considérée comme le prolongement de la prise en compte du développement durable (rapport Brundtland 1987) dans ses implications managériales, la RSE cristallise l’attention de nombreux chercheurs depuis plusieurs décennies, notamment dans sa dimension sociale, environnementale et normative (ISO 14000) depuis une vingtaine d’année et sociétale (ISO 26000) depuis les années 2000. Si la littérature foisonnante sur le concept de RSE reste en débat, force est de constater qu’elle traite très peu des mécanismes de construction des pratiques RSE et moins encore du rôle que les stakeholders jouent dans cette construction. Dans un tel contexte, prenant appui sur la stakeholder theory (Freeman, 1984; Oliver, 1991; Clarkson, 1995; Mitchell et al., 1997; Sethi, 1995; Rowley, 1997), l’analyse des données collectées suite à une investigation de huit mois auprès de six entreprises forestières au Cameroun, révèle d’une part que le modèle de Carroll (1979, 1991) de la RSE est contingent au contexte et que le comportement stratégique orienté RSE des entreprises du secteur de l’industrie forestière au Cameroun est fortement corrélé à la nationalité de l’entreprise. D’autre part, cette étude fait état de ce que la variable « champ d’activité » a un effet non déterminé sur le comportement stratégique adopté par les entreprises de ce secteur forestier. Enfin, cette recherche révèle également que la certification forestière FSC représente le gage d’un engagement volontaire en matière de RSE des entreprises d’exploitations forestières au Cameroun. La présente recherche ouvre la voie aux travaux futurs pour internaliser les pratiques de la RSE par les parties prenantes dans le management stratégique des entreprises les plus confrontées aux défis environnementaux
In an uncertain environment that is also marked by a growing instability, firms try to seek a global and sustainable performance which is considered as a lever not only for longevity but also for competitive advantage (Porter and Kramer, 2006; Crane and Matten, 2004). Thus, corporate social responsibility (CSR) is perceived as a unifying topic in management science and, by its societal dimension, in the economic and social sciences. Considered as an extension to the consideration of sustainable development in its managerial implications (Brundtland report, 1987), CSR has been at the attention of a large number of researchers for several decades now, in particular for twenty years in its social, environmental and normative dimension (ISO 14000) and since the 2000’s in its societal nature.While the concept of CSR is still under debate in its rather large literature, it should also be noted that this literature is usually silent on the construction mechanisms of CSR practices and even more on the role that stakeholders play in this construction.In this context, and relying on stakeholder theory (Freeman, 1984; Oliver, 1991; Clarkson, 1995; Mitchell et al., 1997; Sethi, 1995; Rowley, 1997), the present analysis of the collected data from an eight-month-long in-depth investigation of six forestry firms in Cameroun yields several findings: First, the CSR model in Carroll (1979, 1991) is contingent to the context and the strategic CSR behaviour of the different firms in the forestry industry in Cameroun is strictly correlated to the nationality of these firms. Second, this study shows that the “field of action” variable has a non-significant effect on the strategic behaviour adopted by the firms in this forestry industry. Finally, this research also reveals that the Forest Stewardship Council (FSC) certification represents the deposit of a voluntary commitment in terms of CSR of the forestry exploitation firms in Cameroun. The present work also opens new lines for future research focussing on the internalisation of the CSR practices by the contracting parties in strategic management of the firms that are in direct confrontation to the environmental challenges

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Sajdak, Magdalena. « INDIRECT METHODS FOR RESIDUAL BIOMASS MEASUREMENT COMING FROM PRUNING OPERATIONS OF URBAN FORESTS ». Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/17940.

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Una gran cantidad de biomasa residual con posible uso energético e industrial puede ser extraida de las operaciones de gestión de los árboles ornamentales de las ciudades. La rentabilidad del aprovechamiento de estos recursos está condicionada por la cantidad de biomasa existente en los ecosistemas urbanos. Esta investigación se ha centrado en la cuantificac ión directa e indirecta de los residuos biomásicos de la poda de árboles urbanos ornamentales. Las especies estudiadas fueron Morus alga, Platanus hispanica, Sophora japonica, Phoenix camariensis dactilifera las cuales son ampliamente utilizadas como vegetación ornamental en los países mediterráneos. Modelos matemáticos para la predicción de la cantidad residual de poda disponible han sido desarrollados para cada especie a partir de parámetros dendrométricos de fácil medición, tales como diámetro del tallo a altura del pecho, diámetro de copa o altura total, resultando coeficientes de determinación entre 0.67 y 0.96. Estas ecuaciones pueden ser utilizadas para los inventarios urbanos y la aplicación de los modelos logísticos. Por otra parte, se han analizado técnicas de escaneado con láser terrestre (TLS) para mejorar las estimaciones de los parámetros dedrométicos de árboles existentes, y relacionarlos también con esta bi0omasa residual obtenida. Para ello se han calculado los volúmenes aparentes de la copa con 4 métodos diferentes: global convex hull para la nube de puntos que forma toda la copa, convex hull por capas de 5 cm de altura en el plano XY, triangulación por secciones planas XY y discretización de la nube de puntos en los pequeños elementos de volumen (voxel). Finalmente, la biomasa residual de cada especie fue clasificada y caracterizada de acuerdo con las normas UNE incluyendo análisis de las dimensiones de los materiales obtenidos, densidad, humedad, poder calorífico, contenido de carbono, nitrógen o y azufre. Modelos para la predicción del poder calorífico superior a partir de la composición el
Sajdak, M. (2012). INDIRECT METHODS FOR RESIDUAL BIOMASS MEASUREMENT COMING FROM PRUNING OPERATIONS OF URBAN FORESTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17940
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Marques, Alexandra Sofia da Fonseca. « New decision support tools for forest tactical and operational planning ». Doctoral thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5205.

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Doutoramento em Engenharia Florestal e dos Recursos Florestais - Instituto Superior de Agronomia
The economic importance of the forest resources and the Portuguese forest-based industries motivated several studies over the last 15 years, particularly on strategic forest planning. This thesis focuses on the forest planning processes at tactical and operational level (FTOP). These problems relate to harvesting, transportation, storing, and delivering the forest products to the mills. Innovative Operation Research methods and Decision Support Systems (DSS) were developed to address some of these problems that are prevalent in Portugal. Specifically, Study I integrates harvest scheduling, pulpwood assortment, and assignment decisions at tactical level. The solution method was based in problem decomposition, combining heuristics and mathematical programming algorithms. Study II presents a solution approach based on Revenue Management principles for the reception of Raw Materials. This operational problem avoids truck congestion during the operation of pulpwood delivery. Study III uses Enterprise Architecture to design a DSS for integrating the operations performed over the pulpwood supply chain. Study IV tests this approach on a toolbox that handled the complexity of the interactions among the agents engaged on forest planning at regional level. Study V proposes an innovative technological framework that combines forest planning with forest operations' control.

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Kuruvilla, Annie S. « Operational Evaluation of Volume Sources Using Duke forest Field Study ». University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1124802092.

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Tinambunan, Djaban. « Strategic planning models for timber harvesting operations in the tropical rain forests of Indonesia / ». Thesis, Connect to this title online ; UW restricted, 1986. http://hdl.handle.net/1773/5525.

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Simpson, Brian N. « Water quality effects of forest operations on fourth, fifth, and sixth order streams ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0027/MQ62154.pdf.

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中澤, 昌彦, et Masahiko NAKAZAWA. « 森林施業の実態に基づいた森林基盤設備に関する研究 ». 名古屋大学農学部付属演習林, 2005. http://hdl.handle.net/2237/8634.

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Rodrigues, Carolina Bozetti. « Efeitos do manejo de florestas plantadas de Eucalyptus sobre os recursos hídricos superficiais na escala de microbacias hidrográficas ». Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-25072017-163038/.

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O Eucalyptus é o gênero florestal mais plantado no Brasil (5,6 milhões de hectares) e o Estado de São Paulo apresenta a segunda maior área plantada do país, com pouco mais de 970 mil hectares. O manejo intensivo das florestas plantadas de Eucalyptus, caracterizado pela alta produtividade, rápido crescimento e ciclos curtos de rotação, bem como a expansão do setor florestal, têm causado preocupações em relação aos efeitos desses plantios sobre a quantidade e a qualidade dos recursos hídricos. Diante desse contexto, esta tese foi desenvolvida com o objetivo de contribuir com o aprofundamento do conhecimento sobre os efeitos do manejo de florestas plantadas de Eucalyptus sobre os recursos hídricos. Para tanto, o segundo capítulo sintetiza os resultados de estudos já desenvolvidos no Brasil e que envolveram a mensuração de componentes do balanço hídrico em florestas plantadas de Eucalyptus e em diferentes biomas brasileiros, destacando os resultados dos estudos realizados em microbacias hidrográficas cobertas por florestas plantadas de Eucalyptus. No terceiro capítulo foram avaliados os efeitos da colheita florestal e do crescimento de florestas plantadas de Eucalyptus sobre o regime hidrológico de quatro microbacias hidrográficas e, no quarto capítulo, os efeitos sobre a qualidade da água e a exportação de nutrientes e sólidos suspensos. A revisão demonstrou que existem diferenças entre florestas plantadas de Eucalyptus e vegetação nativa, principalmente em relação aos valores anuais de rendimento hídrico (razão entre deflúvio e precipitação - Q:P), os quais tendem a diminuir, em microbacias hidrográficas, entre o primeiro e sétimo ano de idade das florestas plantadas. Os resultados demonstraram a existência de efeitos do manejo florestal como o aumento do rendimento hídrico (34%), do índice de escoamento base (4%) e do coeficiente de escoamento (21%) no primeiro ano depois da colheita (DC1) em relação ao ano anterior à colheita (AC), e a diminuição em 10%, 7% e 2%, respectivamente, no quarto ano depois da colheita (DC4) em relação ao ano DC1; o aumento da concentração de sólidos suspensos no ano DC1 em relação ao ano AC e a diminuição significativa dessas concentrações no ano DC4 em todas as microbacias estudadas; e o aumento das exportações de nutrientes e sólidos suspensos no ano DC1 acompanhando o aumento do rendimento hídrico e a diminuição das exportações no ano DC4 acompanhando a diminuição do rendimento hídrico. Em todas as escalas de análise do regime hidrológico (anual, sazonal e diária) foram observadas dinâmicas individuais nas microbacias hidrográficas diferentes daquelas observadas nos valores médios, demonstrando que outros fatores como, por exemplo, a precipitação, o tipo de solos e a declividade média, também podem influenciar o regime hidrológico além do manejo florestal. Esses efeitos demonstram que existe relação entre o manejo florestal e os recursos hídricos, mas não é possível afirmar que eles comprometem a quantidade e a qualidade da água. No entanto a conjunção entre fatores climáticos, características locais e as fases do manejo florestal pode agravar ou atenuar os efeitos sobre a quantidade e a qualidade da água, devendo esses aspectos serem observados nos planos de manejo florestal.
Eucalyptus is the most planted forest genus in Brazil (5.6 million hectares) and the State of São Paulo has the second largest planted area in the country, with over 970,000 hectares. The intensive management of forest plantations of Eucalyptus, characterized by high productivity, rapid growth and short rotation cycles, as well as the expansion of the forest sector, have caused concerns about the effects of these plantations on the quantity and quality of water resources. In this context, this thesis has been developed in order to contribute to the deepening of knowledge about the effects of Eucalyptus forest plantations management on water resources. Therefore, the second chapter summarizes the results of studies already developed in Brazil involving the measurement of water balance components in Eucalyptus plantations in different biomes, highlighting the results of studies in catchments covered by Eucalyptus forest plantations. In the third chapter, we evaluated the effects of Eucalyptus plantations harvesting and growth on hydrological regime of four catchments. In the fourth chapter, we evaluate effects on water quality and nutrient and suspended solids exports. The review has shown that there are differences between Eucalyptus forest plantations and native vegetation, especially in relation to annual values of discharge/precipitation ratio, which tend to decrease in catchments, between the first and seventh year on planted forests. The results demonstrated the existence of effects due to forest management such as increase in discharge/precipitation ratio (34%), base flow index (4%) and quick flow/precipitation ratio (21%), in the first year after harvest (DC1) in relation to the previous year before harvest (AC), and decreased by 10%, 7% and 2%, respectively, in the fourth year after harvest (DC4) compared to the DC1 year; concentration of suspended solids in DC1 year in relation to AC year and a significant decrease in these concentrations in DC4 year in all studied catchments; and the increase in nutrient exportation and suspended solids in DC1 year with increase in discharge/precipitation ratio and decrease in exports in the year DC4, accompanied by the decrease in discharge/precipitation ratio. In all scales of hydrological regimes (annual, seasonal and daily), individual dynamics were observed in different catchments from those observed in the mean values, demonstrating thus that other factors such as, for example, precipitation, soil type and the average slope, can also influence hydrological regime beyond forest management. These effects show that there is a relationship between forest management and water resources, but it is not possible to say that they compromise water quantity and quality. However, the conjunction of climatic factors, local conditions and stages of forest management can aggravate or mitigate the effects on water quantity and quality, and thus, such aspects should be observed in forest management plans.

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Rousseau, Mélanie. « Multi-scale analysis of the effects of forestry operations on the stream morphology and sedimentology of the Cascapédia River, eastern Québec ». Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81429.

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Forest harvesting is blamed for a perceived increase in the flashiness and turbidity of the Cascapedia River's water. This has raised questions over the source of the sediment (harvest parcels, roads, or stream banks) and its potential impact on the sedimentology of the river. The objectives of this research are twofold. The first is to ascertain if harvesting operations are associated to a widening of low-order tributaries, creating a source of sediment. The second is to determine if variations in the sedimentology along four segments of the Cascapedia can be associated to harvesting operation intensity. Firstly, analysis of stream width in low-order tributaries shows that, once the variations associated with basin area and D50 are removed and within the range of harvesting in our dataset, there appears to be a 25% increase in width associated with the harvesting activities of the last five years, as well as with road density, both in a 60 m stream buffer for a number of the sampled streams. Secondly, the models relating harvesting intensity and changes in sedimentology are sensitive to a few sites or contrary to theory. Future studies should determine the underlying hydrological processes responsible for stream enlargement and the process of sediment deposition.

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Oborn, Ragnar M. R. « A mathematical programming application with semi-continuous variables for multi-faceted forest operations planning ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23829.pdf.

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Green, Patrick Corey. « Decision Support for Operational Plantation Forest Inventories through Auxiliary Information and Simulation ». Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/103054.

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Informed forest management requires accurate, up-to-date information. Ground-based forest inventory is commonly conducted to generate estimates of forest characteristics with a predetermined level of statistical confidence. As the importance of monitoring forest resources has increased, budgetary and logistical constraints often limit the resources needed for precise estimates. In this research, the incorporation of ancillary information in planted loblolly pine (Pinus taeda L.) forest inventory was investigated. Additionally, a simulation study using synthetic populations provided the basis for investigating the effects of plot and stand-level inventory aggregations on predictions and projections of future forest conditions. Forest regeneration surveys are important for assessing conditions immediately after plantation establishment. An unmanned aircraft system was evaluated for its ability to capture imagery that could be used to automate seedling counting using two computer vision approaches. The imagery was found to be unreliable for consistent detection in the conditions evaluated. Following establishment, conditions are assessed throughout the lifespan of forest plantations. Using small area estimation (SAE) methods, the incorporation of light detection and ranging (lidar) and thinning status improved the precision of inventory estimates compared with ground data alone. Further investigation found that reduced density lidar point clouds and lower resolution elevation models could be used to generate estimates with similar increases in precision. Individual tree detection estimates of stand density were found to provide minimal improvements in estimation precision when incorporated into the SAE models. Plot and stand level inventory aggregations were found to provide similar estimates of future conditions in simulated stands without high levels of spatial heterogeneity. Significant differences were noted when spatial heterogeneity was high. Model form was found to have a more significant effect on the observed differences than plot size or thinning status. The results of this research are of interest to forest managers who regularly conduct forest inventories and generate estimates of future stand conditions. The incorporation of auxiliary data in mid-rotation stands using SAE techniques improved estimate precision in most cases. Further, guidance on strategies for using this information for predicting future conditions is provided.
Doctor of Philosophy
Informed forest management requires accurate, up-to-date information. Groundbased sampling (inventory) is commonly used to generate estimates of forest characteristics such as total wood volume, stem density per unit area, heights, and regeneration survival. As the importance of assessing forest resources has increased, resources are often not available to conduct proper assessments. In this research, the incorporation of ancillary information in planted loblolly pine (Pinus taeda L.) forest inventory was investigated. Additionally, a simulation study investigated the effects of two forest inventory data aggregation methods on predictions and projections of future forest conditions. Forest regeneration surveys are important for assessing conditions immediately after tree planting. An unmanned aircraft system was evaluated for its ability to capture imagery that could be used to automate seedling counting. The imagery was found to be unreliable for use in accurately detecting seedlings in the conditions evaluated. Following establishment, forest conditions are assessed at additional points in forest development. Using a class of statistical estimators known as small-area estimation, a combination of ground and light detection and ranging data generated more confident estimates of forest conditions. Further investigation found that more coarse ancillary information can be used with similar confidence in the conditions evaluated. Forest inventory data are used to generate estimates of future conditions needed for management decisions. The final component of this research found that there are significant differences between two inventory data aggregation strategies when forest conditions are highly spatially variable. The results of this research are of interest to forest managers who regularly assess forest resources with inventories and models. The incorporation of ancillary information has potential to enhance forest resource assessments. Further, managers have guidance on strategies for using this information for estimating future conditions.

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Villa, Murillo Adriana. « Optimización del diseño de parámetros : Métodos Forest-Genetic ». Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/17531.

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En el entorno altamente competitivo en que hoy se mueven las empresas, la calidad se ha convertido en la herramienta clave de supervivencia de las mismas. Hoy en día es generalmente aceptado que esa calidad debe ser conseguida desde el diseño, tanto de los productos como de los procesos. Taguchi propone la metodología del diseño robusto de parámetros con el fin de diseñar productos menos sensibles a los factores aleatorios o de ruido que hacen que varía los parámetros que definen su calidad. Tal metodología ha sido comunmente empleada en la industria a pesar de las grandes controversias que despertó desde sus inicios. El presente trabajo aporta una alternativa completa y estadísticamente robusta para la mejora del diseño de parámetros considerando en primer lugar experimentos con una sola característica de calidad como respuesta y posteriormente generalizado a casos con multiples características de calidad. Tal propuesta, definida como Métodos Forest-Genetic, combina herramientas de minería de datos y metaheurísticas en 3 fases: nomalización, modelización y optimización Tanto para el caso univariante como para el caso multivariante se comparan los resultados de forma numérica con los aportes más recientemente encontrados en la literatura mediante 4 casos de estudio diferentes. Pudimos verificar que nuestra propuesta metodológica se concentra en las variables de mayor importancia producto del proceso de modelización, lo que nos permite alcanzar importantes mejoras en cuanto al objetivo de calidad considerado en cada caso.
Villa Murillo, A. (2012). Optimización del diseño de parámetros: Métodos Forest-Genetic [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17531
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Truong, Gold. « Forecasting linehaul transit times & ; on time delivery probability using quantile regression forests ». Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90751.

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Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2014. In conjunction with the Leaders for Global Operations Program at MIT.
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 85).
with delays on the road and variabilities introduced by the major participants in the process, ie: distribution centers, drivers, etc. These sources of variability also make it difficult to measure the impact changes in transit time have on on-time performance. This paper focuses on trying to identify indicators of variability and incorporates them into quantile regression forest, a black box forecasting model, that will provide estimated scheduled transit times for a given probability of on-time arrival at the destination. With the use of Amazon's Q1 & Q2 2013 linehaul data, an analysis on performance trends based on length of haul were categorized to develop an understanding linehauls in North America. The outbound transportation team at Amazon faces the complex trade off between providing a sufficient amount of scheduled transit time to ensure ontime delivery to destination and the utilization rate of a truck. The ability to quantify how changes in scheduled transit time impact the performance of a particular linehaul allows transportation managers to assess this trade off. The paper explores a machine learning regression technique called quantile regression forests. The model was developed in R using the quantregforest package. It incorporates numerous factors about linehaul including: origin, destination, historical reporting on sources of late to arrivals, time to depart from origin and time of departure. The strengths of this black box model are in its ability to handle a large amount of data and continuously update its predicting structure to provide more accurate recommendations. Quantile regression forests also enable the user to specify the ontime performance percentage, p, that he/she wants the model to predict based on historical data. The final model at p = 95% provided a weight mean absolute percent error of 4.57% and a root mean square error of 2.22%. A four-week pilot was conducted to validate these predictions and the results are discussed.
by Gold Truong.
M.B.A.
S.M.

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Souza, Franciny Lieny. « Densidade de estradas em povoamentos de Pinus taeda l. em regime de desbastes e corte raso ». Universidade do Estado de Santa Catarina, 2016. http://tede.udesc.br/handle/handle/2337.

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The objective of the present research was to analyze timber extraction operations and determining economically optimal density of forest roads in thinnings and clear cut for Pinus stands managed for multiple use, subsidizing the operations planning for forest sustainability. The survey was conducted in areas of harvest of Pinus taeda L., belonging to Florestal Gateados Ltda, in Campo Belo do Sul, SC. The study was divided into two stages. In the first, a technical analysis, modeling and cost productivity of logging activities in different situations and machines: (a) first thinning in cut to lenght system (CTL) with forwarder; (b) third roughing in CTL system with forwarder; (c) clear cut in with forwarder CTL system; and (d) clear cut in full tree system (FT) with skidder. Technical analysis was performed by means of a time and motion study, with a sampling error of less than 10%, being evaluated the elements of the operating cycle and given nominal productivity (Pn) and effective (Pe). The cost analysis was accomplished through the determination of production and operational costs for the accounting method. The operations were evaluated in different conditions of slope, direction of operation, distance of extraction, presence of rocky outcrop and volume by class tora, which were also regarded as independes variables to fit mathematical models for multiple regression for estimation of productivity, using the Stepwise Procedure. The main results were: for the first trim the Pn was 10,90 m3/h and total operating cost (COT) of R$/he. 181,12 For the third roughing the NP was 16,45 m3/h and COT of 185,58 R$/he. In clear cut, for forwarder if a Pn of 29,05 m3/h and COT of 244,58/he R$, while for the skidder obtained a Pn of 128,60 m3/h and COT of 218,31 R$/he. For the modeling of productivity of machines, the distance and the volume by tora were used as explanatory variables, being present in the estimates for the forwarder, in addition to the volume per cycle, in third, and slope in the first thinning and clear-cutting. For the skidder, the variables used were the distance and volume per cycle. In step two was given the economically optimum density (DOE) and acceptable (DAE) for different situations. The DOE was calculated by the indirect method, which is the product of the sum of the costs of reconstruction, maintenance, extraction and waste of productive area. First trim the current road density (of) was 45,28 m/ha, the DOE of 20,18 m/ha and the DAE of 28,26 m/ha. Third roughing the of was 95,08 m/ha, the DOE of 16,60 m/ha and the DAE of 21,68. In clear-cutting the of was 92,02 w/ha, being the DOE for the CTL system of 15,63 m/ha and DAE of 24,75 m/ha, while in the FT system DOE was 22,85 m/ha and 27,00 m DAE/ha. In General, the density of current roads was above the good and acceptable and should be carried out a redesign of operations targeting a road network within the acceptable density, resulting in lower costs and increased revenue to the company
O objetivo da presente pesquisa foi analisar operações de extração de madeira e determinar economicamente a densidade ótima de estradas florestais em desbastes e corte raso para povoamentos de Pinus manejados para uso múltiplo, subsidiando o planejamento das operações com vistas à sustentabilidade florestal. A pesquisa foi realizada em áreas de colheita de Pinus taeda L., pertencentes à empresa Florestal Gateados Ltda, em Campo Belo do Sul, SC. O estudo foi dividido em duas etapas. Na primeira, foi realizada uma análise técnica, de custos e modelagem da produtividade das atividades de extração de madeira em diferentes situações e máquinas: (a) primeiro desbaste em sistema de toras curtas (CTL) com forwarder; (b) terceiro desbaste em sistema CTL com forwarder; (c) corte raso em sistema CTL com forwarder; e (d) corte raso em sistema de árvores inteiras (FT) com skidder. A análise técnica foi realizada por meio de um estudo de tempos e movimentos, com um erro amostral menor que 10%, sendo avaliados os elementos do ciclo operacional e determinada a produtividade nominal (Pn) e efetiva (Pe). A análise de custos foi realizada através da determinação dos custos operacionais e de produção pelo método contábil. As operações foram avaliadas em diferentes condições de declividade, sentido de operação, distância de extração, presença de afloramento rochoso e classe de volume por tora, os quais também foram considerados como variáveis independes com intuito de se ajustar modelos matemáticos por regressão múltipla para a estimativa da produtividade, utilizando o procedimento Stepwise. Os principais resultados foram: para o primeiro desbaste a Pn foi de 10,90 m3/h e custo operacional total (COT) de 181,12 R$/he. Para o terceiro desbaste a Pn foi de 16,45 m3/h e COT de 185,58 R$/he. Em corte raso, para forwarder se obteve uma Pn de 29,05 m3/h e COT de 244,58 R$/he, enquanto que para o skidder se obteve uma Pn de 128,60 m3/h e COT de 218,31 R$/he. Para a modelagem da produtividade das máquinas, a distância e o volume por tora foram usadas como variáveis explicativas, estando presentes nas estimativas para o forwarder, além do volume por ciclo, em terceiro desbaste, e da declividade em primeiro desbaste e corte raso. Para o skidder, as variáveis utilizadas foram a distância e o volume por ciclo. Na etapa dois foi determinada a densidade economicamente ótima (DOE) e aceitável (DAE) para as diferentes situações de colheita. A DOE foi calculada pelo método indireto, sendo esta o produto do somatório dos custos de reconstrução, manutenção, extração e perda de área produtiva. Em primeiro desbaste a densidade de estradas atual (DE) foi de 45,28 m/ha, a DOE de 20,18 m/ha e a DAE de 28,26 m/ha. Em terceiro desbaste a DE foi de 95,08 m/ha, a DOE de 16,60 m/ha e a DAE de 21,68. Em corte raso a DE foi de 92,02 m/ha, sendo a DOE para o sistema CTL de 15,63 m/ha e DAE de 24,75 m/ha, enquanto que em sistema FT a DOE foi de 22,85 m/ha e DAE de 27,00 m/ha. De forma geral, a densidade de estradas atual foi acima da ótima e da aceitável, devendo ser realizado um replanejamento das operações visando uma malha viária dentro da densidade aceitável, resultando em menores custos e maiores receitas à empresa

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Santos, de Freitas Rafael Luiz. « MULTI-CAMERA SURVEILLANCE SYSTEM FOR TIME AND MOTION STUDIES OF TIMBER HARVESTING OPERATIONS ». UKnowledge, 2019. https://uknowledge.uky.edu/forestry_etds/48.

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Timber harvesting is an important activity in the state of Kentucky; however, there is still a lack of information about the procedure used by the local loggers. The stump to landing transport of logs with skidders is often the most expensive and time-consuming task in timber harvesting operations. This thesis evaluated the feasibility of using a multi-camera system for time and motion studies of timber harvesting operations. It was installed in 5 skidders in 3 different harvesting sites in Kentucky. The time stamped video provided accurate time consumption data for each work phase of the skidders, which was used to fit linear regressions and find the influence of skidding distance, skid-trail gradient, and load size on skidding time. The multi-camera systems were found to be a reliable tool for time and motion studies in timber harvesting sites. Six different time equations and two speed equations were fitted for skidding cycles and sections of skid-trails, for skidders that are both loaded and unloaded. Skid-trail gradient and load size did not have an influence on skidding time. There is a need for future studies of different variables that could affect skidding time and, consequently, cost.

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COELHO, MARIA C. C. « Restauração de Mata Ciliar pela viabilização de crédito de carbono : uma proposta sócio-ambiental para comunidade de baixa renda ». reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11570.

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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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Shirasawa, Hiroaki. « Modeling and simulation of operational forest planning in relation to road network layout, cable corridor layout and timber transportation ». Kyoto University, 2014. http://hdl.handle.net/2433/188759.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第18321号
農博第2046号
新制||農||1021(附属図書館)
学位論文||H26||N4828(農学部図書室)
31179
京都大学大学院農学研究科森林科学専攻
(主査)教授吉岡崇仁, 教授德地直子, 准教授長谷川尚史
学位規則第4条第1項該当

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Horton, Celeste Nichole. « Sediment Delivery Ratios and Areas of Forest Operational Features by Physiographic Groupings in the Southeastern U.S ». Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103884.

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Forests of the Southeastern United States produce approximately 12% of all the world's wood products and represent 40% of all U.S. timberland, thus emphasizing the importance of Southeast in support of the United States' role as the world's largest timber producer. Producing such quantities of timber requires a substantial areas of forest harvest operations, which have the potential to disturb soils, facilitate erosion and potentially reduce water quality. Harvest sites routinely contain operational features such as skid trails, harvest areas, haul roads, decks/landings and stream crossings, all of which have the potential to influence erosion and sediment deposition in streams. Forestry best management practices (BMPs) were created to minimize the effects of harvesting operations on sedimentation and are implemented at varying levels throughout the Southeastern U.S. We quantified the area of these features on 111 recent harvest sites throughout 11 Southeastern states and three physiographic groupings (Mountains, Piedmont, Coastal Plain). No significant differences were found between the groupings with regard to the percent of area occupied by each operational feature. Decks, haul roads, skid trails, and stream crossings comprised an average of 1.43%, 3.21%, 7.03%, and 0.19% of the harvest operations. Roads, decks, skid trails, and structures were combined into an access feature category. These combined access features occupied 13.0% of harvests in the Mountains, 10.2% in the Piedmont, and 10.4% in the Coastal Plain (10.4%). A companion study was developed to trap sediment delivered to the stream and quantify the sediment delivery ratios (SDRs) on a subset of harvests sites in order to determine the average amount of eroded material that could reach a stream from each specific operational feature following a harvest. Across all groupings, stream crossings had the highest average SDR (34.32%), while skid trails had the second highest SDR (21.04%). Substantial site variability resulted in large SDR differences with few meaningful significant differences, but stream crossings, skid trails, and haul roads had sufficiently high sediment delivery ratios across all groupings to warrant additional BMP focus on these areas.
Master of Science
The Southeastern United States is a major producer of forests and forest products, comprising about 40% of US timberland and 12% of global wood products. Support of this industry requires that over 4 million acres of forests are harvested annually across the southeastern U.S. and improper or under usage of forestry best management practices could result in soil erosion and subsequent transport to streams as sediment. Previous research indicates that different operational and access features found on logging sites have different erosion rates yet little data exists which document the percentages of erosion that is delivered as sediment to streams. Skid trails (trails that forestry equipment use within a harvesting operation) compromised the largest access feature average percent area (second to harvest area), followed by haul roads, then decks (area where equipment is kept and logs are processed and loaded), and finally stream crossings with the smallest average area. Stream crossings, skid trails and haul roads consistently had the highest average sediment delivery ratios for all groupings combined. However, substantial site variability resulted in large sediment delivery ratio differences with few meaningful significant differences.

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Odhiambo, Benedict O. « The use of time study, method study and GPS tracking in improving operational harvest planning in terms of system productivity and costs ». Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5333.

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Thesis (MScFor (Dept. of Forest and Wood Science)--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: This study aims to quantify the benefits of implementing an operational harvesting plan in forest harvesting operations. This is to be achieved by comparing productivity and costs from unplanned and planned harvesting operations. The study was conducted on a Pinus radiata plantation owned by Mountain to Ocean Forestry Company (Pty) Ltd (MTO) located near the town of Grabouw in the Western Cape Province of South Africa. MTO conducts harvesting operations using semi-mechanised tree-length harvesting systems. A wheeled H67 Clark Ranger cable skidder is used to extract tree-lengths from infield to the landing. Data was obtained both manually (work study) and from GPS tracking. Choking and dechoking data was obtained through time and method studies. GPS tracking was used to measure travel loaded and travel empty times, as well as travel distances and travel speeds. The aim of using both manual techniques and GPS tracking was to obtain detailed and spatially accurate information about the operation. The operating costs were estimated using South African Harvesting and Transport Costing Model. Productivity of the newly introduced tagline system (45.97 m³/pmh) exceeded that of mainline system (37.85 m³/pmhh) by 26%. The unit production cost of using tagline system (R20.21/m³) was 10% lower than the unit production cost of using mainline system (R22.54/³3). There were no benefits to be gained from improving the level of skid trail construction by removal of logging residue or cutting down stumps to as near the ground level as possible. A combination of manual (time and method studies) data collection and GPS tracking provided more detailed and accurate information on the semi-mechanised harvesting system.
AFRKAANSE OPSOMMING: Hierdie studie beoog om die voordele van die uitvoering van 'n operasionele inoestingsplan te kwantifiseer. Dit word bereik deur produktiwiteit en kostes van beplande en onbeplande inoestingswerksaamhede te vergelyk. Die studie is gedoen in Pinus radiata opstande van Mountain to Ocean Forestry Company (Pty) Ltd (MTO) naby Grabouw in die Wes-Kaap provinsie van Suid Afrika. MTO gebruik semi-gemeganiseerde boomlengte inoestingstelsels in hul inoestingswerksaamhede. . H67 Clark Ranger wielsleeptrekker met kabel en wenas is gebruik om boomlengtes van die veld na die pad te sleep. Data is versamel deur van beide hand (werkstudie) en GPS-opsporing gebruik te maak. Afhaak en aanhaak data is verkry deur van tyd- en metodestudies gebruik te maak. Gelaaide en ongelaaide tyd, spoed en afstande is met behulp van die GPS gemeet. Deur van beide hand en GPS versamelingsmetodes gebruik te maak, kon omvattende sowel as ruimtelik akkurate inligting oor die werksaamhede verkry word. Die bedryfskostes is verkry van die South African Harvesting and Transport Costing Model. Produktiwiteit van die nuut ingestelde verbindingslynstelsel (45.97 m³/pmh) het die hooflynstelsel (37.85 m³/pmh) met 26% oorskry. Die eenheidsproduksiekoste van die verbindingslynstelsel (R20.21/m³) was 10% laer as die eenheidsproduksiekoste van die hooflynstelsel (R22.54/m³). Daar was geen voordeel in die verbetering van die sleeppad konstruksie deur afval te verwyder of stompe nader aan die grondvlak af te sny nie. 'n Kombinasie van hand (tyd- en metodestudies) dataversameling en GPS-opsporing het meer akkurate en omvattende inligting oor die semi-gemeganiseerde inoestingstelsel verskaf.

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Mellberg, Anders. « Extension – Operator Environment for ForestHarvesters ». Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-21855.

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A forest harvester operator is today facing a stressful work environment with a high demand on coordination skills and effectiveness to run the operation with positive economical outcome. The learning phase is very long compared to similar work.The vision for this project was to transform the machine, through intuitive and innovative interface design, into an extension of the operator’s body. In this way it provides higher productivity as well as user friendliness, shorter learning phase and a healthier work situation.This was realized through the use of prior but yet not market available related research. Through market studies, applicable technology already available in other industries was found. The result is a complete seat with controls for a conceptual Gremo harvester realizable in the year 2023.

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Thèses sur le sujet « Forestry operation »

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