Articles de revues : « Forestry inventories »

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Strimbu, Bogdan M. « Comparing the efficiency of intensity-based forest inventories with sampling-error-based forest inventories ». Forestry : An International Journal of Forest Research 87, n^o 2 (15 janvier 2014) : 249–55. http://dx.doi.org/10.1093/forestry/cpt061.

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Thomas, Charles E., et John C. Rennie. « Combining Inventory Data for Improved Estimates of Forest Resources ». Southern Journal of Applied Forestry 11, n^o 3 (1 août 1987) : 168–71. http://dx.doi.org/10.1093/sjaf/11.3.168.

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Abstract Foresters occasionally have two or more estimates of the same volume, basal area, or other quantities of interest from independent inventories. A variety of statistical techniques for combining such estimates recently have begun to receive attention in surveys of census characteristics,agriculture, and forestry. Results from two independent timber resource inventories in Wayne County, Tennessee, are reported along with their respective sampling errors. Methods for combining estimates along with example calculations are presented and discussed. Suggestions are made for theapplication of this procedure to other sampling problems. South. J. Appl. For. 11(3):168-171.

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Holmström, Emma, Helena Gålnander et Magnus Petersson. « Within-Site Variation in Seedling Survival in Norway Spruce Plantations ». Forests 10, n^o 2 (19 février 2019) : 181. http://dx.doi.org/10.3390/f10020181.

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Seedling survival was evaluated from inventories of a large set of Norway spruce plantations in privately owned forests in southern Sweden. The inventories were conducted at the time of planting and a subset was re-inventoried three years later. This enabled comparison of regeneration success after soil scarification and planting. The acquired data enabled evaluation of annual and climatic variation of seedling mortality since inventories were made on newly established clearcuts distributed spatially throughout three regions in southern Sweden and repeated in five consecutive years. Within-site variation was also captured via the use of a large number of sample plots on each clearcut. To do so, thirty sample plots were established within weeks of planting on 150 clearcuts. Small- and large-scale site and management variables were recorded as well as the numbers of suitable planting spots and planted seedlings. Three years later, 60 of the initially surveyed clearcuts were revisited and the numbers of both planted and naturally regenerated seedlings counted. On average, 2000 seedlings ha−1 were planted and 1500 seedlings ha−1 had survived after three years. However, there was high variation, and in 42% of the revisited sample plots no mortality was recorded. Important variables for seedling survival identified by linear regression analysis included the number of suitable planting spots, soil moisture conditions and annual variation in available soil water.

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Hussendörfer, Erwin, Michael Köhl et Gerhard Müller-Starck. « Ein Beitrag zur Frage der repräsentativen Stichprobennahme bei genetischen Inventuren in Waldbaumpopulationen | A Contribution to the Precision of Sampling in Genetic Inventories of Forest Tree Populations ». Schweizerische Zeitschrift fur Forstwesen 150, n^o 6 (1 juin 1999) : 203–8. http://dx.doi.org/10.3188/szf.1999.0203.

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The precision of estimates of genetic inventories in dependency on the sample size and sample design is investigated by means of results of inventories within silver fir stands. Recommendations are derived about how to statistically verify results of genetic inventories.

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Moser, Paolo, Alexander C. Vibrans, Ronald E. McRoberts, Erik Næsset, Terje Gobakken, Gherardo Chirici, Matteo Mura et Marco Marchetti. « Methods for variable selection in LiDAR-assisted forest inventories ». Forestry 90, n^o 1 (19 août 2016) : 112–24. http://dx.doi.org/10.1093/forestry/cpw041.

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Pasalodos-Tato, Maria, Iciar Alberdi, Isabel Cañellas et Mariola Sánchez-González. « Towards assessment of cork production through National Forest Inventories ». Forestry : An International Journal of Forest Research 91, n^o 1 (3 octobre 2017) : 110–20. http://dx.doi.org/10.1093/forestry/cpx036.

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Fortin, Mathieu, Rubén Manso et Robert Schneider. « Parametric bootstrap estimators for hybrid inference in forest inventories ». Forestry : An International Journal of Forest Research 91, n^o 3 (22 novembre 2017) : 354–65. http://dx.doi.org/10.1093/forestry/cpx048.

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Abstract In forestry, the variable of interest is not always directly available from forest inventories. Consequently, practitioners have to rely on models to obtain predictions of this variable of interest. This context leads to hybrid inference, which is based on both the probability design and the model. Unfortunately, the current analytical hybrid estimators for the variance of the point estimator are mainly based on linear or nonlinear models and their use is limited when the model reaches a high level of complexity. An alternative consists of using a variance estimator based on resampling methods (Rubin, D. B. (1987). Multiple imputation for nonresponse surveys. John Wiley & Sons, Hoboken, New Jersey, USA). However, it turns out that a parametric bootstrap (BS) estimator of the variance can be biased in contexts of hybrid inference. In this study, we designed and tested a corrected BS estimator for the variance of the point estimator, which can easily be implemented as long as all of the stochastic components of the model can be properly simulated. Like previous estimators, this corrected variance estimator also makes it possible to distinguish the contribution of the sampling and the model to the variance of the point estimator. The results of three simulation studies of increasing complexity showed no evidence of bias for this corrected variance estimator, which clearly outperformed the BS variance estimator used in previous studies. Since the implementation of this corrected variance estimator is not much more complicated, we recommend its use in contexts of hybrid inference based on complex models.

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Vieira, Thiago Almeida, et Thomas Panagopoulos. « Urban Forestry in Brazilian Amazonia ». Sustainability 12, n^o 8 (16 avril 2020) : 3235. http://dx.doi.org/10.3390/su12083235.

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Urban forests provide multiple benefits in improving people’s lives and can be an important tool for achieving the goal of carbon neutral cities. In this study, we analyzed the diversity of plant species from urban forests in cities in the Brazilian Amazonia, based on data from scientific articles, through a systematic literature review. Our analysis revealed that 530 taxa, of which 479 were identified at the species level and 51 at the genus level, covering 38,882 individuals were distributed in 29 cities. The three most frequent species were Ficus benjamina, Mangifera indica, and Licania tomentosa. Exotic species were more frequent than native. The three most frequent species had almost 42% of the inventoried individuals. The choice of species has been made mainly by the local population, without monitoring by the public authorities. Recommendations for sustainable management of urban forests in Amazonia include investing in training of management bodies, periodic inventories, and awareness actions about the benefits of urban green infrastructure and on the advantages of native species. Policies for the sustainable management of urban green areas are necessary. The municipal governments must continuously monitor indicators of urban ecosystem services and provide financial resources for maintaining and increasing those area rates per person.

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Roesch, F. A., et P. C. Van Deusen. « Anomalous diameter distribution shifts estimated from FIA inventories through time ». Forestry 83, n^o 3 (7 avril 2010) : 269–76. http://dx.doi.org/10.1093/forestry/cpq009.

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McPherson, E. Gregory, James McCarter et Fred Baker. « A Microcomputer-Based Park Tree Inventory System ». Arboriculture & ; Urban Forestry 11, n^o 6 (1 juin 1985) : 177–81. http://dx.doi.org/10.48044/jauf.1985.040.

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Many communities have special parks that contain trees which receive as much or more care than do most street trees. Planning and managing vegetation in these areas is complex and can benefit from use of computerized tree inventory systems. This report outlines how park trees can be located and inventoried using a coordinate grid system. It also describes a computer program for park tree inventories designed to operate on a microcomputer, and field tested at the State Arboretum of Utah in Logan.

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Saborowski, J., et J. Cancino. « About the benefits of poststratification in forest inventories ». Journal of Forest Science 53, No. 4 (7 janvier 2008) : 139–48. http://dx.doi.org/10.17221/2171-jfs.

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A large virtual population is created based on the GIS data base of a forest district and inventory data. It serves as a population where large scale inventories with systematic and simple random poststratified estimators can be simulated and the gains in precision studied. Despite their selfweighting property, systematic samples combined with poststratification can still be clearly more efficient than unstratified systematic samples, the gain in precision being close to that resulting from poststratified over simple random samples. The poststratified variance estimator for the conditional variance given the within strata sample sizes served as a satisfying estimator in the case of systematic sampling. The differences between conditional and unconditional variance were negligible for all sample sizes analyzed.

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Smiley, E. Thomas, et Fred Baker. « Options in Street Tree Inventories ». Arboriculture & ; Urban Forestry 14, n^o 2 (1 février 1988) : 36–42. http://dx.doi.org/10.48044/jauf.1988.010.

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Many options are available for street tree inventories to meet the unique needs and budgets of most municipalities. Goals and objectives must be clearly defined, type and longevity of inventory decided on, and data collection specifications clearly developed. The purpose and size of the inventory will determine whether to computerize the information. Available options are outlined and discussed.

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Noordermeer, Lennart, Roar Økseter, Hans Ole Ørka, Terje Gobakken, Erik Næsset et Ole Martin Bollandsås. « Classifications of Forest Change by Using Bitemporal Airborne Laser Scanner Data ». Remote Sensing 11, n^o 18 (14 septembre 2019) : 2145. http://dx.doi.org/10.3390/rs11182145.

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Changes in forest areas have great impact on a range of ecosystem functions, and monitoring forest change across different spatial and temporal resolutions is a central task in forestry. At the spatial scales of municipalities, forest properties and stands, local inventories are carried out periodically to inform forest management, in which airborne laser scanner (ALS) data are often used to estimate forest attributes. As local forest inventories are repeated, the availability of bitemporal field and ALS data is increasing. The aim of this study was to assess the utility of bitemporal ALS data for classification of dominant height change, aboveground biomass change, forest disturbances, and forestry activities. We used data obtained from 558 field plots and four repeated ALS-based forest inventories in southeastern Norway, with temporal resolutions ranging from 11 to 15 years. We applied the k-nearest neighbor method for classification of: (i) increasing versus decreasing dominant height, (ii) increasing versus decreasing aboveground biomass, (iii) undisturbed versus disturbed forest, and (iv) forestry activities, namely untouched, partial harvest, and clearcut. Leave-one-out cross-validation revealed overall accuracies of 96%, 95%, 89%, and 88% across districts for the four change classifications, respectively. Thus, our results demonstrate that various changes in forest structure can be classified with high accuracy at plot level using data from repeated ALS-based forest inventories.

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Kjeldsen-Kragh Keller, Julie, et Cecil Konijnendijk. « Short Communication : A Comparative Analysis of Municipal Urban Tree Inventories of Selected Major Cities in North America and Europe ». Arboriculture & ; Urban Forestry 38, n^o 1 (1 janvier 2012) : 24–30. http://dx.doi.org/10.48044/jauf.2012.005.

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Effective management of the urban forest calls for municipalities to have a tree inventory of their urban resource. The approach to urban forestry is rather different in Europe and North America, both in terms of background and culture. This contribution discusses similarities and differences in tree inventory practices, based on a pilot study of three major cities in North America (Toronto, Ontario, Canada; and Boston, Massachusetts and New York City, New York, U.S.) and three major cities in Northern Europe (Oslo, Norway; and Aarhus and Copenhagen, Denmark). The pilot study consisted of semi-structured expert interviews in each city, and an analysis of their tree inventories in terms of their level of detail, how they were undertaken, and how they have been used. Each of the cities, with exception of Oslo, had inventoried all of their street trees. Volunteers were only used in Boston and New York City. None of the cities had developed a management plan based on their tree inventory. The inventory had only been completely incorporated into the work order system in New York City and Toronto. This explorative study shows that more research is needed to investigate what subsequently happens to tree inventories in municipalities after they have been performed. Moreover, more work is needed to identify whether inventories are being utilized to their full advantage in terms of producing management plans. Some key themes for further research are described. The set up of this pilot study could serve as a format for comprehensive research.

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Ries, Paul, A. Scott Reed et Sarah Kresse. « The Impact of Statewide Urban Forestry Programs : A Survey of Cities in Oregon, U.S. » Arboriculture & ; Urban Forestry 33, n^o 3 (1 mai 2007) : 168–75. http://dx.doi.org/10.48044/jauf.2007.019.

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All 50 U.S. states have a state urban forestry program that provides assistance to cities. Statewide surveys of city urban forestry leaders are a common tool for assessing urban forestry needs and accomplishments. Oregon has conducted two such comprehensive surveys, in 1992 and 2004. The 2004 survey was designed to gain insight into the scope and extent of the urban forest resource in Oregon to measure local program accomplishment since 1992 and to measure the impact of a statewide urban forestry assistance program. The survey had a return rate of 51%, and the results show differences among small, medium, and large communities. Results show that Oregon cities have made significant gains in urban forest management over the last 12 years. The data reveal insights of local urban foresters relative to tree-related issues and outcomes of local efforts. This research illustrates the impact a state urban forestry assistance program can have on local program accomplishment. Oregon cities that have received state assistance are more likely to have urban forestry program components such as tree ordinances and inventories, are more likely to be Tree City USA communities, and are more likely to be investing in urban forestry activities.

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Bāders, Endijs, Oskars Krišāns, Jānis Donis, Didzis Elferts, Ieva Jaunslaviete et Āris Jansons. « Norway Spruce Survival Rate in Two Forested Landscapes, 1975–2016 ». Forests 11, n^o 7 (9 juillet 2020) : 745. http://dx.doi.org/10.3390/f11070745.

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The increasing frequency and severity of natural disturbances (e.g., storms and insect outbreaks) due to climate change are expected to reduce the abundance of Norway spruce stands in the European forests. Under such conditions, the assessment of status quo on focusing on survival of Norway spruce stands are essential for the agility of forest management strategies. The dynamics (mortality rate) of Norway spruce stands in hemiboreal forests based on forest inventories for the period from 1975 to 2016 (inventories of 1975, 1985, 1999, 2011 and 2016) were analyzed in two forest landscapes in the western and eastern parts of Latvia (Vane and Dviete, respectively). The spatiotemporal changes in age-dependent mortality differing by abundance of Norway spruce and disturbance regime were assessed, focusing on the transitions of stands between age groups (inventories). The age-related changes in probability of stands transitioning into the next age group contrasted (p < 0.001) between sites. In Vane, the survival of stands between inventories was constant (ca. 90%), while in Dviete, it decreased sharply from 85.7% during 1985–1999 inventories to 49.3% in 2011–2016. Age-related decreases in stand survival showed local dependencies between both landscapes, namely, in Vane, notable decreases started from 61 years, while in Dviete, the downward trends started already from 31 years, probably due to different disturbance regimes. This suggests that, in forest management planning, the different outcomes for mortality patterns between both landscapes must be considered and should not be generalized for a whole country.

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Duntemann, Mark, Thomas Gargrave et John Andresen. « Community Forestry Initiatives ». Arboriculture & ; Urban Forestry 14, n^o 4 (1 avril 1988) : 90–93. http://dx.doi.org/10.48044/jauf.1988.022.

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Thirty-seven municipal governments of the northern Illinois Little Calumet Watershed (LCW) consortium have joined to promote a unified urban forestry program. A combination of business and bedroom communities, LCW includes 132,975 acres and is populated by 541,200 urbanites. In concert with the urban forestry components of the U.S.D.A. Forest Service, the State of Illinois Department of Conservation, and the University of Illinois, the municipalities have, in 1987, started a number of community forestry educational and outreach programs. Led by the provisional LCW Urban Forestry Council, the consortium, headquartered in Chicago Heights, is now computerizing initial, municipal tree inventories. Ordinances which shall enhance the conservation and planting of community owned trees are also in preparation. In addition the Council is promoting Tree City USA initiatives and formulating urban forest management plans.

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Gillis, M. D. « Estimating Change from Successive Static Forest Inventories ». Forestry Chronicle 64, n^o 4 (1 août 1988) : 352–54. http://dx.doi.org/10.5558/tfc64352-4.

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Most Canadian forest inventories are designed to obtain information about forest resources at a specific point in time, i.e., static information. In recent years there has emerged a requirement for information on changes over time of the forest resource. One potential for getting such information is to compare data from successive (static) inventories. However, as shown in this paper, such changes are frequently artifacts of different procedures. Since real changes in forest resources may be masked by artificial differences, such comparison is discouraged and should not be done without detailed background knowledge.

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Rahlf, Johannes, Johannes Breidenbach, Svein Solberg, Erik Næsset et Rasmus Astrup. « Digital aerial photogrammetry can efficiently support large-area forest inventories in Norway ». Forestry : An International Journal of Forest Research 90, n^o 5 (15 juin 2017) : 710–18. http://dx.doi.org/10.1093/forestry/cpx027.

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Morck, Randall, Eduardo Schwartz et David Stangeland. « The Valuation of Forestry Resources Under Stochastic Prices and Inventories ». Journal of Financial and Quantitative Analysis 24, n^o 4 (décembre 1989) : 473. http://dx.doi.org/10.2307/2330980.

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Titus, Stephen J., et Robert T. Morton. « Forest Stand Growth Models : What For ? » Forestry Chronicle 61, n^o 1 (1 février 1985) : 19–22. http://dx.doi.org/10.5558/tfc61019-1.

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Until very recently foresters have relied on infrequent inventories to provide static descriptions of large forest areas for management planning. With the quantum increases in computing power, the massing of forestry data, and the increasing pressure for effective management planning, it is becoming necessary to view the forest as dynamic, and subject to manipulation for management purposes. Prediction of changes to forest structure and yield must be made to update old data and project stands into the future. This paper reviews the current sources of literature on growth and yield, discusses basic types and components of growth models, and gives some examples of important uses for growth and yield models. The future will see increased use of computers for analysis of forestry data including even more sophisticated growth and yield models linked to both inventory and decision making processes.

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Gillis, Mark D., Stephen L. Gray, Dennis Clarke et Katja Power. « Canada's National Forest Inventory : What can it tell us about old growth ? » Forestry Chronicle 79, n^o 3 (1 juin 2003) : 421–28. http://dx.doi.org/10.5558/tfc79421-3.

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Canada's National Forest Inventory is a periodic compilation of existing inventory information from across the country. The main sources of information are detailed, stand-level descriptions contained in provincial, territorial, and industrial management-level inventories. Typical management inventories do not identify old growth as a specific attribute. Therefore, the National Forest Inventory, based on management-level inventories, does not specifically show old growth. Indicators of old growth, such as stand age and maturity, are contained in the national inventory and are analysed to illustrate the distribution of forest in Canada by age and maturity. A further analysis by selected species is also provided. Finally, a new plot-based national inventory that will provide additional old-growth indicators is discussed. Key words: forest inventory, inventory attributes, old growth, old-growth indicators, NFI, CanFI, EOSD

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Sterba, H. « Forest inventories and growth models to examine management strategies for forests in transition ». Forestry 75, n^o 4 (1 avril 2002) : 411–18. http://dx.doi.org/10.1093/forestry/75.4.411.

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Koch, Barbara. « Stand und Perspektiven der Nutzung neuer Fernerkundungstechnologien im Waldbereich | Status and perspectives of the application of new remote sensing technologies in forestry ». Schweizerische Zeitschrift fur Forstwesen 162, n^o 6 (1 juin 2011) : 156–63. http://dx.doi.org/10.3188/szf.2011.0156.

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Remote sensing has been used in forestry for a long time. Aerial photography has mainly been used to support national and operational inventories and medium resolution satellite data for large area inventories. Today through the availability of new technologies there are greatly extended possibilities for remote sensing in the forestry sector. The major change is the better availability of 3-D information, which allows a much better modelling of forests and forest attributes. The paper presents an overview of the newest remote sensing technologies, such as the systems carried by satellite which can be used to record changes or degradation in the area covered by forest for the global forestry resources assessment of the UN World Food and Agriculture Organisation or are examined in connection with the United Nations REDD program. Besides these, other small scale applications are presented based on optical or laser systems carried by aircraft. The article finishes with an outlook on expected developments in the near future. It is expected that the future of forestry remote sensing will be characterized above all by the combination of information obtained from diverse sources, such as data based on terrestrial and on remotely sensed sources.

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Medina-Tello, Carlos, José Luis Martínez-Alcantar, Carlos Alfredo Díaz-González et Luis Tonatiuh Castellanos-Serrano. « Experiencias en forestrónica, agromática y agrónica, desde el quehacer del cuerpo académico ITZIT-CA-3 TECNM y CIISCINASYC de la Universidad Autónoma Chapingo ». e-CUCBA 10, n^o 19 (22 décembre 2022) : 151–58. http://dx.doi.org/10.32870/ecucba.vi19.274.

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Forestonic engineering through a new concept in agricultural, forestry and mechatronic sciences was defined. Forestronicengineering includes the use of telecommunications, computer services, mechanics and electronics, applied jointly to forestry andthe forestry industry, from forests to their reforestation and use, both in forestry and in production and management. of resources.forestry, furniture manufacturing and logistics. Some concrete examples of the wide utility of Forestrónica are: automated controlof forest nurseries, forest satellite geopositioning for forest management, automatic registration of forest inventories with mappingof timber yields and processing of satellite images and UAV ́s.

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Bonnor, G. M., et S. Magnussen. « Forest Inventories in Canada : A Framework for Change ». Forestry Chronicle 63, n^o 3 (1 juin 1987) : 193–98. http://dx.doi.org/10.5558/tfc63193-3.

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A forest inventory System for the acquisition of static and dynamic data, as well as for inventory updating, is developed and demonstrated.In the system, a conventional management type of inventory is completed every 20 years to obtain static data. Some or all sample plots are permanent. Every five years, the area changes are mapped and compiled. These changes include additions and deletions of forest areas as well as changes in the existing forest due to harvesting, forest fires, and other disturbances. Also, plots are remeasured to estimate volume growth on the undisturbed areas and volume losses on the disturbed areas. Finally, the area and volume change data are applied to the initial static inventory to produce updated inventory figures.As an example, the system was applied to an area of mixedwood forests in the upper Ottawa Valley. The results indicate that the system is practical and yields useful summaries.

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Schreuder, Hans T., et G. M. Bonnor. « Forest Inventories in the United States and Canada ». Forestry Chronicle 63, n^o 6 (1 décembre 1987) : 431–34. http://dx.doi.org/10.5558/tfc63431-6.

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Canadian and United States (U.S.) extensive forest inventories are contrasted. The Canadians have had more experience in mapping and remote sensing; the U.S., in collecting, handling, and reporting change data. Development of common standards, terms, and definitions, as well as a common forest and land classification system, would facilitate cooperation and exchange of information.

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Vidal, Claude, Iciar Alberdi, John Redmond, Martin Vestman, Adrian Lanz et Klemens Schadauer. « The role of European National Forest Inventories for international forestry reporting ». Annals of Forest Science 73, n^o 4 (18 avril 2016) : 793–806. http://dx.doi.org/10.1007/s13595-016-0545-6.

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Castilla, Guillermo, Jennifer Hird, Bryce Maynes, Doug Crane, John Cosco, Jim Schieck et Greg McDermid. « Broadening modern resource inventories : A new protocol for mapping natural and anthropogenic features ». Forestry Chronicle 89, n^o 05 (octobre 2013) : 681–89. http://dx.doi.org/10.5558/tfc2013-121.

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Conventional forests inventories narrowly focus on timber attributes and often neglect other aspects that may be relevant for other purposes. In an effort to broaden the usefulness of these inventories, we introduce a new protocol based on softcopy photo-interpretation for efficiently capturing both natural and anthropogenic features across a variety of landscapes. Salient aspects of this protocol include (1) the combined use of polygon, point and line feature representation; (2) over 50 fields per attribute table; and (3) semi-automated quality control tools. We show an application example over a 3-km by 7-km sample area in central-eastern Alberta.

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Wulder, M. A., R. S. Skakun, S. E. Franklin et J. C. White. « Enhancing forest inventories with mountain pine beetle infestation information ». Forestry Chronicle 81, n^o 1 (1 février 2005) : 149–59. http://dx.doi.org/10.5558/tfc81149-1.

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Polygon decomposition is an approach for integrating different data sources within a GIS. We use this approach to understand the impacts associated with mountain pine beetle red attack. Three different sources of red attack information are considered: aerial overview sketch mapping, helicopter GPS surveys, and Landsat imagery. Existing inventory polygons are augmented with estimates of the proportion and area of red attack damage. Although differences are found in the area of the infestation, the affected forest stands have similar characteristics. Polygon decomposition adds value to existing forest inventories through update and the incorporation of new attributes applicable to forest management. Key words: polygon decomposition, forest inventory, GIS, mountain pine beetle, red attack, remote sensing, Landsat

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Sterba, H. « Diversity indices based on angle count sampling and their interrelationships when used in forest inventories ». Forestry 81, n^o 5 (25 avril 2008) : 587–97. http://dx.doi.org/10.1093/forestry/cpn010.

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Magnussen, Steen. « A method for enhancing tree species proportions from aerial photos ». Forestry Chronicle 73, n^o 4 (1 août 1997) : 479–87. http://dx.doi.org/10.5558/tfc73479-4.

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Data on tree species richness of forests are needed for sustainable management. Photo interpreted data is a mainstay of forest inventories in Canada but is known to simplify the species composition of stands in accordance with the objective of providing stand descriptors. Species proportions estimated from aerial photos will often deviate significantly from ground based sample estimates. More tree species are usually found in the latter. To enhance photo-interpreted species proportions to better match ground observations this study proposes a cross-correlation memory matrix model as the most promising approach to a notoriously difficult problem. Ground and photo data from 246 stands in three sites in coastal BC were used for model estimation and validation. Enhanced photo-based tree species proportions were, in most stands, closer to the ground estimates than the raw estimates. Changes in species proportions due to enhancement appeared reasonable when considering the actual species mix and stand structures. Two popular indices of species richness derived from photo proportions were biased downward. The proposed method effectively reduced the bias in one index. The model is easy to implement in operational inventories. Key words: photo interpretation, tree species proportions, forest inventories, matrix model

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Kelsey, P. D., et R. G. Hootman. « Soil and Tree Resource Inventories for Campus Landscapes ». Arboriculture & ; Urban Forestry 14, n^o 10 (1 octobre 1988) : 243–49. http://dx.doi.org/10.48044/jauf.1988.058.

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A soil resource and tree inventory of the Northwestern University, Evanston, Illinois campus was undertaken to develop management strategies for maintaining mature oak groves in an urbanized environment. The inventory used biological, physical, and chemical methods to evaluate the campus landscape. This integrative approach provides a comprehensive landscape evaluation as the basis for long range planning.

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Korboulewsky, Nathalie, Isabelle Bilger et Abdelwahab Bessaad. « How to Evaluate Downed Fine Woody Debris Including Logging Residues ? » Forests 12, n^o 7 (6 juillet 2021) : 881. http://dx.doi.org/10.3390/f12070881.

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Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest inventories and ecological studies because they are unbiased and accurate methods. Nevertheless, most studies and inventories take into account only coarse woody debris (CWD, >10 cm in diameter), although fine woody debris (FWD) can account for a large part of the total downed biomass. We compared the LIS and FAS methods for FWD volume or biomass estimates and evaluated the influence of diameter and wood density measurements, plot number and size. We used a Test Zone (a defined surface area where a complete inventory was carried out, in addition to FAS and LIS), a Pilot Stand (a forest stand where both LIS and FAS methods were applied) and results from 10 field inventories in deciduous temperate forest stands with various conditions and amounts of FWD. Both methods, FAS and LIS, provided accurate (in trueness and precision) volume estimates, but LIS proved to be the more efficient. Diameter measurement was the main source of error: using the mean diameter, even by diameter class, led to an error for volume estimates of around 35%. On the contrary, wood density measurements can be simplified without much influence on the accuracy of biomass estimates (use of mean density by diameter class). We show that the length and number of transects greatly influences the estimates, and that it is better to apply more, shorter transects than fewer, longer ones. Finally, we determined the optimal methodology and propose a simplification of some measurements to obtain the best time-precision trade-off for FWD inventories at the stand level.

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Barrett, T. M. « Optimizing efficiency of height modeling for extensive forest inventories ». Canadian Journal of Forest Research 36, n^o 9 (1 septembre 2006) : 2259–69. http://dx.doi.org/10.1139/x06-128.

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Although critical to monitoring forest ecosystems, inventories are expensive. This paper presents a generalizable method for using an integer programming model to examine tradeoffs between cost and estimation error for alternative measurement strategies in forest inventories. The method is applied to an example problem of choosing alternative height-modeling strategies for 1389 plots inventoried by field crews traveling within an 82.5 × 106 ha region of the west coast of North America during one field season. In the first part of the application, nonlinear regional height models were constructed for 38 common species using a development data set of 137 374 measured tree heights, with root mean square error varying from 6.7 to 2.1 m. In the second part of the application, alternative measurement strategies were examined using a minimal cost objective subject to constraints on travel time and estimation error. Reduced travel time for field crews can be a significant portion of the cost savings from modeling tree heights. The optimization model was used to identify a height-modeling strategy that, given assumptions made, resulted in <10% of maximum average plot volume error, >33% of potential measurement cost savings, and small bias for estimates of regional volume and associated sampling error (0.1% and 0.4%, respectively).

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Mathys, A. S., A. Bottero, G. Stadelmann, E. Thürig, M. Ferretti et C. Temperli. « Presenting a climate-smart forestry evaluation framework based on national forest inventories ». Ecological Indicators 133 (décembre 2021) : 108459. http://dx.doi.org/10.1016/j.ecolind.2021.108459.

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Corona, P., et M. Marchetti. « Outlining multi-purpose forest inventories to assess the ecosystem approach in forestry ». Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology 141, n^o 2 (juillet 2007) : 243–51. http://dx.doi.org/10.1080/11263500701401836.

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Kilham, Philipp, Gerald Kändler, Christoph Hartebrodt, Anne-Sophie Stelzer et Ulrich Schraml. « Designing Wood Supply Scenarios from Forest Inventories with Stratified Predictions ». Forests 9, n^o 2 (6 février 2018) : 77. http://dx.doi.org/10.3390/f9020077.

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Scheuber, Matthias, Michael Köhl et Berthold Traub. « Forstliche Inventur als Planungsgrundlage für die Forstwirtschaft Kirgistans | Planning Kyrgyzstan's Forestry on the Basis of Forest Inventories ». Schweizerische Zeitschrift fur Forstwesen 151, n^o 3 (1 mars 2000) : 75–79. http://dx.doi.org/10.3188/szf.2000.0075.

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The independence of Kyrgyzstan brings with it the need to rethink the organization of the whole forestry sector. Information is now required which cannot be gathered from current records, due to the unorthodox methods used to gather data in the past. As part of the Kyrgyz-Swiss Forestry Support Program, the Chair for Forest Biometrics and Computer Sciences of Dresden University of Technology and the Swiss Federal Institute (WSL) are therefore developing tailor-made methods of compiling sample-based forest inventories on a national and forest enterprise level. Concentric circles are used as the sample unit; on a national level, these are combined to produce clusters of three trial plots. They are distributed using a systematic dot grid with varying density according to the level of assessment (national or forest enterprise) and forest type. The parameters in the catalogue, definitions and measurement rules are harmonized. An operational forest definition allows the results to be compared with international studies. The production of maps and the implementation of a GIS are essential for both inventories. Current conditions in the country make the development of these methods difficult;despite this, the work should be completed by the end of the year 2000.

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Westinga, E., A. Mukashema et H. van Gils. « A comparison of fine resolution census and image-based national forest inventories : a case study of Rwanda ». Forestry 86, n^o 4 (24 juin 2013) : 453–61. http://dx.doi.org/10.1093/forestry/cpt016.

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Pohjankukka, Jonne, Sakari Tuominen et Jukka Heikkonen. « Bayesian Approach for Optimizing Forest Inventory Survey Sampling with Remote Sensing Data ». Forests 13, n^o 10 (14 octobre 2022) : 1692. http://dx.doi.org/10.3390/f13101692.

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In large-area forest inventories, a trade-off between the amount of data to be sampled and the corresponding collection costs is necessary. It is not always possible to have a very large data sample when dealing with sampling-based inventories. It is therefore important to optimize the sampling design with the limited resources. Whereas this sort of inventories are subject to these constraints, the availability of remote sensing (RS) data correlated with the forest inventory variables is usually much higher. For this reason, the RS and sampled field measurement data are often used in combination for improving the forest inventory estimation. In this study, we propose a model-based data sampling method founded on Bayesian optimization and machine learning algorithms which utilizes RS data to guide forest inventory sample selection. We evaluate our method in empirical experiments using real-world volume of growing stock data from the Aland region in Finland. The proposed method is compared against two baseline methods: simple random sampling and the local pivotal method. When a suitable model link is selected, the empirical experiments show on best case on average up to 22% and 79% improvement in population mean and variance estimation respectively over baselines. However, the results also illustrate the importance of model selection which has a clear effect on the results. The novelty of the study is in the application of Bayesian optimization in national forest inventory survey sampling.

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Ehlers, Sarah, Anton Grafström, Kenneth Nyström, Håkan Olsson et Göran Ståhl. « Data assimilation in stand-level forest inventories ». Canadian Journal of Forest Research 43, n^o 12 (décembre 2013) : 1104–13. http://dx.doi.org/10.1139/cjfr-2013-0250.

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The development of remote sensing methods through research and large-scale application nowadays makes it possible to obtain stand-level estimates of forest variables at short intervals and at low cost. This offers substantial possibilities to forestry practitioners, but it also poses challenges regarding how cost-efficient data acquisition strategies should be developed. For example, should cheap but low-quality data be acquired and discarded whenever new data become available or should investments be made in high-quality data that are continuously updated to last over a longer period of time? We suggest that the solution could be to establish data assimilation (DA) procedures linked to forest inventories to make appropriate use of data from several sources. With DA, old information is updated through growth forecasts and when new information becomes available it is assimilated with the old information; the different sources of information are made use of to the extent motivated by their accuracy. In this study we made a general assessment of the usefulness of DA in connection with stand-level forest inventories and we compared two different methodological approaches, the extended Kalman filter and the Bayesian method. Not surprisingly, the relative advantage of DA was found to be largest for cases where low-precision estimates of growing stock volume were obtained at short intervals and forecasts were made with accurate growth prediction models. The methodological comparison revealed a tendency of the extended Kalman filter to underestimate the variance of the estimates.

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Ramezani, Habib, et Alireza Ramezani. « Forest fragmentation assessment using field-based sampling data from forest inventories ». Scandinavian Journal of Forest Research 36, n^o 4 (1 avril 2021) : 289–96. http://dx.doi.org/10.1080/02827581.2021.1908592.

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Kilham, Philipp, Christoph Hartebrodt et Gerald Kändler. « Generating Tree-Level Harvest Predictions from Forest Inventories with Random Forests ». Forests 10, n^o 1 (31 décembre 2018) : 20. http://dx.doi.org/10.3390/f10010020.

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Wood supply predictions from forest inventories involve two steps. First, it is predicted whether harvests occur on a plot in a given time period. Second, for plots on which harvests are predicted to occur, the harvested volume is predicted. This research addresses this second step. For forests with more than one species and/or forests with trees of varying dimensions, overall harvested volume predictions are not satisfactory and more detailed predictions are required. The study focuses on southwest Germany where diverse forest types are found. Predictions are conducted for plots on which harvests occurred in the 2002–2012 period. For each plot, harvest probabilities of sample trees are predicted and used to derive the harvested volume (m³ over bark in 10 years) per hectare. Random forests (RFs) have become popular prediction models as they define the interactions and relationships of variables in an automatized way. However, their suitability for predicting harvest probabilities for inventory sample trees is questionable and has not yet been examined. Generalized linear mixed models (GLMMs) are suitable in this context as they can account for the nested structure of tree-level data sets (trees nested in plots). It is unclear if RFs can cope with this data structure. This research aims to clarify this question by comparing two RFs—an RF based on conditional inference trees (CTree-RF), and an RF based on classification and regression trees (CART-RF)—with a GLMM. For this purpose, the models were fitted on training data and evaluated on an independent test set. Both RFs achieved better prediction results than the GLMM. Regarding plot-level harvested volumes per ha, they achieved higher variances explained (VEs) and significantly (p < 0.05) lower mean absolute residuals when compared to the GLMM. VEs were 0.38 (CTree-RF), 0.37 (CART-RF), and 0.31 (GLMM). Root means squared errors were 138.3, 139.9 and 145.5, respectively. The research demonstrates the suitability and advantages of RFs for predicting harvest decisions on the level of inventory sample trees. RFs can become important components within the generation of business-as-usual wood supply scenarios worldwide as they are able to learn and predict harvest decisions from NFIs in an automatized and self-adapting way. The applied approach is not restricted to specific forests or harvest regimes and delivers detailed species and dimension information for the harvested volumes.

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Knechtle, Norbert. « Materialprofile von Holzerntesystemen als Ausgangspunkt für Ökoinventare | Material Profiles of Timber-Harvesting Systems as a Basis for Life Cycle Inventories ». Schweizerische Zeitschrift fur Forstwesen 150, n^o 3 (1 mars 1999) : 81–87. http://dx.doi.org/10.3188/szf.1999.0081.

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A Life Cycle Assessment (LCA), based on life cycle inventories, is proposed to evaluate the eco-efficiency of timber harvesting systems. A comparison is made between timber harvesting productivity and the consumption of environment during the different stages of timber harvesting.

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Hébert, Rémi. « Méthodologie pour l'analyse des données forestières historiques : le cas de la forêt expérimentale du Lac Édouard, Québec ». Forestry Chronicle 80, n^o 4 (1 août 2004) : 469–72. http://dx.doi.org/10.5558/tfc80469-4.

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Permanent sampling plots in experimental forests have generated large quantities of data over the past decades. Methods used to collect certain of these data have often varied over the course of the sampling. The objective of this study was to develop a process to evaluate sampling differences in historical forest data. The proposed approach is to: (1) examine available data and seek out the missing ones in archives of the concerned organizations; (2) regroup data by inventory periods; (3) search for the sampling methodology in each of the different inventory periods; and (4) evaluate the impact of differences in methodology on data continuity. When using this approach on the historical data of the Lake Edward experimental forest, we were able to better define the strengths and the weaknesses of the database. Key words: forest inventories, La Mauricie National Park, permanent sample plots, regeneration inventories

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Muller, Robert, et Carol Bornstein. « Maintaining the Diversity of California’s Municipal Forests ». Arboriculture & ; Urban Forestry 36, n^o 1 (1 janvier 2010) : 18–27. http://dx.doi.org/10.48044/jauf.2010.003.

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Policies to promote urban forest diversity were assessed in 49 California, U.S. municipalities through a short questionnaire, followed by evaluation of street tree inventories and approved planting lists. While the majority of respondents (82%) indicated maintaining species diversity was an objective in managing their municipal forest, fewer than half of those responding positively (48%) had codified the objective in an actual urban forest management plan. Protecting against invasive species was an objective for a minority of communities (24%). Street tree inventories, provided by 18 respondents, indicated a high existing diversity within the communities of the state of California (avg. 185 species per community; range 95–408). In communities where both inventories and approved planting lists could be compared directly, the number of approved species for future planting was 29% of the number of species in the existing inventory. This suggests that the future diversity of California’s urban forests may be at risk. In order to improve diversity of their municipal forests, it is suggested communities retain an experimental approach to evaluating new species, build productive collaborations with all stakeholders as well as other communities, and develop outreach opportunities to enhance public awareness of the multiple values of a diverse urban forest.

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Sáez-Cano, Guadalupe, Marcos Marvá, Paloma Ruiz-Benito et Miguel A. Zavala. « Modelling Tree Growth in Monospecific Forests from Forest Inventory Data ». Forests 12, n^o 6 (8 juin 2021) : 753. http://dx.doi.org/10.3390/f12060753.

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The prediction of tree growth is key to further understand the carbon sink role of forests and the short-term forest capacity on climate change mitigation. In this work, we used large-scale data available from three consecutive forest inventories in a Euro-Mediterranean region and the Bertalanffy–Chapman–Richards equation to model up to a decade’s tree size variation in monospecific forests in the growing stages. We showed that a tree-level fitting with ordinary differential equations can be used to forecast tree diameter growth across time and space as function of environmental characteristics and initial size. This modelling approximation was applied at different aggregation levels to monospecific regions with forest inventories to predict trends in aboveground tree biomass stocks. Furthermore, we showed that this model accurately forecasts tree growth temporal dynamics as a function of size and environmental conditions. Further research to provide longer term prediction forest stock dynamics in a wide variety of forests should model regeneration and mortality processes and biotic interactions.

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Barbezat, Vincent. « Analyse semi-automatisée de photos aériennes numérisées pour l'étude de la dynamique de peuplements arborescents | Semi-Automatised Analysis of Digitised Aerial Photographs for the Study of Arborescent Population Dynamics ». Schweizerische Zeitschrift fur Forstwesen 151, n^o 7 (1 juillet 2000) : 238–42. http://dx.doi.org/10.3188/szf.2000.0238.

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At the present time, landscape inventories, the third National Forest Inventory (NFI), permanent research plots in the forests,cantonal inventories, regional forest planning, the redefinition of useful farm land, a new inventory of standard tree orchards but also the protection of peat bog and alluvial areas are daily business. Therefore, the development of a software for automated aerial photograph analysis is of greatest interest to the Swiss Confederation and its cantons as well as to forest owners, research institutes and certain industries (private engineering enterprises, software producers). In answer to these expectations, the Antenne Romande WSL, together with the Institute of Production in Microengineering of the Swiss Federal Institute of Technology Lausanne(EPFL), proposes to develop a software for user-friendly, neutral and rapid image-processing, the working precision of which will suit forest and landscape managers. Moreover, the software will provide scientists with basic data for the modelling of various ecosystem processes.

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Combe, Jean. « Valorisation de la ressource ligneuse en Suisse : à la recherche d’une valeur ajoutée pour les feuillus | Valorisation of Swiss Timber Resources : Seeking Added Value for Hardwood ». Schweizerische Zeitschrift fur Forstwesen 151, n^o 7 (1 juillet 2000) : 243–46. http://dx.doi.org/10.3188/szf.2000.0243.

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The evolution of the proportion of hardwood – and especially that of beech – in Swiss forests, as evidenced by the national forest inventories in 1982–1986 and 1993–1995, is confirmed for single regions and forest enterprises. The last two forest inventories show that hardwood produced a higher increment than softwood. The average volume of each standing tree also increased. Not only will it become possible to harvest more hardwood, but the opportunity is offered to process them into end products with a higher added value. But, in fact, the harvested hardwood volumes vary widely from year to year and between the regions of French-speaking Switzerland which were compared. This tends to prove that local market conditions and natural hazards, like the storms Vivian and Lothar,have a higher impact on the planning of forest. The volume of harvested hardwood will not increase as long as no extra financial incentives are given.

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