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1
Thapa, Ram. "Modeling Mortality of Loblolly Pine Plantations". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/46726.
Testo completoAbstract (sommario):
Accurate prediction of mortality is an important component of forest growth and yield prediction systems, yet mortality remains one of the least understood components of the system. Whole-stand and individual-tree mortality models were developed for loblolly pine plantations throughout its geographic range in the United States. The model for predicting stand mortality were developed using stand characteristics and biophysical variables. The models were constructed using two modeling approaches. In the first approach, mortality functions for directly predicting tree number reduction were developed using algebraic difference equation method. In the second approach, a two-step modeling strategy was used where a model predicting the probability of tree death occurring over a period was developed in the first step and a function that estimates the reduction in tree number was developed in the second step. Individual-tree mortality models were developed using multilevel logistic regression and survival analysis techniques. Multilevel data structure inherent in permanent sample plots data i.e. measurement occasions nested within trees (e.g., repeated measurements) and trees nested within plots, is often ignored in modeling tree mortality in forestry applications. Multilevel mixed-effects logistic regression takes into account the full hierarchical structure of the data. Multilevel mixed-effects models gave better predictions than the fixed effects model; however, the model fits and predictions were further improved by taking into account the full hierarchical structure of the data. Semiparametric proportional hazards regression was also used to develop model for individual-tree mortality. Shared frailty model, mixed model extension of Cox proportional hazards model, was used to account for unobserved heterogeneity not explained by the observed covariates in the Cox model.Ph. D.
2
Avila, Olga. "Modeling growth dynamics of juvenile loblolly pine plantations /". This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-10022007-144523/.
Testo completo
3
Avila, Olga B. "Modeling growth dynamics of juvenile loblolly pine plantations". Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39476.
Testo completoAbstract (sommario):
Modeling growth dynamics of juvenile loblolly pine plantations can help to address important management decisions that have to be made in young stands. The present study addressed diameter and height prediction as well as crown development analysis as functions of independent variables such as site index, relative spacing and age for trees younger than ten years old. It was found that height prediction for trees one and two years old was a function of the products of the variables site index and age (or square root of age) and relative spacing and age (or square root of age). For trees three years old and older these were also the independent variables used to explain height prediction but in this case age (or square root of age) was another significant independent variable. In regard to diameter prediction it was observed that groundline diameter was a function of age for trees one and two years old; while this variable was also a function of site index and relative spacing for trees three, four and five years old. For trees older than five years old diameter at breast height was a function of age, site index and relative spacing. The analysis of crown development showed that for trees five years old and older variables like diameter at breast height, total height, age, site index and relative spacing were significant when crown ratio was the dependent variable. For trees younger than five years old, groundline diameter and the other same independent variables (i.e. total height, age, index and relative spacing) were again found significant when crown ratio was the dependent variable.Ph. D.
4
Ibell, Paula Therese. "Edaphic and Ecophysiological Responses to Early Establishment Weed Control and Fertilisation in F1 Hybrid Pine Plantations of Southeast Queensland". Thesis, Griffith University, 2014. http://hdl.handle.net/10072/367975.
Testo completoAbstract (sommario):
Post-planting silviculture in the exotic pine plantations of Southeast Queensland focuses on fertilisation and weed control at early plantation establishment. Early establishment silviculture in pine plantations aims to reduce the competition for light, nutrients and water in the short term, while maximising resource conversion for growth in the long term. However, silviculture can be applied in a systematic way without necessarily considering the limitations to maximum tree growth at each site. Accordingly, silvicultural treatments could be applied in a site specific manner to better reflect the limitations to tree growth at each site (e.g. nutrition and/or water), or for maximum effectiveness based on seasonal limitations (e.g. weed competition, water availability). This research aimed to investigate the effects of early establishment weed control and fertilisation practices on soil carbon (C) and nitrogen (N) cycling (as an indicator of soil fertility), tree nutrition (particularly N nutrition), growth and eco-physiological responses, in the F1 hybrid exotic pine plantations (Pinus elliottii Engelm var. elliottii x Pinus caribaea Morelet var. hondurensis (Sènècl.) W.H.G. Barett & Golfari.) in the subtropics of Southeast Queensland.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
5
McCurdy, Wyatt Conner. "Characterizing spatiotemporal variation in LAI of Virginia Pine Plantations". Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/96595.
Testo completoAbstract (sommario):
Loblolly pine is an important managed tree species within the southeastern United States, and better understanding spatial patterns in its productivity has potential to contribute to both modeling and management of the species. Using recently-created pine management maps specific to Virginia and empirical relationships predicting pine LAI from the Landsat satellite, we conducted a statewide analysis of temporal patterns in stand-level southern pine leaf area index (LAI) following clear-cut and planting. Here, using 28 years of Landsat time-series data for 13,140 stands that were clear-cut between 2014-2017, we examined 1) when LAI peaked over the rotation, and 2) how LAI in each stand compared to a recommended fertilization threshold of 3.5 LAI. We found that, on average, winter LAI reached a maximum of 2.02., which can be approximately doubled to give a summer LAI of 4.04, and within stand peak occurred between years 13 and 15. We also found that around 45.8% of stands achieved an LAI value higher than 3.5: a fertilization threshold recommended for managed stands in Virginia. The dataset produced by our analysis will bolster information required for modeling loblolly pines as a plant functional type in regional land simulations, and the finding that most stands are below the recommended LAI fertilization threshold will fuel further management-motivated research.Master of Science
Management of pines in the southeastern U.S. contributes to the region's economy and carbon sequestration potential. In this study, we used Virginia forest harvest maps to identify individual patches (stands) of pine forest which had each gone through a full harvest life cycle (rotation). With unique managed pine stands identified, we used satellite imagery to estimate growth of canopy leaf area over time within each stand, using a metric called leaf area index (LAI). We identified 13,140 separate stands, each with up to 28 years of available data. We took the first full-state census of areas of managed pines in Virginia, and their leaf area development. We acquired one LAI measurement from February of each year, for each stand in Virginia. Using February LAI for each of our stands, we found that an average stand in VA has a maximum winter LAI of 2.02 (meaning an approximate maximum summer LAI of 4.04), and that stands generally reached their peak LAI after around 14 years of growth. It is recommended, in VA, that a landowner fertilize their stand in the middle of a harvest rotation if summer peak LAI is under 3.5, at stand closure. We found that at ten years of stand age, 45.8% of stands were estimated to reach above this threshold. Since this study's dataset is the most comprehensive LAI dataset for managed pines in VA, it may be used to improve management outcomes as well as understand pine productivity for land surface modeling purposes.
6
Avila, Olga B. "Survival equations for loblolly pine trees in cutover, site- prepared plantations". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040658/.
Testo completo
7
Wallertz, Kristina. "Pine weevil feeding in Scots pine and Norway spruce regenerations /". Alnarp : Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200960.pdf.
Testo completo
8
Bacon, Catherine G. "Interspecific competition in young loblolly pine plantations on the Virginia Piedmont". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49979.
Testo completo
9
Burkhalter, John Curtis. "Arthropod Biodiversity in Response to the Restoration of Former Pine Plantations". UNF Digital Commons, 2010. http://digitalcommons.unf.edu/etd/368.
Testo completoAbstract (sommario):
The goal of ecological restoration is to return degraded or altered ecosystems to their pre-disturbed state with respect to ecosystem structure, function, and composition. In the current study the research objective was to reestablish high levels of biodiversity on two restored pine plantations as well as restore a native pine flatwoods ecosystem. Managed, even-aged pine flatwoods are now the most extensive ecosystem in North Florida, comprising approximately 70% of the forested landscape. Slash pine trees were thinned in the experimental plots to restore the natural slash pine density of native ecosystems. In addition to the thinning treatments, experimental plots have been clear-cut and all vegetation removed from the plots. Arthropods were sampled by employing pitfall traps, sticky traps and sweep netting. This study assesseed the success of the restoration techniques employed by looking at biodiversity with a fine-resolution, taxonomically narrow approach by identifying the arthropods down to the taxonomic level of family and determining the number of morphospecies. Species were also subdivided into functional groups based upon the ecosystem services that they provide and their trophic level. Analyses revealed that arthropod species and guild diversity was not significantly affected by treatments in both 2008 and 2009. The experimental treatments were able to recover to pre-disturbance levels after two years following restoration. This indicates that these arthropod communities are fairly resilient and are able to recover fairly quickly following perturbation. Interestingly, community similarity measures revealed that although the experimental treatments were no more diverse than control plots the community species composition was fairly dissimilar between treatments, with plots becoming more dissimilar from 2008 to 2009. More long term data should reveal if these plots are proceeding along different successional trajectories in terms of community species composition and also will allow us to gain more insight into the long term effect of the treatments on biodiversity.
10
Westfall, James A. "Simulation of Early Stand Development in Intensively Managed Loblolly Pine Plantations". Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29950.
Testo completoAbstract (sommario):
A system of equations was developed and incorporated into the PTAEDA2 loblolly pine stand simulator to provide growth projections from time of planting. Annual height growth is predicted using a two-parameter Weibull function, where distribution parameters are estimated from equations that utilize site index and age as predictor variables. Allometric equations are employed to estimate tree diameter and height-to-crown attributes. First year after planting mortality estimates are based on physiographic region and drainage class, with adjustments for bedding or discing site preparation treatments. Thereafter, a simple mortality function is used. The onset of competition is defined through a point density measure, which was conditioned to correspond with inflection points of basal area growth curves from observed data.
Early silvicultural treatment response functions were also developed. These equations modify growth for shearing and piling, discing, and bedding site preparation methods, fertilization with phosphorous, nitrogen, and/or potassium, and 1-year or 2-year herbaceous weed control treatments. Differential responses due to drainage class and physiographic region are included in the response functions where necessary. Equations that account for interactions between certain treatments are used to adjust response levels where treatments have similar effects site conditions.
Analyses of pre-competitive growth projections where no treatments are specified reveal that a small amount of over-prediction is present when compared with observed data. Predicted values in the post-competitive growth phase confirm that the addition of the pre-competitive growth system did not significantly affect the predictive behavior of the PTAEDA2 model. The simulated growth responses attributed to early silvicultural treatments are consistent with response levels reported in other studies.Ph. D.
11
Dyer, Michael E. "Dominance/Suppression Competitive Relationships in Loblolly Pine (Pinus taeda L.) Plantations". Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/29298.
Testo completoAbstract (sommario):
Data from three long-term field studies with loblolly pine (Pinus taeda L.) plantations were used to examine inequality (Gini coefficient) trends in diameter and the relationship between diameter relative growth rate (r) and initial size. Analysis with two spacing studies shows inequality increases with increasing density. For a given initial density, inequality initially decreases and then begins to increase as trees compete for resources. The slope of the linear relationship between r and relative size also increases with increasing density. The slope is initially negative and switches to positive as competition intensifies. The switch in the slope of the r/size relationship occurs when the crown projection area exceeds 1.05 or when the crown ratio falls below 0.75. These results are consistent with the resource pre-emptive or dominance/suppression theory of intra-specific competition. The r/size trends are not evident when calculations are based on class means as opposed to individual trees. The slope of the r/size relationship is a function of stand height, density, and to a lesser extent, site quality. Density reduction through mid-rotation thinning tends to decrease the slope coefficient. The r/size trends are used to develop a disaggregation model to distribute stand-level basal area growth over an initial tree list. This approach compares well with two other disaggregation models but tends to over predict growth on the largest trees.Ph. D.
12
Stuckey, Harold Troy. "Ecological Enhancement of Timber Growth: Applying Compost to Loblolly Pine Plantations". Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2265/.
Testo completoAbstract (sommario):
This study explored the application of compost onto a small loblolly pine tree forest in northeast Texas. Its purpose was to determine if the application of various amounts of compost would provide for accelerated rates of growth for the trees. Soil parameters were also monitored. A total of 270 trees were planted and studied in a northeast Texas forest ecosystem. Compost rates of 5, 25, and 50 tons per acre with either soil or compost backfill were utilized and compared to a control without compost. Nonparametric and parametric ANOVA and Chi-Square tests were utilized. The results indicated that greater application rates retained greater moisture and higher pH levels in the soil. Compost applications also yielded a greater survival rate as well as larger tree height and diameter when compared to the control. The 25 ton/acre application backfilled in native soil achieved the greatest average in height and diameter when compared to the averages for the control plot. Greater growth differences for the 25S application can be attributed to additional nutrients coupled with a stable pH consistent with native soil acidity.
13
Burton, Joanne. "Soil Nitrogen Dynamics Under Adjacent Native Forest and Hoop Pine Plantations". Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365851.
Testo completoAbstract (sommario):
Single-species plantation forests have become the dominant source of inputs for the Queensland forest industry. Almost a quarter (50,000 ha) of the Queensland plantation estate is accounted for by plantations of the nitrogen (N) demanding species, hoop pine (Araucaria cunninghamii). The majority of the hoop pine estate was originally native forest, and is currently moving into the second rotation phase. The future of plantations of this N demanding species is dependent on the long-term maintenance of soil N cycling and availability. Land-use change can impact soil N dynamics; however there is currently limited knowledge of how the land-use change from native forest (NF) to first rotation (1R) hoop pine plantation and subsequent second rotation (2R) hoop pine plantation, and the associated disturbance due to site preparation have influenced soil N transformations and availability. The objectives of this study were to examine the impact of land-use change from 1) NF to 1R hoop pine plantation, and 2) 1R hoop pine plantation to 2R hoop pine plantation on soil N dynamics. The impact of the current 2R residue management strategy was also examined. The study was conducted in adjacent NF, 1R hoop pine plantation, and 2R hoop pine plantation (5-year old) in Yarraman State Forest, south-east Queensland. A laboratory incubation using the 15N isotope dilution method was undertaken in order to examine the impact of land-use change and residue management on gross N transformations. Results showed that land-use change had a significant impact on soil N transformations. The conversion of the NF to the 1R hoop pine plantation significantly reduced the availability of NH4+-N and NO3- -N. It also decreased the rate of gross N mineralisation (measured under anaerobic conditions) and gross nitrification (measured under aerobic conditions). This result was related to lower soil, litter and root C:N ratios in the NF compared to the 1R hoop pine plantation, indicating a reduction in organic matter quality associated with the land-use change. The conversion of 1R to 2R hoop pine plantation resulted in an increase in the gross rate of ammonification. This was attributed to an increase in mineralisation of native organic N associated with changes in soil physical conditions and microclimate as a result of harvesting. Residue management was found to have no significant influence on the soil N transformations in the 2R plantation approximately five years after establishment. A second study focused on quantifying the impact of land use and residue management on soil soluble organic N (SON) pools using a variety of extraction methods, including water, hot water, 0.5 M K2SO4, 2 M KCl and hot KCl. Both land use and residue management were found to have a significant influence on the size of soil SON pools. The conversion of NF to 1R hoop pine plantation tended to result in a decrease in the amount of soil SON and the potential to produce SON. This reduction coincided with increased soil, litter and root C:N ratios, and may therefore be the result of a decline in organic matter quality and quantity. The conversion of 1R to 2R hoop pine plantation generally resulted in a reduction in the amount of SON. Residue management also had a significant influence on soil SON pools, which tended to be higher in windrows of harvest residues than in tree rows. The impact of land-use change on the size, activity, and composition of the soil microbial community was examined using fumigation-extraction, CO2 respiration, and community level physiological profiling (CLPP) techniques. Landuse change from NF to 1R hoop pine plantation resulted in a reduction in microbial biomass and activity, and a shift in soil microbial community composition. While the conversion from 1R to 2R hoop pine plantation appeared to have no significant influence on the size and activity of the soil microbial community, there were some indications of a difference in community composition. Soil microbial biomass and activity tended to increase as the quality and quantity of organic matter input increased. An 18-month field-based study was conducted using the in-situ incubation method to examine the impact of land-use change on seasonal N dynamics. The results of this study were consistent with results from the laboratory studies. In general, the rate of N transformations and size of soil mineral N pools and microbial biomass were lower in the 1R soil compared to the NF soil. The 1R soils tended to have lower total C and total N, and higher C:N ratios compared to the NF soil, indicating that lower rates of N transformation and N availability in the 1R soil may be a result of significant reductions in organic matter quality and quantity. While the difference in the rates of net N mineralisation and net nitrification among the plantation soils were statistically insignificant, over the 18-month sampling period more N was mineralised and nitrified in the 2R soil compared to the 1R soil. Residue management also influenced the total amount of N transformed over the sampling period, with more N tending to be mineralised and nitrified in soil under windrowed residues compared to soil under tree rows. Seasonal fluctuations in soil N dynamics tended to be controlled by temperature and soil moisture. From these results, it was concluded that land-use change and residue management had a significant impact on soil N dynamics. This was possibly associated with shifts in the quality and quantity of organic inputs, soil microbial properties and microclimate conditions. Results from this study indicate that land-use change and residue management may have implications for the long-term productivity of the soil resource. Future studies are required to improve the understanding of the chemical and biological mechanisms driving changes in soil N dynamics.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Faculty of Science, Environment, Engineering and Technology
Full Text
14
Smith, Michael C. "Diameter and height increment and mortality functions for loblolly pine trees in thinned and unthinned plantations". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-03242009-040942/.
Testo completo
15
Shoemaker, Douglas A. "Remote sensing and simulation to estimate forest productivity in southern pine plantations". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011384.
Testo completo
16
Malan, G., E. Meyer e MD Panagos. "Riparian-zone rehabilitation in pine plantations: Grassland woodland for plants and birds?" South African Journal of Wildlife Research, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000857.
Testo completoAbstract (sommario):
The study compared plant and avian diversity and species composition between four
habitats to review the potential implications of two distinct management practices on a
forestry estate, namely to rehabilitate riparian zones to grasslands or woodlands as the two
habitats that historically occurred on the property.The study habitats were Plantation (Pinus
trees in riparian zone), Bushland (recently harvested), Grassland (cleared of broadleaf
plants), and Woodland (control). At seven sampling sites per habitat, a vegetation assessment
was conducted, while birds were caught with mist nests. Plant species richness
increased from Plantation to Woodland, whereas most bird species and individuals were
found in Bushland. Plant and bird species composition differed significantly between
habitats. Bushland and Grassland birds were closely associated with exotic forbs. Grassland
attracted birds with diverse habitat and nesting-site associations, and Woodland birds
associated with woody plants. It is recommended that the majority of riparian zones be
managed as grasslands, although the exact affect of the biennial summer burning and
presence of exotic plants on birds needs to be investigated. To attract cavity-nesting birds to
the Estate, some suitable riparian zones should be rehabilitated to Woodland by planting
Ficus andAcacia trees, as these trees are the most abundant and frequently occurring in this
habitat. Rather than manage avian diversity per se, the African stonechat in Grassland and
lesser honeyguide in Woodland can be employed as indicators of the rehabilitation state of
the riparian zones.
17
Westfall, James A. "Growth Models and Mortality Functions for Unthinned and Thinned Loblolly Pine Plantations". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/37010.
Testo completoAbstract (sommario):
Effects of thinning, such as increased diameter growth and decreased mortality in the residual stand, have been recognized by foresters for many years. These effects are largely the result of increased tree vigor which is induced by a decreased level of competition. These relationships are reflected in many of the models that are central to PTAEDA2, a growth and yield simulator which was developed for use with loblolly pine (Pinus taeda) plantations established on cut-over, site prepared lands. Data from a long-term thinning study served as a basis for attempting to improve the predictive output of PTAEDA2. Assessment of differences in model parameter estimates between three levels of thinning intensity led to various approaches to reach this goal. Height increment and mortality models were found to need no additional refinement and were re-fit using all available data. Diameter increment and crown ratio model forms could not account for thinning effects in their present form and thinning response functions that could provide the proper behavioral response were added to these models.Models were evaluated individually and in combinations in a reduced growth simulator. This reduced simulator is a modified form of the growth subroutines in PTAEDA2 and is designed to utilize external data. Results of growth simulation runs show improvements in predictive ability for the crown ratio model fit to all data and for the re-fit height increment model/crown ratio model with thinning response variable combination. The diameter increment model with a thinning response variable significantly improved diameter prediction within the simulator, but predicted stand volumes were poor. The re-fit mortality function resulted in greater prediction error for mortality than the original PTAEDA2 mortality function.Master of Science
18
VanderSchaaf, Curtis Lee. "Modeling maximum size-density relationships of loblolly pine (Pinus taeda L.) plantations". Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29489.
Testo completoAbstract (sommario):
Self-thinning quantifies the reduction in tree numbers due to density-dependent mortality. Maximum size-density relationships (MSDRs) are a component of self-thinning that describe the maximum tree density per unit area obtainable for a given average tree size, often quadratic mean diameter (D). An MSDR species boundary line has been defined as a static upper limit of maximum tree density -- D relationships that applies to all stands of a certain species within a particular geographical area. MSDR dynamic thinning lines have been defined as the maximum tree density obtainable within an individual stand for a particular D which have been shown to vary relative to planting density. Results from this study show that differences in boundary levels of individual stands cause the MSDR species boundary line slope estimate to be sensitive to the range of planting densities within the model fitting dataset. Thus, a second MSDR species boundary line was defined whose slope is the average slope of all MSDR dynamic thinning lines. Mixed-models are presented as a statistical method to obtain an estimate of the population average MSDR dynamic thinning line slope.
A common problem when modeling self-thinning is to determine what observations are within generally accepted stages of stand development. Segmented regression is presented as a statistical and less subjective method to determine what observations are within various stages of stand development. Estimates of D and trees per acre (N) where MSDR dynamic thinning lines begin and end on the logarithmic scale were used as response variables and predicted as a function of planting density. Predictions of MSDR dynamic thinning line beginning and ending D and N are used in an alternative MSDR dynamic thinning line slope estimation method. These models show that the maximum value of Reineke's Stand Density Index (SDI) varies relative to planting density.
By relating planting density specific Zone of Imminent Competition Mortality boundaries to a MSDR species boundary line, self-thinning was found not to begin at a constant relative SDI. Thus, planting density specific Density Management Diagrams (DMD) showed that self-thinning began at 40 to 72% for planting densities of 605 and 2722 seedlings per acre, respectively.Ph. D.
19
Short, E. Austin. "Predicting height to live crown increment for thinned and unthinned loblolly pine plantations". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10242009-020225/.
Testo completo
20
McPherson, T. Scott. "Restoration of degraded soils under red pine plantations on the Oak Ridges Moraine". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0016/MQ53454.pdf.
Testo completo
21
Young, Michael Joseph. "Effects of paper mill sludge on tree growth and competition in young red pine plantations". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12052009-020055/.
Testo completo
22
Houghton, Damon. "Minimum tree height sample sizes necessary for accurately estimating merchantable plot volume in Loblolly pine plantations". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-05022009-040541/.
Testo completo
23
Liu, Jiping. "Modelling inter- and intra-specific competition effects in loblolly pine (Pinus taeda L.) plantations". Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39707.
Testo completoAbstract (sommario):
Accounting for competition effects is an essential step in building any stand growth simulator. However, accurate modelling of competition effects depends upon a clear understanding of quantitative relationships of various aspects of stand dynamics, including distributional parameters and spatial statistics. This study addressed four aspects of competition effects: 1) competition effects on distributional parameter dynamics of tree size variables; 2) inter-specific (loblolly pine vs. hardwood) and intra-specific competition effects on basal area growth, 3) dynamics of spatial statistical characteristics of DBH and total height, and their relevance to intertree competition, 4) and spatial properties of competition measures by available stand simulators for loblolly pine (Pinus taeda L.) plantations. Competition was found to affect the distribution parameters such as coefficient of variation, skewness, and the general shapes of distributions for diameter measurements, total height, crown width and crown height. Competition expedites size differentiation and thereby increases distribution variability for all variables except crown height. Intertree competition also drives skewness of these variables negative, although the distributions of crown heights tends to be more symmetric. Normality assumption generally holds for diameter measurement, but distributions of total height and crown width deviate from, and those of crown height approach, normality with intensified competition. A set of competition driven equations was developed for the distribution parameters and was validated. The differences of distribution parameters among the variables studied could be attributed to their biological meanings.Ph. D.
24
Walsh, Terese Ann Catherine. "Diameter/basal area increment equations for loblolly pine trees in cutover, site-prepared plantations". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/94489.
Testo completoAbstract (sommario):
The objective of this study was to develop diameter/basal area increment equations for loblolly pine trees in thinned and unthinned plantations on cutover, site-prepared areas. Results indicated that one set of coefficients was sufficient to estimate individual tree growth (for the three year period following thinning) on lightly thinned and heavily thinned plots. However, unthinned plots required a separate set of coefficients and therefore a separate equation to estimate growth.
Diameter growth was adequately explained by some form of the following regressor variables: pine basal area, hardwood basal area, initial age, initial diameter, average height of the dominant and codominant trees, and crown ratio ( optional). Transforming the dependent variable from a function of diameter to a similar function of basal area had no apparent effect on the precision of the predicted results.
Two alternative methods of predicting diameter growth were evaluated: (1) direct fitting of diameter growth, and (2) fitting a potential diameter growth equation and a modifier function. Even though the potential times modifier approach performed slightly better in terms of fitting the data, it provided unrealistic results at ages beyond the upper range of the data. After additional data are obtained at older ages, the potential times modifier approach may surpass the direct approach. However, at present, the direct diameter growth model was chosen as the final model form.M.S.
25
Paganelli, David. "Nitrogen dynamics after site preparation in three loblolly pine plantations on the Virginia Piedmont". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91052.
Testo completoAbstract (sommario):
Intensive site preparation practices and their effect on nitrogen cycling have been implicated as possible causes of productivity declines on forest sites in Australia and New Zealand. This study was initiated in order to determine the effects of site preparation intensity upon N distribution and availability in loblolly pine (Pinus taeda L.) plantations in Virginia. In the summer of 1982, three forest sites at the Reynolds Homestead Research Center on the Virginia Piedmont were clearcut. In the fall of the same year all three sites were prepared for planting using one of the following treatments: 1. shear, rake, disk (S,R,D) (3-passes); 2. shear-disk (S-D) (1-pass); and 3. chop, burn (C,B) (high intensity burn). During March of 1983, 1-0 genetically improved loblolly pine seedlings were planted on all sites. Pine biomass was greatest on the S,R,D area after three growing seasons. Total biomass and N content (NCONT) of native vegetation and forest floor were greatest in the S-D area. Total N in the upper 15 cm of mineral soil was also greatest in the S-D area. Total system N was highest in the S-D area and this treatment is more N-conservative than either of the more intensive treatments. During the third growing season potentially mineralizable N levels were highest on the two disked treatment areas, 157 and 144 kg N/ha for the s-o, and S,R,D areas, respectively. Pine foliar nutrient concentrations determined after the second and third growing seasons provided no evidence of existing or impending nutrient deficiencies. These results show that short-term pine nutrition and growth were not adversely affected by reductions of N capital on these sites. However, if wasteful practices, such as raking and burning with high intensity fires, are also used to establish subsequent stands on these same sites, cumulative losses of N could result in productivity declines.M.S.
26
Levitan, Jason. "Die-off of pathogens and assessment of risks following biosolids application in pine plantations". Thesis, Levitan, Jason (2010) Die-off of pathogens and assessment of risks following biosolids application in pine plantations. PhD thesis, Murdoch University, 2010. https://researchrepository.murdoch.edu.au/id/eprint/5101/.
Testo completoAbstract (sommario):
In Western Australia over 80,000 tonnes per annum of biosolids are produced from the treatment of wastewater. The biosolids is being disposed in a variety of land-application processes as a soil amendment. However the presence of pathogenic organisms in the biosolids can result in a human health risk if individuals are exposed to the biosolids.
Application of these biosolids to pine plantations is a practice increasing worldwide due to the benefits of biosolids as a soil amendment. The regulations allow biosolids that may contain pathogenic organisms to be landapplied. In the case of pine plantations, the general public is not physically excluded from the area resulting in a situation arising whereby exposure of the biosolids to members of the general public can occur. This potential exposure results in a human health risk becoming present.
Instances of pathogen survival post-application of biosolids have been observed indicating that the risk to human health is certainly present. The main aim of this study was to assess the risk to human health from the pathogens found in biosolids land applied to the Myalup pine plantation in Western Australia. To achieve this aim the ability of the pathogens to survive post-application of biosolids was monitored and any instances of increased pathogen activity beyond one year post-application were established. The airborne pathogen risks through the formation of biosolids dust and the occurrence of plantation burns that may cause pathogens to become airborne in the smoke of a burn, were investigated. E. coli, Salmonella spp. and Clostridium perfringens were the pathogen indicators selected for this study.
The results show that the pathogen levels in the land-applied biosolids pose a risk to members of the public and plantation workers via direct exposure for the first 3 months post-application. After 2 months E. coli was observed to have undergone significant die-off, Salmonella spp. was observed to be at undetectable levels after 3 months. However 11 months post-application in the following winter season, Salmonella spp. returned to high levels that would pose a human health risk. Clostridium perfringens remained at high levels throughout the 1 year monitoring period. During this initial monitoring period, a relationship between moisture content and pathogen populations was observed. Salmonella spp. indicated the strongest relationship with a return in its population from undetectable levels to high levels when an increase in moisture content was observed.
A mechanism that facilitates this increase in the populations of the pathogens has been referred to in the literature, but not described. An observation during the initial one-year intensive monitoring showed that as the moisture content of the biosolids reduced, the biosolids dried to form clumps. After testing, it was determined that these clumps were enabling weakened populations of the pathogens to survive the natural environmental factors that usually cause their die-off. After a rainfall event, the moisture content of the clumps increases allowing the weakened populations to re-colonise the biosolids. This clumping phenomenon was only observed to occur within the first year post-application. Beyond one year post-application, instances of elevated pathogen activity were observed up to 1.5 years post-application. After this period of time had elapsed, all indicator pathogens were observed to be at low levels that are highly unlikely to cause a human health risk. The indication being that no health risk from biosolids pathogens exists beyond 1.5 years post-application.
An alternative exposure route identified is the airborne route through inhalation of the pathogens. Plantation burns are expected to occur within the life-cycle of a plantation. The possibility that pathogens could become airborne during a burn and be transported along with the smoke was investigated. No significant instances of pathogens being transported in the smoke were observed.
The formation of biosolids dust was an issue raised, and more specifically whether pathogens could become airborne with the dust. The ability of the pathogens to survive in biosolids dust was examined. The pathogens indigenous to the biosolids failed to survive to the point where moisture loss in the biosolids was significant enough to allow dust formation to occur. Laboratory cultures of the indicator pathogens were then inoculated into the samples and their ability to survive in biosolids dust conditions was observed. Significant die-off was observed within 3 days and after 10 days the pathogen levels were low. Clostridium perfringens was the exception as this pathogen was observed to survive within biosolids dust.
The combined results of this thesis and the literature indicate that the human health risks relating to airborne exposure are limited to an occupational risk only. The pathogen risks are only associated with the application of the biosolids to the land and not with the formation of biosolids dust or with the smoke of plantation burn over land applied with biosolids.
The pathogen risk from direct exposure is present for all individuals who come into contact with the biosolids during the initial 3 months post-application and, due to pathogen re-growth or re-colonisation, the following winter season when moisture levels are increased. However this direct exposure risk is only present for 1.5 years-post-application after which the pathogens were observed to be of no health risk. In general the human health risk from the land-application of biosolids is low.
Additional research work needs to be conducted in relation to the clumping phenomenon. A full understanding of the process and why the biosolids forms clumps as it dries will aid in the development of strategies to prevent this action from occurring. Removing this action will greatly reduce the risk of pathogen regrowth and/or re-colonisation.
27
Tutua, Shane Sarere. "Residue Management and Carbon and Nutrient Cycling in Exotic Pine Plantations of Southeast Queensland". Thesis, Griffith University, 2009. http://hdl.handle.net/10072/366298.
Testo completoAbstract (sommario):
In Southeast Queensland, Australia, future wood production from exotic pines will rely heavily on second-rotation plantations. This increases the importance of sustaining soil fertility through logging or harvest residue retention for soil organic matter (SOM) maintenance in forest plantations. However, a greater understanding of harvest residues and their impact is essential to fully realise the potential of harvest residue management as an integral component of sustainable production forestry. Therefore, this study examined the nature of harvest residues, their decomposition and nutrient release dynamics, and the short- and long-term impacts of the residues on soil carbon (C), nitrogen (N) and phosphorous (P) pools, tree nutrition, growth and productivity in exotic pine plantations of Toolara State forest (26 degrees 00' South, 152 degrees 49' East), Maryborough districy, southeast Queensland.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
28
Hanberry, Brice Bond. "Birds and small mammals, intensively established pine plantations, and landscape metrics of the Coastal Plain". Diss., Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-09242007-101423.
Testo completo
29
Jones, Phillip Daniel. "Effects of five different intensities of stand establishment on wildlife habitat quality and tree growth in loblolly pine (Pinus taeda) plantations in southern Mississippi". Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-03192008-095948.
Testo completo
30
Blackwell, Bruce Alan. "Some ecological effects of operations used to convert densely stocked lodgepole pine stands into young pine plantations in west central British Columbia". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27395.
Testo completoAbstract (sommario):
Large areas of the interior of B.C. are covered with densely stocked lodgepole pine {Pinus contorta) forests, 40-60 years old. These forests are growing very slowly and some are not considered to be capable of contributing to future timber supplies. When stands have densities around 20,000 stems/ha or greater they are unlikely to produce merchantable trees within a reasonable period of time without treatment. To bring the more repressed stands back into timber production it is necessary to clear them and regenerate new ones with a more desirable stocking level (rehabilitation).
A study of the ecological effects of rehabilitation treatments on such stands in the Sub-Boreal Spruce Zone in the Lakes Forest District, west central B.C. was begun in July, 1985. This study quantified the effects of treatments on fuels, ecosystem nutrient status, associated vegetation, mineral soil and planted lodgepole pine seedlings to help assess the most economically and ecologically desirable method of treatment.
The study investigated the effects of two treatments - mechanical knocking down of trees followed by broadcast slashburning and mechanical knocking down followed by windrowing then burning - and 4 sets of burning conditions designed to give 4 different types of burning severities based on fuel consumption. Each treatment/burning severity was replicated 2-3 times on plots approximately 1 ha in size. The knocking down commenced in late 1985 and 3 of 4 sets of burns were carried out during spring and summer 1986. The remaining set of burns was carried out during spring, 1987.
It was found that over the range of burning conditions used, windrow burns consumed similar amounts of slash fuels, unlike broadcast burns which consumed greater amounts of slash fuel as the fuel moisture codes of the Canadian FWI system increased. Forest floor consumption was generally only a small proportion of the total fuel consumption.
Total nutrient losses decreased in the order N > S > P > Mg > Ca > K > Na. For the windrow burns, generally > 90% of all nutrients present in organic matter were lost during the burning. Nutrient quantities lost from windrow burns were significantly greater than quantities lost from broadcast burns. Windrow burn nutrient losses were generally greater than those lost from operational broadcast slashburns and were more similar to reported losses from whole tree harvesting operations. Some increases and some decreases in nutrient quantities were observed in the surface mineral soil in both the treatments.
The greatest changes in soil nutrients were generally observed for Ca and N. Fire severity significantly influenced the loss of both total and mineralizable N, while both site preparation treatment and fire severity influenced the loss of S. Relatively large increases in mineral soil nutrient quantities were observed beneath windrows. The mineral soil inter-windrow areas, however were found not to be greatly affected by the treatment. The large increases beneath windrows were attributed to the burning of large fuel accumulations.
Lodgepole pine seedling survival after two years was highest on areas between windrows and lowest on areas beneath windrows. The better survival in areas between windrows was attributed to improved soil temperature, while poorer survival in windrows was attributed to moisture stress caused by the creation of a hydrophobic layer or seedlings being planted in ash rather than mineral soil. Total height, height increment and basal diameter of lodgepole pine seedlings were greater on areas between windrows and least on broadcast burned areas. Biomass of understory vegetation during the first two post-treatment growing seasons decreased in the order: herbs > shrubs > mosses. Neither site preparation treatment nor fire severity appeared to have a significant effect on herb, shrub, or moss biomass during the first two post-treatment growing seasons. For individual species, biomass decreased in the order: Epilobium > Cornus > Spirea > Rosa > Linnaea.Forestry, Faculty of
Graduate
31
Zhang, Li, e n/a. "Bacterial Diversity of Australian Exotic Pine Forest Soil and Leaf Litter". Griffith University. School of Biomolecular and Biomedical Science, 2007. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20071128.094745.
Testo completoAbstract (sommario):
Forest plantations, widely grown for wood production, involve the selective promotion of single tree species, or replacement of natural species by exotic tree species. Slash pine (Pinus elliottii) has been chosen for reforestation of infertile sandy soils in southeast Queensland, Australia. These exotic pine plantations minimise soil and water losses, and are important scientific study sites. The soil environment of these plantations, though devoid of sufficient nutrients, oxygen and other factors, harbours innumerable bacteria that may play a crucial role in maintaining soil quality and ecosystem functions. These soil microorganisms also have the potential for use as sensitive biological indicators to reflect environmental changes. It is therefore essential to understand the interrelationships amongst bacterial communities and their environment by assessing their structural and functional diversity, and their responses to disturbances. The microbial community of an exotic pine plantation of subtropical Australia was analysed by both culture-dependent and culture-independent methods. In this study, a leaf litter-soil core sample (25 cm x 40 cm) was collected from a 22-year-old slash pine plantation in southeast Queensland, Australia in October, 2003. The core sample was divided into three fractions, namely, L layer leaf litter, F layer leaf litter, and forest soil 0-10 cm. In the culture-independent study, a modified DNA extraction and purification method was used to obtain highly purified high-molecular-weight DNA. This DNA was successfully used to amplify bacterial 16S rRNA genes with universal primers Fd1 and R6, to produce products of approximately 1500 bp. PCRamplified 16S rRNA genes were subsequently cloned and a total of 194 clones from leaf litter and soil were partially sequenced (about 510 bp). The 16S rRNA gene sequences were analysed and grouped into several phylogroups (the sequences with a similarity value ¡Ý 98 % were regarded as phylogenetically similar and grouped into one phylogroup). Sequencing representatives (¡Ö 1400 nucleotides) from each phylogenetic group confirmed that five bacterial phyla were represented in the forest soil clone library. Phylum Acidobacterium was the most abundant phylogenetic group in terms of the number of clones and accounted for 42 % of all examined soil clones. The Verrucomicrobiales and Proteobacteria were the second and third most abundant phylogenetic groups found in the soil clone libraries, accounting for 12 % and 11 % of the soil clones, respectively. About 8 % of all examined soil clones were Planctomycetes and 27 % of soil clones were phylogenetically unidentified. The large amount of unclassified clone sequences could imply that novel groups of bacteria were present in the forest soil. When the two fractions of leaf litter clone libraries were compared, Firmicutes was the only phylum represented in the L layer leaf litter clone library. Similarly, Firmicutes dominated the F layer leaf litter (79 % of the library), was followed by Proteobacteria (21 %). For the culture-dependent study, a total of 21 isolates which were considered to represent 334 colonies from the leaf litter and forest soil were identified by 16S rRNA gene sequence analysis, indicating that L layer leaf litter and F layer leaf litter were dominated by Firmicutes (48 %) and Proteobacteria (69 %) respectively, and 91 % of the isolates from the forest soil were Firmicutes. Using culture-independent methods, Actinobacteria appeared to be absent from the L and F layer leaf litter and forest soil samples. The results implied that either the nucleic acids of Actinobacteria were difficult to extract or Actinobacteria were over represented in the culture-dependent examinations. Phylum Acidobacteria appeared to be numerically dominant and active members in most soils. However, only one named species had been isolated from an acid mine drainage site and reported by Kishimoto and Tano (1987). Analysis by culture-dependent methods revealed a different bacterial diversity, compared to the bacterial diversity from the 16S rRNA gene clone sequences. The most significant result was the observation that, as revealed by both culture-dependent and culture-independent methods, the bacterial diversity presented in the leaf litter was greatly different from the community of the soil. During the culture-dependent bacterial diversity study, four novel strains were isolated from the forest soil and leaf litter samples and complete characterisations of these novel strains were carried out. Reports on the descriptions of Bacillus decisifrondis strain E5HC-32T from forest soil and Frondicola australicus strain E1HC-02T from L layer leaf litter have been published (appendix). The information provided by assessing the microbial communities in different fractions of leaf litter and forest soil improves our understanding of the phylogenetic relationship between soil and leaf litter. It is suggested, in this study, to perform both culture-dependent and culture-independent methods to characterise the bacterial structure and diversity in forest litter and soil samples, particularly in response to different forest management practices and global change. This study also provides the basis for further functional studies of the forest soil and leaf litter of exotic pine plantation in subtropical Australia.
32
Björklund, Niklas. "Movement behaviour and resource tracking in the pine weevil Hylobius abietis /". Uppsala : Dept. of Entomology, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s302.pdf.
Testo completo
33
Zhang, Li. "Bacterial Diversity of Australian Exotic Pine Forest Soil and Leaf Litter". Thesis, Griffith University, 2007. http://hdl.handle.net/10072/366994.
Testo completoAbstract (sommario):
Forest plantations, widely grown for wood production, involve the selective promotion of single tree species, or replacement of natural species by exotic tree species. Slash pine (Pinus elliottii) has been chosen for reforestation of infertile sandy soils in southeast Queensland, Australia. These exotic pine plantations minimise soil and water losses, and are important scientific study sites. The soil environment of these plantations, though devoid of sufficient nutrients, oxygen and other factors, harbours innumerable bacteria that may play a crucial role in maintaining soil quality and ecosystem functions. These soil microorganisms also have the potential for use as sensitive biological indicators to reflect environmental changes. It is therefore essential to understand the interrelationships amongst bacterial communities and their environment by assessing their structural and functional diversity, and their responses to disturbances. The microbial community of an exotic pine plantation of subtropical Australia was analysed by both culture-dependent and culture-independent methods. In this study, a leaf litter-soil core sample (25 cm x 40 cm) was collected from a 22-year-old slash pine plantation in southeast Queensland, Australia in October, 2003. The core sample was divided into three fractions, namely, L layer leaf litter, F layer leaf litter, and forest soil 0-10 cm. In the culture-independent study, a modified DNA extraction and purification method was used to obtain highly purified high-molecular-weight DNA. This DNA was successfully used to amplify bacterial 16S rRNA genes with universal primers Fd1 and R6, to produce products of approximately 1500 bp. PCRamplified 16S rRNA genes were subsequently cloned and a total of 194 clones from leaf litter and soil were partially sequenced (about 510 bp). The 16S rRNA gene sequences were analysed and grouped into several phylogroups (the sequences with a similarity value ¡Ã 98 % were regarded as phylogenetically similar and grouped into one phylogroup). Sequencing representatives (¡Ã– 1400 nucleotides) from each phylogenetic group confirmed that five bacterial phyla were represented in the forest soil clone library. Phylum Acidobacterium was the most abundant phylogenetic group in terms of the number of clones and accounted for 42 % of all examined soil clones. The Verrucomicrobiales and Proteobacteria were the second and third most abundant phylogenetic groups found in the soil clone libraries, accounting for 12 % and 11 % of the soil clones, respectively. About 8 % of all examined soil clones were Planctomycetes and 27 % of soil clones were phylogenetically unidentified. The large amount of unclassified clone sequences could imply that novel groups of bacteria were present in the forest soil. When the two fractions of leaf litter clone libraries were compared, Firmicutes was the only phylum represented in the L layer leaf litter clone library. Similarly, Firmicutes dominated the F layer leaf litter (79 % of the library), was followed by Proteobacteria (21 %). For the culture-dependent study, a total of 21 isolates which were considered to represent 334 colonies from the leaf litter and forest soil were identified by 16S rRNA gene sequence analysis, indicating that L layer leaf litter and F layer leaf litter were dominated by Firmicutes (48 %) and Proteobacteria (69 %) respectively, and 91 % of the isolates from the forest soil were Firmicutes. Using culture-independent methods, Actinobacteria appeared to be absent from the L and F layer leaf litter and forest soil samples. The results implied that either the nucleic acids of Actinobacteria were difficult to extract or Actinobacteria were over represented in the culture-dependent examinations. Phylum Acidobacteria appeared to be numerically dominant and active members in most soils. However, only one named species had been isolated from an acid mine drainage site and reported by Kishimoto and Tano (1987). Analysis by culture-dependent methods revealed a different bacterial diversity, compared to the bacterial diversity from the 16S rRNA gene clone sequences. The most significant result was the observation that, as revealed by both culture-dependent and culture-independent methods, the bacterial diversity presented in the leaf litter was greatly different from the community of the soil. During the culture-dependent bacterial diversity study, four novel strains were isolated from the forest soil and leaf litter samples and complete characterisations of these novel strains were carried out. Reports on the descriptions of Bacillus decisifrondis strain E5HC-32T from forest soil and Frondicola australicus strain E1HC-02T from L layer leaf litter have been published (appendix). The information provided by assessing the microbial communities in different fractions of leaf litter and forest soil improves our understanding of the phylogenetic relationship between soil and leaf litter. It is suggested, in this study, to perform both culture-dependent and culture-independent methods to characterise the bacterial structure and diversity in forest litter and soil samples, particularly in response to different forest management practices and global change. This study also provides the basis for further functional studies of the forest soil and leaf litter of exotic pine plantation in subtropical Australia.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Biomedical Sciences
Faculty of Science and Technology
Full Text
34
Highet, Anne Elizabeth. "Visual impact of wildfire in pine plantations : an inventory of impact and recommendations for rehabilitation /". Title page, contents and abstract only, 1985. http://web4.library.adelaide.edu.au/theses/09AR/09arh638.pdf.
Testo completo
35
Arthaud, Greg John. "Economic comparisons of thinning from above and below in Loblolly Pine plantations using dynamic programming". Thesis, Virginia Tech, 1986. http://hdl.handle.net/10919/45663.
Testo completoAbstract (sommario):
Thinning from above and below were compared using an economic optimizing dynamic program, FORTE (Arthaud 1986). Economically optimal (net present value maximizing) thinning regime and rotation age were determined for benchmark economic and model inputs. Sensitivity of net present value and optimal management regime were tested for varying interest rates (6 or 8%), site indexes (50, 60 and 70, base 25 years), fixed and variable thinning costs, planting density (440, 680 and 910 trees per acre), stumpage prices and thinning type. Given the same assumptions, thinning from below consistantly provided the higher net present value for the optimal regime than thinning from above. For the benchmark assumptions, both thinning types had two thinnings in their optimal regimes. Optimal rotation age and thinning timings occur later when thinning from above. Both thinning types provided higher net present values than not thinning under all conditions except pulpwood management.
Master of Science
36
Tacilla, Villanueva Antonio. "Impacts of Fertilization on Soil Properties in Loblolly Pine Plantations in the Southeastern United States". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54020.
Testo completoAbstract (sommario):
We examined the effects of periodic nitrogen (N) and phosphorus (P) fertilizer applications on the O horizon and mineral soil in loblolly pine (Pinus taeda L.) plantations over a 12-year period. To accomplish this, we used 9 experimental sites located across the south, which were grouped using the CRIFF Classification System. Group 1—CRIFF A, B (poorly-drained Ultisols); group 2—CRIFF C, D, G (sandy Spodosols and Entisols); and group 3—CRIFF E, F (well-drained Ultisols). Fertilization rates were 135, 202, and 269 kg N ha-1 at 4 years application frequency. This resulted in a cumulative N application rate of 540, 808, and 1076 kg ha-1. P was added at 10% of the N rate. Fertilization increased the mass, N content, and P content of the O horizon in all soil groups. Fertilization did not impact mineral soil N. No significant increases in total N trends were observed to a depth of 1 m. Likewise, total inorganic N (NH4+ + NO3-) was not affected by fertilization. These results suggest that N fertilization will have little effect on long-term soil N availability regardless of soil types. In contrast, fertilization increased extractable P in soil CRIFF groups 1, 2, and 3 by 26, 60, and 4 kg P ha-1 respectively suggesting potential for long-term soil P availability and site quality improvement. However, the low extractable P in soil group 3 implies additional fertilization with P for the next rotation for sites included into this soil group.Master of Science
37
Rune, Göran. "Instability in plantations of container-grown Scots pine and consequences on stem form and wood properties /". Uppsala : Dept. of Forest Products and Markets, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s281-ab.html.
Testo completo
38
Mason, Euan G. "Decision-support systems for establishing radiata pine plantations in the central North Island of New Zealand". Thesis, University of Canterbury. Forestry, 1992. http://hdl.handle.net/10092/7205.
Testo completoAbstract (sommario):
A framework for decision-making relating to establishment of radiata pine plantations was defined, with provision for both numerical models and non-numerical representations of knowledge.
Data from Nelder-design experiments were used to investigate the amount of between-tree competition occurring in young radiata pine plantations. Dbhob was found to be unrelated to initial stocking prior to year five. Modelling of basal area/ha growth and yield in a Nelder-design experiment showed that functions used in traditional basal area models under-estimated basal area growth during the two years following the time when mean height was 1.40 m. An adjustment was made to these functions, allowing for allometric assumptions on which growth models are based, which improved models estimates of early basal area/ha growth.
Models of young radiata pine survival and size class distribution models were built for crops aged 0 to 5 years in the Central North island region of New Zealand. Data came from site preparation experiments, and the models are sensitive to variations in altitude and site preparation practices. Off-site preparation practices studied, weed control was found to have the largest effect on both initial survival and growth. Mounding improved growth to a lesser extent, and cultivation improved survival of young trees. Fertilisation with nitrogen and phosphorous was found to have a negligible effect on growth and no effect on tree survival.
The basal area/ha function incorporated the allometric adjustment developed during the analysis of Nelder-design experiments in a way which resulted in compatible mean height and basal area/ha models.
As an illustration of the potential for non-numerical decision-support tools, a knowledge-based computer program was developed to assist forest managers in selecting herbicidal treatments prior to, or during the years following plantation establishment. The system was built using techniques developed for artificial intelligence applications, in a form which allows updating of knowledge relating to weeds, herbicides, surfactants, application methods and treatments, by experts unfamiliar with computer programming.
Opportunities for incorporation of these tools into a comprehensive decision-making and control system are discussed.
39
Dyer, Alexei. "Blattodea as potential indicators of Peninsula Granite Fynbos restoration following the clear-felling of pine plantations". Bachelor's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/7628.
Testo completoAbstract (sommario):
Alien plant invasions pose a major threat to the biodiversity of the Cape Peninsula; currently facilitating the transformation of native vegetation and alien invertebrate invasions. This threat provided a motive for the removal of alien pine plantations from the lower slopes of Table Mountain, with the aim of restoring the currently endangered Peninsula Granite Fynbos vegetation. Despite some indication that native fynbos vegetation is recovering, the recovery of native invertebrate communities and their associated ecosystem function remains uncertain. Epigaeic invertebrates are easily sampled, highly abundant, responding rapidly to changes in habitat condition. This study investigates the potential of Blattodea species to be employed as ecological indicators of Peninsula Granite Fynbos restoration, along a chronosequence of recently-felled pine stands. Within 10 years of clear-felling, Blattodea communities inhabiting recovering fynbos do not appear to be very distinct in terms of species richness or composition from those inhabiting undisturbed Peninsula Granite Fynbos, indicating restoration progress. Despite the presence of endemic species among both habitat types, the abundance of the invasive Portuguese millipede (Ommatoiulus moreletii) at clear-felled sites suggests that the ecological footprint of pine still persists. The influence of pine could be reduced by implementing the follow-up clearance of alien trees and pine debris. Although an ecological indicator species was identified, its robustness needs to be tested under a range of spatial and temporal conditions.
40
McElligott, Kristin Mae. "Soil Respiration and Decomposition Dynamics of Loblolly Pine (Pinus taeda L.) Plantations in the Virginia Piedmont". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/75154.
Testo completoAbstract (sommario):
Forests of the southeastern U.S. play an important role in meeting the increasing demand for forest products, and represent an important carbon (C) sink that can be managed as a potential tool for mitigating atmospheric CO2 concentrations and global climate change. However, realizing this potential depends on full accounting of the ecosystem carbon (C) budget. The separate evaluation of root-derived, autotrophic (RA) and microbially-derived heterotrophic (RH) soil respiration in response to management and climate change is important, as environmental and ecological factors often differentially affect these components, and RH can be weighed against net primary productivity (NPP) to estimate the C sink or source status of forest ecosystems. The objective of this research was to improve the quantitative and mechanistic understanding of soil respiratory fluxes in managed loblolly pine (Pinus taeda L.) plantations of the southeastern U.S. To achieve this overall objective, three studies were implemented to: 1) estimate the proportion and seasonality of RH:RS in four stand age classes, and identify relationships between RH:RS and stand characteristics 2) evaluate the effects of forest nutrient management and throughfall reduction on factors that influence RH and decomposition dynamics, including litter quality, microbial biomass, and enzyme activity and 3) evaluate the sensitivity of sources of RH (mineral soil-derived heterotrophic respiration; RHM, and leaf litter-derived heterotrophic respiration; RHL) to varying soil and litter water content over the course of a dry down event, and assess whether fertilization influences RH. Stand age and measurement season each had a significant effect on RH:RS (P < 0.001), but there were no interactive effects (P = 0.202). Mean RH:RS during the 12-month study declined with stand age, and were 0.82, 0.73, 0.59, and 0.50 for 3-year-old, 9-year-old, 18- year-old, and 25-year-old stands, respectively. Across all age classes, the winter season had the highest mean RH:RS of 0.85 while summer had the lowest of 0.55. Additionally, there were highly significant (P < 0.001) and strong (r > 0.5) correlations between RH:RS and peak LAI, stem volume, and understory biomass. Fertilization improved litter quality by significantly decreasing lignin:N and lignin:P ratios, caused a shift in extracellular enzyme activity from mineral soil N- and P-acquiring enzyme activity to litter C-acquiring enzyme activity, and increased microbial biomass pools. Throughfall reduction decreased litter quality by increasing lignin:N and lignin:P, but also increased C-acquiring enzyme activity. RHL was more sensitive to water content than RHM, and increased linearly with increasing litter water content (R2 = 0.89). The contribution of RHL to RH was greatest immediately following the wetting event, and decreased rapidly to near-zero between three – 10 days. RHM also had a strong relationship with soil water content (R2 = 0.62), but took between 200 – 233 days to attain near-zero RHM rates. Fertilization had no effect on RHM (P = 0.657), but significantly suppressed RHL rates after the wetting event (P < 0.009). This research provides estimates of RH:RS in managed loblolly pine systems that can be used to improve regional ecosystem C modeling efforts, and demonstrates the need to consider the impact of stand age and seasonal patterns to identify the point at which plantations switch from functioning as C sources to C sinks. Additionally, it demonstrates that the controls over RH are dynamic and influenced in the short-term by fertilization and changed precipitation regimes, with the greatest impact on properties affecting litter RH compared to mineral soil. Future research should work to improve the mechanistic understanding of the seasonal and spatial variability of RH and related controlling biotic and abiotic parameters to remedy the variability in existing RS and ecosystem C models. Understanding how management and climate change may impact factors that control RH will ultimately improve our understanding of what drives changes in forest C fluxes.Ph. D.
41
Watson, Lisa E. "Relationships between loblolly pine (Pinus taeda L.) yield and woody plant diversity in Virginia Piedmont plantations". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08292008-063155/.
Testo completo
42
Wallertz, Kristina. "Pine weevil Hylobius abietis feeding in shelterwood systems /". Alnarp : Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/10040784.pdf.
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Neal, Andrew Wilson. "Soil Carbon and Nitrogen Dynamics Across the Hillslope-Riparian Interface in Adjacent Watersheds with Contrasting Cellulosic Biofuel Systems". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48125.
Testo completoAbstract (sommario):
Climate change resulting from emissions of fossil fuel combustion has sparked considerable interest in renewable energy and fuel production research, particularly energy derived from cellulosic ethanol, which is derived from biomass such as wood and grass. Cellulosic ethanol demonstrates a more promising future as a global energy source than corn-derived ethanol because it does not displace food crops, irrigation is not required, and chemical application rates are much lower than for annual crops, such as corn. Growing cellulosic biomass for energy can help reduce greenhouse gas emissions via carbon (C) sequestration and by reducing demand for fossil fuel production. The objective of this study was to investigate how land use change affects soil properties and selected soil C and nitrogen (N) dynamics among alternative cellulosic biofuel treatments at the Weyerhaeuser Alabama Cellulosic Biofuel Research site in west-central Alabama. Composite soils for characterization, along with forest floor, were collected at year 1 and year 2 after treatment establishment at 0-15cm and 15-30cm depths at six locations along three hillslope-riparian transects in five experimental watershed treatments. Decomposition of loblolly pine needles was assessed in each watershed using an in situ litter bag method. Seasonal in situ net nitrogen mineralization was measured using a sequential core method, and an anaerobic incubation for N mineralization potential of composite soils was performed in the laboratory. Results revealed high variability of soil properties and processes within these watersheds, along with no consistent treatment effects. This study provides baseline data for these watershed treatments for future studies.Master of Science
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Компанець, Р. А. "Проект організації плантаційного насадження кедрових сосен в ДПТНЗ «Сновське вище професійне училище лісового господарства»_". Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25064.
Testo completoAbstract (sommario):
Компанець, Р. А. Проект організації плантаційного насадження кедрових сосен в ДПТНЗ «Сновське вище професійне училище лісового господарства» : випускна кваліфікаційна робота : 205 "Лісове господарство" / Р. А. Компанець ; керівник роботи Л. А. Шевченко ; НУ "Чернігівська політехніка", кафедра аграрних технологій та лісового господарства. – Чернігів, 2021. – 70 с.Кваліфікаційна робота Компанець Р.А. «Проект організації плантаційного насадження кедрових сосен в ДПТНЗ «Сновське вище професійне училище лісового господарства»» спрямована на розкриття проблеми вирощування цінних в поживному та лікувальному відношенні кедрових сосен в умовах Чернігівського Полісся. Сьогодні лісовідновлення є пріоритетним завданням для лісової політики нашої держави, але багато питань є невирішеними, зокрема, проектування процесу розширення видового складу деревних порід, які є перспективними в озелененні, харчовій та медичній сферах. Автором проаналізовано стан вивчення питання на основі 37 літературних джерел. У ході дослідження автором було обґрунтовано доцільність та розраховано вартість створення плантації сосен- інтродуцентів.
Qualification work Kompanets R.A. "The project of organization of plantation planting of cedar pines in the State Pedagogical University" Snow Higher Vocational School of Forestry "is aimed at revealing the problem of growing valuable in nutritional and medicinal terms cedar pines in Chernihiv Polissya. Today, reforestation is a priority for the forest policy of our state, but many issues remain unresolved, in particular, the design of the process of expanding the species composition of wood species that are promising in landscaping, food and medical spheres. The author analyzes the state of the study on the basis of 37 literature sources. During the study, the author substantiated the feasibility and calculated the cost of creating a plantation of introductory pines.
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Sugarman, David R. "Soil chemical properties in pine plantations of different ages in the Eastern Escarpement region of South Africa". Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/9880.
Testo completoAbstract (sommario):
Bibliography: leaves 71-78.It is widely accepted that afforestation adversely affects soil chemical properties. A significant decrease in pH, base cation status and acid neutralising capacity (ANC), coupled with increasing acidity have been observed to occur in acid coniferous forest soils both in the Northern and Southern Hemispheres. International and local studies in Southern Africa have observed declining productivity over successive rotations in pine plantations. Increasing acidity loads in the Northern Hemisphere and their adverse effects on forest health have generated a search for chemical indices that would assist in pursuing thresholds beyond which forest vitality is damaged. A common and widely used chemical index is the Ca/Al ratio. The most common parameter adopted is the Ca/Al molar ratio in soil solutions. Recent studies in Southern Africa (Swaziland. Kwazulu-Natal) and in the Sabie area (Eastern Escarpment) have indicated that some forest compartments (Pinus sp.) may experience Ca/Al molar ratios dropping below unity. The value of unity is widely used and proposed as a threshold beyond which tree vitality may be adversely affected. This study was conducted to determine the state of surface (0-20cm) soils underlying pine plantations of different ages in the Sabie area on the Eastern Escarpment of Southern Africa. The pine plantations were selected in areas overlying a uniform bedrock (shale), high attitude, high rainfall, north facing aspect and confined to 3 pine species (P. elliottii, P. patuia and P. taeda). A composite sample was taken from each of 22 forest compartments varying in age (between 22 and 67 years) and rotation (first, second and third). In addition, the results of previous investigations of forest soils in the Eastern Escarpment region were considered in order to expand the array of forest compartment ages and the size of the overall data set used for statistical analysis, so that comparisons could be made.
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Fettig, Christopher John. "Development and evaluation of trapping studies for Hylobius pales (Herbst) and Pissodes nemorensis Germar (Coleoptera: curculionidae) in Virginia Christmas tree plantations". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02132009-171844/.
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Zaloumis, Nicholas Paul. "How successful is grassland restoration after removal of pine plantations on the eastern shores of Lake St Lucia?" Bachelor's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/26044.
Testo completoAbstract (sommario):
The coastal grasslands that occur along the Eastern Shores of Lake St. Lucia are rich in plant species, including endemics. These grasslands in North KwaZulu-Natal, South Africa, are remnants of a severely threatened vegetation type. Large portions of the Eastern Shores have been utilized for commercial pine plantations over the last 50 years; however these have been removed over the last 17 years. It is therefore important that efforts to restore grasslands that have been previously afforested stands of pines are successful. These grassland systems are fire driven and therefore many plants have adapted to these conditions by having massive storage organs below the ground. Using several response variables I was able to assess the effects of plantations on alpha- and beta-diversity and functional traits of forb and other grassland species and attempted to determine whether these disturbed grassland were returning to their original state. A high level of community heterogeneity was found at both scales for natural vegetation, while more homogenous, species low patterns were seen in post-plantation sites. Most notable was the large number of missing resprouting species in pine sites and that, in contrast to forest rehabilitation studies, no evidence for succession was found. The implication of this is massive as grassland rehabilitation may be a lot harder than was previously thought. It is likely that the fire adapted forb species are bad colonizers and have struggled to return to disturbed sites. These grasslands are therefore susceptible to activities that remove or eliminate the considerable amount of below ground biomass from the soil, and these sorts of disturbances should be avoided. Active rehabilitation methods will be required if any progress is going to be made and until such methods are effective considerable effort should be made in conserving the remaining grasslands that we have left and promoting its pharmaceutical, horticultural and societal value.
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Kiser, Larry Christopher. "Nutrient Retention and Cycling in Southeastern U.S. Loblolly Pine (Pinus taeda L.) and Sweetgum (Liquidambar styraciflua L.) Plantations". Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/28989.
Testo completoAbstract (sommario):
Forest plantations in the southeastern U.S. are fertilized to increase growth on infertile, sandy soils. Nitrogen (N) and phosphorus (P) are the most common growth limiting nutrients. A key question that arises following fertilization of these soils is whether the applied fertilizer benefits only the current trees in the stand or also improves long-term site quality. The objectives of this study were to compare accumulation of N and P in the forest floor and mineral soil among unfertilized and fertilized plantations, determine soluble and residual N and P fractions and soluble carbohydrate and phenol fractions in foliage and litter, determine whether higher N in the forest floor from fertilization resulted in increased release of N from the forest floor and increased mineral soil N availability, and determine loblolly pine forest floor decomposition rate and release of nutrients in a simulated disturbance environment. Research was conducted at a 25-year old loblolly pine (Pinus taeda L.) plantation in NC (SETRES) and 13-year old loblolly pine and sweetgum (Liquidambar styraciflua L.) plantations in GA (Mt. Pleasant). Fertilization resulted in increases in mineral soil N that were likely to be temporary and not sustained following cessation of fertilization N applications. This was likely due to an inability of acidic, sandy mineral soils to retain NH4-N and NO3-N. The forest floor accumulated N due to slow release of N during decomposition. Fertilization with N results in only temporary increases in mineral soil N availability that occur during fertilizer application and from forest floor decomposition. Future changes in N availability are primarily determined by decomposition of the forest floor following a disturbance that accelerates decomposition. In contrast to N, fertilization of loblolly pine and sweetgum with P results in a long-term increase in site P availability. Fertilization with P has lasting effects by increasing mineral soil P in stable forms that can be made available for plant uptake over time suggesting increased supply of P to trees in the next rotation. Retention of P in the mineral soil was likely due to the tendency of acidic, sandy mineral soils to accumulate P in Al- and Fe-phosphates.Ph. D.
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Hauser, James W. "Effects of hydrology-altering site preparation and fertilization/release on plant diversity and productivity in pine plantations in the coastal plain of Virginia". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042010-020225/.
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Thomson, Roberto F. "Response of temperate forest birds to habitat change in central Chile". Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1792418e-18e9-4344-96ce-3bad2aa03500.
Testo completoAbstract (sommario):
Despite the long time since the introduction and spread of pine plantations in southern hemisphere countries there has been no study of the suitability of this exotic and novel type of vegetation on the native avifauna. This thesis aims to add understanding of this habitat replacement and its effects on the forest bird community. This research included a series of studies to assess the quality of mature pine plantations for the forest avifauna in comparison to what is in native forests. The first two studies determine the effects on the forest bird community of the fragmentation and replacement of native forest in a gradient of substitution. The results showed a direct relationship between level of substitution and loss of functional diversity, and that fragmentation predicts the bird assemblage in pine stands. The next two studies used data from an intensive ringing season to assess differences in the condition of populations inhabiting each habitat. Birds, in general, were found in better condition in native fragments than in pine plantations. Moreover, a despotic distribution was determined for a migrant species and a gradient in habitat quality was found in relation to proximity to native forest. The next two studies used information from a nest-box survey set in a gradient of sites with substitution of native forest. The results showed that the type of forest cover and their proportion in the landscape may affect the breeding performance of some species. Finally, in the last study I evaluated the foraging niche of bird species in each habitat. Compared with native forest, niche breath reduced while the niche overlap increased in pine plantations for most species. The results suggest that pine plantations are poor quality habitat for the bird community and that the substitution of native forests increases selective pressure.