Summary  In the 1990s a new way of thinking about forestry started. One of the effects of the changing silvicultural practices was that the size of clearcuts became smaller. As the felling areas were reduced in size, the areas where young and older forest meet grew, with this also the occurrence of edge zones increased. An edge can be defined as an interface between different ecosystems, and a forest edge as an interface between forested and non-forested ecosystems, or between two forests of contrasting composition or structure. This edge results in a transition zone in which the adjacent contrasting ecosystems interact - the edge zone. In the edge zone - both abiotic and biotic - processes result in a detectable difference in composition, structure or function of the vegetation near the edge, as compared with the ecosystem on either side of the edge.  This study aimed to increase understanding of occurrence and types of edge zones and their composition on a property, their effect on tree growth, the species diversity of tree and field vegetation. The study was performed on a property of approximately 60 hectares located in southeastern Blekinge. The sampling procedure was based on four transects ranging from 527 to 860 meters in length, which were laid out in south-north direction over the property. Wherever the transect crossed a forest edge, a corridor perpendicular to the edge was laid out. In each corridor a measuring grid dividing the corridor in 10 distance classes of one meter, measured from the forest edge, was laid out. In each distance class tree species were determined, stems counted, and the following variables were measured per tree: height, distance from edge and the diameter at breast height. Data gathering on forest field vegetation was conducted in 1x1 meter plots laid out in the middle of the corridor. Within each sample area, the occurrence of species was noted according to field vegetation type index. For comparing the edge zones to the rest of the estate, reference plots were laid out along the transects between the forest edges. On the property of 60 hectares an estimated 4,2 hectares were influenced by edge effects. All edges were created by anthropogenic processes, there were forest edges with roads and edges created by forestry. Where thinning stands were bordering roads, growth was found to decrease closer to the road. In pre-commercial thinning stands bordering a road the opposite effect was visible. Where old and young productive forest stands bordered, on the young side there was an increase of both tree height as well as diameter further away from the edge. On the old side no edge effect on tree growth was seen. Herbaceous plants, mosses and lichens were more abundant close to the edge in both old and young stands. Borders with roads had the highest diversity of tree and plant species. The field vegetation was found to be more diverse and abundant closer to the edge. The edge zone showed to be of great importance for natural regeneration. In about half the corridors positive, negative or neutral edge effects were found on one or more of the variables: tree height, diameter, basal area, stems per hectare, plants per hectare. These effects were found up to eight meters into the stand. The inventory of tree species and field vegetation showed that different kinds of edge zones give rise to different species compositions. A higher diversity of tree species was found in the edge zone compared to the reference plots. One could use the edge zone for nature conservation purposes as these areas favor biological diversity and constitute interesting environments for species that would otherwise be at risk of being outcompeted in neighboring, more closed spruce forest stands. Keywords: tree growth, diversity, field vegetation, edge zones, edge effect

Nine provenances of Turkish red pine (<i>Pinus brutia Ten</i>.), an eastern Mediterranean conifer, taken from a wide range of locations in Turkey, were grown in individual pots in a greenhouse either with or without joint goose goatgrass (<i>Aegilops cylindrica</i> L.) under either high or low soil water availability for two growing seasons. The study consisted of two separate experiments started at times with varying microenvironmental conditions and Turkish red pine (TRP) provenances. Diameter and secondary needle, stem, and root biomass were measured at the end of the second growing season, while height was measured after both the first and second growing seasons. Pine stem water potential (SWP), measured at the end of the second growing season, was the only physiological variable in the study. / Master of Science

Tree growth influences forest community dynamics and responses to environmental variations, but currently is not well understood. Tree growth in highly diverse wet tropical forests have been well studied and characterised compared to the species-poor dry tropical forests. Thus, it is not clear if growth rates and community dynamics of dry forests are similar to those of wet forests, given the longer dry season, greater rainfall variability, more open canopy and lower number of species in dry forests. This thesis focuses on identifying important factors that influence tree diameter growth rates in the dry tropical forest at Mudumalai, southern India, and also compares growth patterns at this dry forest with those at moister forests. The thesis thus contributes towards closing the gap in understanding of tree growth patterns across the tropics. An initial analysis involving matrix-based population projections of four common canopy species at Mudumalai showed that variations in diameter growth have the potential to drastically modify population trajectories of dominant species. Thus the main focus of this thesis is aimed at identifying the important intrinsic and extrinsic factors affecting growth in this dry forest, as this information could be useful for future management of the forest. The second important aim of the thesis was to find out if growth rates are influenced by different sets of factors in tropical dry versus moist forests. A large permanent 50ha plot vegetation monitoring plot was set up in 1988-89 in the Mudumalai dry deciduous forest, and was subsequently monitored annually by staff of the Centre for Ecological Sciences. Data used in this thesis represent a 12-year interval between 1988 and 2000. Girth measurements were obtained from all woody tree stems ≥1cm in diameter every four years during this 12 year interval, which provided three census intervals of diameter increment data on >13,000 trees. For the comparison between dry and moist deciduous forests, data were obtained from a similar large plot maintained and monitored at the Barro Colorado Island (BCI) in Panama. Influences of the intrinsic factors, tree size, individual identity, species identity and growth form, were examined using t-tests, Wilcoxon signed ranks tests, linear regressions, analysis of variance (ANOVA), principal components analysis (PCA) and cluster analysis. Among the intrinsic factors tested, species identity explained approximately 20% of growth rates at the community level, while tree diameter explained less of growth variation, and growth form had a minor influence on growth. Growth rates also were examined for variations across the three census intervals, and for relationships with rainfall and survival from fire. Statistical tests included t-tests, Wilcoxon and other non-parametric sign tests, logistic regression and ANOVA. Most species and individuals showed significant reductions of growth in the second census interval (1992-1996), and growth rates of most trees were positively related to rainfall. Growth rate variations generally were not related to survival from fire, and few species were capable of escaping fire mortality by fast growth. Spatial environmental influences were tested in the commonest fifteen species, using five habitat categories, local elevation, slope, aspect, and the biotic neighbourhood variables of local conspecific and heterospecific density. Statistical tests included analysis of covariance, multiple linear regression and redundancy analysis. The tests were quadrat-based or individual-based, and species' growth responses were tested at different levels of distance and spatial scale. Topographic features and habitat categories had ephemeral effects on species growth. Only the most dominant species, Lagerstroemia microcarpa, showed consistent conspecific neighbour density effects. Redundancy analysis using a subset of common species and environmental factors did not reveal common growth responses to spatial environmental factors. Comparison of factors influencing growth at Mudumalai versus at BCI using multiple factor ANOVA and multiple linear regressions showed a similar influence of temporal variation at the two sites, but stronger and more widespread influence of tree size (diameter) at BCI. The greater influence of tree size at BCI may be related to greater light limitation in this dense moist forest. Spatial environmental factors had weak influences at both plots. Species were less differentiated from each other at the more diverse BCI plot compared to the relatively species-poor Mudumalai plot, suggesting that species' growth niches may be weakly related to diversity across tropical forests. Overall the results showed that among the factors tested species identity and census intervals were the most important influences on diameter growth at the Mudumalai dry deciduous forest. Tree diameter was less important and less consistent in affecting growth at the Mudumalai dry forest, contrary to expectations based on moist tropical forests where this relationship has been established previously. When comparing Mudumalai and BCI, the relative importance of different factors was different at the two sites, and the most important difference was a dominant influence of light limitation at the wetter forest in Panama. In terms of management applications, this study showed that fires at Mudumalai might be an inescapable source of mortality for many vulnerable species, and improved fire management is crucial for long term survival of species in this dry forest. At a larger scale, light and other environmental variables were found to influence growth differently at Mudumalai compared to BCI. This suggests that location-specific responses may be important for projections of tree biomass and carbon sequestration, especially under future climatic change scenarios.

No description available.

Canopy structure has long been thought to influence the productivity and ecological dynamics of tropical forests by altering the availability of light to leaves. Theories and methods that can connect detailed quantitative observations of canopy structure with forest dynamics, however, have been lacking. There is urgent need to resolve this uncertainty because human-caused climate change may alter canopy structure and function in the Amazon. This work addresses this problem by, first, developing methods based on LiDAR remote sensing of fine-scale structural variation to predict the spatial structure of leaf area and light in forest canopies of the central Amazon (Appendices B&C). I show that LiDAR-based leaf area and light estimates can be used to predict the productivity of tree size groups and one-hectare forest plots--as well as differences between 2 sites separated by 500km (App. B). Sites also differed in canopy structure and the distribution of tree frequencies over size (size or diameter distribution). A model based on tree architecture, however, was able to connect observed differences in canopy architecture with size distributions to predict plot and site differences (App. D). This model showed that tree architecture is plastic in different light environments. While plasticity may increase light absorption, the smallest size groups appeared light limited. Absorption over size groups in one site, but not the other, agreed with the hypothesis of energetic equivalence across size structure. Ultimately, the performance of individual trees of different sizes in different canopy environments links forest demography with canopy structure and ecosystem function--I present a study aimed at improving tests of individual level theories for the role of light dependence in tree growth (App. A). Together, this work quantitatively connects canopy structure with forest carbon dynamics and demographic structure and further develops LiDAR as premier tool for studying forest ecological dynamics. Assessing variation in biomass growth and demographic structure over tropical landscapes with remote sensing will improve understanding of ecosystem function and the role of the Amazon in global Carbon dynamics.

Understanding tree physiological responses to climate change is critical for quantifying forest carbon, predicting species' range change, and forecasting growth trajectories. Continued increases in temperature could push trees into conditions to which they are ill adapted -- such as decreased depth of winter snow cover, altered water regimes, and a lengthened effective growing season. A complicating factor is that in the northeastern United States, climate change is occurring on a backdrop of acid deposition and land-use change. In this dissertation, I used three studies to investigate the spatiotemporal nuances of resultant tree and sapling physiology to environmental change. First, I compared annual growth of co-occurring tree species (sugar maple, red spruce, red maple, yellow birch, and balsam fir) along an elevational gradient on Vermont's tallest peak: Mt. Mansfield. I found baseline differences in growth among species, and many annual variations were associated with species-specific events. Yet, protracted growth patterns, such as recent increases for red spruce and red maple, were correlated with increased temperature and cooling degree days (a heat index). For most species, temperature was positively associated with current growth, but negatively associated with growth the following year. This work demonstrated species' differences in response to change and the complex relationships between growth and temperature. Next, I analyzed how climate, environmental parameters, and site and tree factors related to recent, regional increases in red spruce growth. While there was variability in response to climate and acid deposition by elevation and location, site and tree factors did not adequately explain growth. Higher temperatures outside the traditional growing season were positively related to growth, while nitrogen deposition was strongly negative. However, if nitrogen inputs decline as projected then the strength of this relationship may decrease over time. These results suggest continued favorable conditions for red spruce in the near term as acid deposition declines and temperatures increase, provided precipitation remains adequate to support growth. Lastly, I used a replicated micro-catchment study to examine how four species of tree saplings (paper birch, quaking aspen, American chestnut and black cherry) responded to experimentally elevated temperature (2-4C above control) and reduced early winter snow (first six weeks of winter), depending on soil type. Soil and species characteristics strongly influenced sapling response. However, natural weather patterns during the treatment period were highly variable and muted or exacerbated results. Heating increased the potential photosynthetic period in the fall, causing an overall increase in leaf area. Many two- and three-way interactions of treatment factors were also detected. These outcomes demonstrate the variability in sapling response to a changing climate, as well as the complex interactions that occur among soil, species, and weather parameters.

One of the main elements of dendrochronological standardization is removing the biological trend, i.e. the progressive decline of ring width along a cross-sectional radius that is caused by the corresponding increase in stem size and tree age over time. The ‘‘conservative’’ option for removing this biological trend is to fit a modified negative exponential curve (or a straight line with slope ≤ 0) to the ring-width measurements. This method is based on the assumption that, especially for open-grown and/or shade-intolerant species, annual growth rate of mature trees fluctuates around a specific level, expressed by a constant ring width. Because this method has numerical and conceptual drawbacks, we propose an alternative approach based on the assumption that constant growth is expressed by a constant basal area increment distributed over a growing surface. From this starting point, we derive a mathematical expression for the biological trend of ring width, which can be easily calculated and used for dendrochronological standardization. The proposed C-method is compared to other standardization techniques, including Regional Curve Standardization (RCS), of tree-ring width from ponderosa pines (Pinus ponderosa Douglas ex P.Lawson & C.Lawson) located at the Gus Pearson Natural Area (GPNA) in northern Arizona, USA. Master ring-index chronologies built from ring area, RCS, and C-method reproduced stand-wide patterns of tree growth at the GPNA, whereas other standardization options, including the ‘‘conservative’’ one, failed to do so. In addition, the C-method has the advantage of calculating an expected growth curve for each tree, whereas RCS is based on applying the same growth curve to all trees. In conclusion, the C-method replaces the purely empirical ‘‘conservative’’ option with a theory based approach, which is applicable to individual ring-width measurement series, does not require fitting a growth curve using nonlinear regression, and can be rigorously tested for improving tree-ring records of environmental changes.

Tree-ring formation of eastern white-cedar (Thuja occidentalis L.) at a boreal lake in northwestern Quebec, Canada, was monitored using manual band dendrometers to (i) retrace cambial activity phases, (ii) evaluate the effects of flooding on radial growth, and (iii) analyze the relationships with meteorological factors. The daily circumferential activity of four trees at each of two sites, a riparian and an upland site, was recorded during the growing season of 1996, a year with an extreme spring flood. First cambium cell divisions occurred near June 9, followed by a distinct and sustained upward trend in the stem basal area until mid-July that reflected the earlywood formation. The strongly synchronous circumferential activity at both sites suggests no adverse flooding effect on growth of the riparian trees, which is explained by the rapid retreat of the water just before growth initiation in early June. The following month until mid-August was characterized by strong short-term fluctuations caused by alternating drought and rain periods and a slight downward trend of the basal area for six of the eight banded white-cedars. The dendrometers of two trees, the closest to the lake, showed a slight upward trend probably reflecting latewood formation. Pearson correlation with meteorological data indicated that precipitation was positively related to the daily changes in basal area of all trees except during the period of earlywood formation, which probably resulted from the high soil moisture after spring snow-melting. Mean and minimum air humidity were positively related and maximum temperature negatively related to the daily variations in stem circumference during the whole monitoring period, emphasizing the importance of the internal water status on stem size.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-19T13:33:19Z No. of bitstreams: 1 2016 - Jair Figueiredo do Carmo.pdf: 2232723 bytes, checksum: fe83db2be94c1c93b2be3e9af0a35856 (MD5) / Made available in DSpace on 2017-05-19T13:33:19Z (GMT). No. of bitstreams: 1 2016 - Jair Figueiredo do Carmo.pdf: 2232723 bytes, checksum: fe83db2be94c1c93b2be3e9af0a35856 (MD5) Previous issue date: 2016-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The objective of this research was to study the growth and wood properties of Copaifera langsdorffii trees in an open rain forest, under a forest management system in the state of Mato Grosso, Brazil. Therefore, samples from 20 trees were collected, and the development of the research was divided into two stages. In the first one, a dendrochronological study for the species was carried out and in the second one, a study of the effect of forest management on the anatomical, chemical and physical properties of C. langsdorffii wood. The area where the trees were collected, has as main characteristic the fact that had occurred the first lumbering in 1987 and reaching his second cutting cycle in 2013. During the dendrochronological study, a master chronological series of the tree species and also an analysis of the cambium sensitivity to climatic variations (temperature and precipitation) were done. Furthermore, weather effects of El Ni?o event were found in the growth of those trees. The study of the effect of forest management on the properties of wood, was carried through the anatomical, physics and chemistry characterization of woods that were formed 10 years before and 10 years after the first cutting cycle that had occurred in 1987. It was also analyzed the effect of the distance of the trees studied in relation to the glade (remaining stub) opened in the year of the first lumbering, in 1987. The results indicated that C. langsdorffii has potential to the dendrochronological studies, presenting a significant correlation between the width of the rings within and among those trees. The forest management led to diametrical higher increases than those observed before the first lumbering. It was observed that the higher diametrical growth of trees occurred during periods of the year in which the precipitation rate is higher. The study indicated a significant change in anatomical structure of the wood, by the increased frequency of vessels and decreasing width of rays formed on wood after lumbering in1987. Those results were also observed for the trees distances in relation to the glade. The changes into anatomical structure showed a decrease in the density of the wood formed after 1987. By chemical analysis, 10 chemical elements were found, 4 macro and 6 micronutrients. There was no significant difference in the assimilation of minerals into the wood as a result of forest management. Thus, there was no negative effect on the availability of nutrients to the C langsdorffii. Overall the results showed that forest management was beneficial to the C. langsdorffii, growth because that action led to possible and considerable gains in growth after forest intervention, without incurring significant losses in the anatomical, physical and chemical structure in the wood species. / O objetivo deste trabalho foi estudar o crescimento e propriedades da madeira em ?rvores de Copaifera langsdorffii de uma floresta ombr?fila aberta, sob regime de manejo florestal, no estado de Mato Grosso. Para tanto, foram coletadas amostras de 20 ?rvores, e o desenvolvimento do trabalho foi dividido em duas etapas. Na primeira, foi realizado um estudo dendrocronol?gico para a esp?cie e, na segunda, um estudo do efeito do manejo florestal nas propriedades anat?micas, qu?micas e f?sica da madeira de C. langsdorffii. A ?rea, onde foram coletadas as ?rvores, tem como principal caracter?stica o fato de ter ocorrido a primeira explora??o florestal no ano de 1987 e atingindo seu segundo ciclo de corte no ano de 2013. No estudo dendrocronol?gico, foi constru?da uma s?rie cronol?gica mestre da esp?cie e an?lises da sensibilidade cambial ?s varia??es clim?ticas (temperatura e precipita??o). Al?m disso, verificou-se os efeitos clim?ticos do evento El Ni?o no crescimento das ?rvores. O estudo do efeito do manejo florestal nas propriedades da madeira foi realizado atrav?s da caracteriza??o anat?mica, f?sica e qu?mica dos lenhos formados10 anos antes e 10 anos depois do primeiro ciclo de corte ocorrido em 1987. Foi tamb?m analisado o efeito da dist?ncia das ?rvores estudadas em rela??o ? clareira (toco remanescente) aberta no ano da primeira explora??o de 1987. Os resultados obtidos indicaram que a C. langsdorffii apresenta potencial para estudos dendrocronol?gicos, apresentando uma correla??o significativa da largura dos an?is dentro e entre ?rvores. O manejo florestal propiciou incrementos diametrais superiores aos observados antes da primeira explora??o. Observou-se que os maiores incrementos diametrais das ?rvores ocorreram nos per?odos do ano em que o ?ndice de precipita??o ? maior. O estudo indicou altera??es significativas na estrutura anat?mica da madeira, atrav?s do aumento da frequ?ncia de vasos e redu??o largura dos raios na madeira formada ap?s a explora??o florestal de 1987. Esses resultados tamb?m foram encontrados na an?lise de dist?ncia da ?rvore estudas em rela??o ao toco remanescente. As altera??es na estrutura anat?mica denotaram uma diminui??o da densidade aparente da madeira formada p?s 1987. Atrav?s da an?lise qu?mica foram encontrados 10 elementos qu?micos, sendo 4 macros e 6 micronutrientes. N?o houve diferen?a significativa na assimila??o de minerais na madeira decorrentes do manejo florestal. Assim, n?o houve efeito negativo na disponibilidade de nutrientes para a C. langsdorffii. De modo geral, os resultados encontrados demonstraram que o manejo florestal foi ben?fico para a C. langsdorffii, pois possibilitou ganhos consider?veis de incremento ap?s a interven??o florestal, sem acarretar preju?zos relevantes na estrutura anat?mica, f?sica e qu?mica no lenho da esp?cie.

The influence of salal on tree growth has attained considerable attention in coastal British Columbia. Field observations, surveys, and studies in the CWH zone have indicated poor growth performance of crop tree species in salal-dominated plantations and natural immature and old-growth stands. Where sites have been burned and planted, tree growth has improved; similar effects have been observed for naturally regenerated stands. Immature stands that developed after wind disturbance or harvesting feature rapid growth and nearly complete absence of salal. As studies have shown that ericaceous plants negatively impact tree growth, the salal on potential harvest sites has been considered undesirable. This study examined (1) the possible influence of salal on the stand, soil nutrient status and site index, and (2) the relations between site index, salal, plant communities, and site in disturbed, immature, coastal Douglas-fir ecosystems. We compared vegetation and environmental characteristics of 101 ecosystems, and examined differences in foliar and soil nutrient characteristics and site index between stands with high and low salal cover through analysis of variance (ANOVA) and regression analysis.