The forests of Hluhluwe Nature Reserve, Kwa Zulu-Natal, were examined to determine composition, grain, classification, dynamics and conservation value. Field sampling took the form of recording DBH for all species in twenty-one 0.04 ha circular plots, walking 5-metre wide transects in mature and marginal forest to record size-classes and analysis of twenty gaps. Data were analysed by the multivariate programs, TWINSPAN and CANOCO. The composition of the canopy and subcanopy is distinct. Four canopy and two subcanopy communities can be detected. Community succession in the mature forest takes the form of almost random replacement of canopy trees through two subcanopy communities. Size-class distributions indicate a prevalence of shade-intolerant species. This forest is deemed to be coarse-grained and can be classified as coastal scarp forest. Comparisons with other forests shows Hluhluwe to have slightly above average species richness. A removal of anthropogenic disturbance by the creation of the reserve may have resulted in present forest canopy structure. Management for conservation of species diversity should encourage disturbance. There is potential for harvesting of certain shadetolerant species by local communities. This forest is a pristine fragment of a rapidly diminishing vegetation type and efforts should be made to conserve its entire expanse, within Hluhluwe Nature Reserve, in order to prevent species loss.

The most widespread way of extraction of forest is still clearlcuting. It is almost impossible to find commercial forest without forest clearings. Forest clearing can be perceived as a special element in a connected forest. I am trying to find out the influence of these forest distributions on the bird community. I was interested how important the forest clearings will be in the different type of forests. In seven localities were collected set of environmental variability's and bird data, which were counted by point count method. There were deciduous and mixed forests as well as the coniferous monocultures. The data collection was conducted in the breeding season 2011 and 2012. I expected, that the forest glades ensure the heterogeneity in forest space and will increase the number of bird's species. I expected this influence more important in the coniferous than in the deciduous and mixed forests. This assumption was partly confirmed. The glades in the coniferous forests have higher influence, but it depends on the forest area. In large coniferous monocultures is the importance of glades high. In the case of deciduous and mixed forests the size of forests did not have a value. The tree richness has the bigger importance. With this variable correlate Common Chiffchaff, Eurasian Wren, Yellowhammer,...

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Boreal mixedwood forest stands are comprised of a mixture of small canopy patches of varying dominance by conifer (mostly white spruce (Picea glauca (Moench) Voss)) and broadleaf (mostly trembling aspen (Populus tremuloides Michx.) trees. The purpose of this work was to extend our understanding of the patterns and causes of variation in understory vascular plant communities in unmanaged, mature boreal mixedwood forests. First, I assessed variation in understory community composition in relation to canopy patch type (conifer, mixed conifer-broadleaf, broadleaf, gaps) within mixedwood stands. The mosaic of canopy patches leads to different micro-habitat conditions for understory species, allowing for communities that include both early and late successional species and contributing to greater understory diversity. This study suggests that the mosaic of small canopy patches within mixed forest stands resembles a microcosm of the boreal mixedwood landscape, across which understory community composition varies with canopy composition at the stand scale. Second, I investigated the hierarchical organization of understory diversity in relation to the heterogeneous mosaic of canopy patch types through additive partitioning of diversity. The largest proportion of species richness was due to turnover among patches within patch type while individual patches had higher evenness. The mosaic of canopy patch types within mixedwood forests likely plays a crucial role in maintaining the hierarchical levels at which understory diversity is maximized. Third, I examined interactions among understory plant species by investigating the effect of shrub removal on biomass, composition and diversity of herbs using a 3-yr removal study in a natural understory community. There is asymmetric competition for light between erect shrub and herb species but herb response to erect shrub removal was species-specific. Plant interactions play an important role in structuring boreal understory communities. Finally, I explored the relative influence of space, environmental variables, and their joint effects, on understory composition and richness. The environmental variation caused by small canopy patches and biotic processes, such as species interactions, converge at the fine scale to create a spatially patchy structure in understory communities in boreal mixedwood forests. Modifications in the natural mixture of small canopy patches could disrupt the spatial and environmental structures that shape understory composition and diversity patterns. / Forest Biology & Management

Boreal mixedwood forest stands are comprised of a mixture of small canopy patches of varying dominance by conifer (mostly white spruce (Picea glauca (Moench) Voss)) and broadleaf (mostly trembling aspen (Populus tremuloides Michx.) trees. The purpose of this work was to extend our understanding of the patterns and causes of variation in understory vascular plant communities in unmanaged, mature boreal mixedwood forests. First, I assessed variation in understory community composition in relation to canopy patch type (conifer, mixed conifer-broadleaf, broadleaf, gaps) within mixedwood stands. The mosaic of canopy patches leads to different micro-habitat conditions for understory species, allowing for communities that include both early and late successional species and contributing to greater understory diversity. This study suggests that the mosaic of small canopy patches within mixed forest stands resembles a microcosm of the boreal mixedwood landscape, across which understory community composition varies with canopy composition at the stand scale. Second, I investigated the hierarchical organization of understory diversity in relation to the heterogeneous mosaic of canopy patch types through additive partitioning of diversity. The largest proportion of species richness was due to turnover among patches within patch type while individual patches had higher evenness. The mosaic of canopy patch types within mixedwood forests likely plays a crucial role in maintaining the hierarchical levels at which understory diversity is maximized. Third, I examined interactions among understory plant species by investigating the effect of shrub removal on biomass, composition and diversity of herbs using a 3-yr removal study in a natural understory community. There is asymmetric competition for light between erect shrub and herb species but herb response to erect shrub removal was species-specific. Plant interactions play an important role in structuring boreal understory communities. Finally, I explored the relative influence of space, environmental variables, and their joint effects, on understory composition and richness. The environmental variation caused by small canopy patches and biotic processes, such as species interactions, converge at the fine scale to create a spatially patchy structure in understory communities in boreal mixedwood forests. Modifications in the natural mixture of small canopy patches could disrupt the spatial and environmental structures that shape understory composition and diversity patterns. / Forest Biology & Management

<p> The pollen, charcoal and sediment stratigraphies of two cores from small lakes located northeast of Yellowknife, NWT are examined. The focus of this study is to reconstruct post-glacial vegetation changes in this climatically sensitive area. The resulting vegetation history is compared to similar reconstructions from across Canada. The pollen content of twenty-eight modern sediment samples, collected from the forest, the forest-tundra and the tundra zones were used to aid in the interpretation of the fossil record. Radiocarbon dates indicate that the fossil records from these lakes span ~7 500 years. The initial vegetation, shrub Betula tundra, was established at ~7 000 BP and persisted until ~6 000 BP. The presence of Ericaceae, Myrica, and Sphagnum distinguishes this zone from similar zones from western Canada and suggests the existance of large areas of bog environment. This zone is succeeded by a second shrub tundra zone, which is marked by a dramatic increase in Alnus crispa and Alnus incana. This zone spans from ~6 000 BP until ~5 000 BP. A synchronous increase in Alnus is noted from sites across Canada and is attributed to an increase in moisture. The third zone, spanning from ~5 000 BP to ~3 500 · BP, delimits the existance of forest vegetation defined by the northward expansion of Picea mariana. The delay of Picea mariana expansion into the area relative to its arrival in western Canada can be explained by one of the following: 1) geological differences; or 2) remnant glacial ice retarding climatic amelioration; or 3) the long-wave westerly disturbance, which causes cooler temperatures in the east when warmer temperatures persist in western Canada; or 4) some combination of the above. The decline of forest vegetation at ~3 500 BP marks the establishment of modern tundra vegetation at both sites. Climatic cooling coupled with fire caused the extinction of aboreal vegetation at the study sites.</p> / Thesis / Master of Science (MSc)

Different management regimes consisting of range of site indices and planting densities were simulated to evaluate price premiums required for growing high-quality southern pines across the southern United States. Optimal management regimes were identified maximizing the land expectation value. Growing high-quality pines on longer rotations are economically feasible, however, forest landowners need premiums which ranged from $1.40/ton to $9.81/ton for 10-year rotation extension and increased significantly with rotation ages. In uneven-aged management, price premiums for 5-year cutting cycle extension ranged from $1.75/ton to $2.25/ton. Additionally, sawmill’s willingness-to-pay price premiums for high-quality pine sawtimber were calculated using a mail survey. Sawmills showed a considerable interest in paying price premiums which ranged from $4.22/ton to $12.98/ton. Factors affecting mean WTP price premiums were sawlog size, procurement radius, grade, mill’s capacity, and employees. These findings will help landowners in deciding whether to extend rotation ages of their forest for growing higher quality pines.

The FVS-Sn model was developed by the USDA Forest Service to project and report forest growth and yield predictions for the Southern United States. It is able to project forest growth and yield for different forest types and management prescriptions, but it is a relatively new, complex, and untested model. These limitations notwithstanding, FVS-Sn once tested and validated could meet the critical need of a comprehensive growth and yield model for the mixed hardwood forests of the southern Appalachian region. In this study, sensitivity analyses were performed on the FVS-Sn model using Latin hypercube sampling. Response surfaces were fitted to determine the magnitudes and directions of relationships between FVS-Sn model parameters and predicted 10-year basal area increment. Model sensitivities were calculated for five different test scenarios for both uncorrelated and correlated FVS-Sn input parameters and sub-models. Predicted 10-year basal area increment was most sensitive to parameters and sub-models related to the stand density index and, to a lesser degree, the large tree diameter growth sub-model. The testing procedures and framework developed in this study will serve as a template for further evaluation of FVS-Sn, including a comprehensive assessment of model uncertainties, followed by a recalibration for southern Appalachian mixed hardwood forests. / Master of Science

Forest management practices emphasizing stand structural complexity are of interest across the northern forest region of the United States because of their potential to enhance carbon storage. Our research is nested within a long-term study evaluating how silvicultural treatments promoting late-successional forest characteristics affect aboveground biomass development in northern hardwood forests. We are testing the hypothesis that biomass development (carbon storage) will be greater in structural complexity enhancement (SCE) treatments when compared to conventional uneven-aged treatments. SCE treatments were compared against selection systems (single-tree and group) modified to retain elevated structure. Manipulations and controls were replicated across 2-hectare treatment units at two study areas in Vermont, USA. Data on aboveground biomass pools (live trees and coarse woody material, standing dead and downed wood) were collected pre- and post-harvest then again a decade later in 2013. Species group-specific allometric equations were used to estimate live and standing dead biomass and downed log biomass was estimated volumetrically. We used Forest Vegetation Simulator to project "no-treatment" baselines specific to treatment units, allowing measured carbon responses to be normalized relative to differences in site-specific characteristics and pre-treatment conditions. Results indicate that 10 years post-harvest biomass development and carbon storage were greatest in SCE treatments compared to conventional treatments, with the greatest increases in coarse woody material (CWM) pools. Structural complexity enhancement treatments contained 12.67 Mg ha-1 carbon in CWM compared to 6.62 Mg ha-1 in conventional treatments and 8.84 Mg ha-1 in areas with no treatment. Percentage differences between post-harvest carbon and baseline values indicate that carbon pool values in SCE treatments returned closest to pre-harvest or untreated levels over conventional treatments. Total carbon storage in SCE aboveground pools was 15.90% below baseline conditions compared to 44.94% less in conventionally treated areas (P = 0.006). Results from CART models indicated treatment as the strongest predictor of aboveground C storage followed by site-specific variables, suggesting a strong influence of both on carbon pools. Structural enhancement treatments have potential to increase carbon storage in managed northern hardwoods based on these results. They offer an alternative for sustainable management integrating carbon, associated climate change mitigation benefits, and late-successional forest structure.

This paper stresses the existing relationship between the distribution of forest vegetation typologies and forms and relief componentes in the hidrographic basin of the Caverá stream, in the West of the Rio Grande do Sul state, as a subsidy to the discussion of dynamics forest-grassland in that region, using for that geomorphometric variables extracted from SRTM data (Shuttle Radar Topography Mission) and map of vegetation generated through the GIS ArcGIS 10 developed by ESRI, 2013, utilizing images Landsat 8 OLI. This study demonstrated that the relief, through their components, exerts great influence on the distribution and advancement of forest vegetation in predominantly grassland region such as the study area. The hydrographic basin of the Caverá stream, has in its relief, a distinct area of the predominance of the region hills surrounding smooth, that known as Serra do Caverá, has rolling hills and strongly corrugated, with higher declivities that 15% and elevations that reach more than 300 meters. In these portions of the basin, the forest vegetation, principally for capons-of-woods and slopes forests has its most intense occurrence, fact that can be explained by the results obtained in this study. Through the analysis of overlaps and field work in the basin, it was observed that terrain concavities favor, mainly the development of capons-of-wood, whose individuals advanced by the hillsides of hills and morrotes usually through the converging portions of the relief, where there a greater concentration of water, sometimes forming drainage channels. After their establishment on the hillside constituent individuals capons-of-country dissipate also through contacts between volcanic and sandstone rocks, this dynamic occurs constantly until the formation of the slopes forests. The GIS techniques used to study have proved to be appropriate and have allowed the crossing of parameters of the relief and vegetation, demonstrating a important association, especially related to conditions of declivities of slopes and the concentration of water. / Este trabalho busca demonstrar a relação existente entre a distribuição das tipologias de vegetação florestal e as formas e componentes do relevo na bacia hidrográfica do arroio Caverá (BHAC), na região oeste do Rio Grande do Sul, como subsídio à discussão da dinâmica floresta-campo na referida região, utilizando para tal, variáveis geomorfométricas extraídas de dados SRTM (Shuttle Radar Topography Mission) e mapa de vegetação gerado através do SIG ArcGIS 10 desenvolvido pela ESRI, 2013, com o uso de imagens Landsat 8 OLI. Este estudo demonstrou que o relevo, através de seus componentes, exerce grande influência na distribuição e avanço da vegetação florestal em região predominantemente campestre, como é o caso da área de estudo. A bacia hidrográfica do arroio Caverá, possui em seu relevo, uma área distinta da predominância de colinas de ondulamento suave da região, que conhecida como Serra do Caverá, apresenta colinas onduladas e fortemente onduladas, com declividades maiores que 15% e altitudes que chegam a mais de 300 metros. Nestas porções da bacia, a vegetação florestal, principalmente dos capões-de-mato e matas de encosta, tem sua ocorrência mais intensa, fato este que pode também ser explicado pelos resultados obtidos neste estudo. Através da análise dos cruzamentos e trabalhos de campo realizados na bacia, pôde-se observar que as concavidades do terreno favorecem, principalmente, o desenvolvimento dos capões-de-mato, cujos indivíduos avançam sobre as encostas dos morros e morrotes geralmente através das porções convergentes do relevo, onde há maior concentração da água, por vezes formando canais de drenagem. Após seu estabelecimento na encosta os indivíduos constituintes dos capões-de-mato dissipam-se também através dos contatos entre as rochas vulcânicas e areníticas, esta dinâmica ocorre de forma constante até a formação das matas de encosta. As técnicas de SIG utilizadas para o estudo revelaram-se adequadas e permitiram o cruzamento de parâmetros de relevo e vegetação, demonstrando uma importante associação, em especial relacionado às condições de declividade das encostas e da concentração de água.