Download or read book Composition Structure and Diversity of Forest Understories Along the Climatic and Edaphic Gradients in the Upper Great Lakes Region written by David K. Foster and published by . This book was released on 1998 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spatial Patterns of Understory Vegetation in Old growth Northern Hardwood Forests written by Todd F. Miller and published by . This book was released on 1999 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1997 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SPECIES COMPOSITION DRIVES ECOLOGICAL STABILITY IN DRY FORESTS OF THE GREAT LAKES ST LAWRENCE FOREST REGION OF ONTARIO CANADA written by and published by . This book was released on 2015 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of species diversity on the stability of ecosystem functions such as productivity, within all spatial and temporal scales, has long been debated in ecology. Extensive research in grassland ecosystems has suggested a positive diversity effect on stability at the community-level due to the insurance hypothesis, but a negative effect at the population-level due to interspecific competition. The few experiments that have investigated the diversity-stability relationship within forest ecosystems have generated inconsistent results, and general conclusions for these systems are currently lacking. Predicted increases in the frequency of short term drought events in the Great Lakes-St. Lawrence (GLSL) forest region of Ontario, Canada, raise concerns about potential effects of climate change on forest ecosystems. The knowledge gap regarding the importance of diversity and composition effects on tree growth in the deciduous-coniferous forest zone of the GLSL must be addressed to anticipate and mitigate some of the effects of climate change in these forests. My dendrochronological research tested the hypotheses that increasing species diversity increases the community-level stability and decreases the population-level stability to a severe short-term drought event in forest tree assemblages typical of dry forests in the GLSL forest region. The assemblages that were studied spanned a gradient of 15 different combinations of species richness and composition of four tree species. The drought that was studied occurred in 2005 and was characterized by high temperature, low precipitation and reduced tree growth. A total of 63 plots representing replicate assemblages were selected to collect increment cores (n=1193) and reconstruct growth responses to past drought at the community and population-levels. The stability of growth of the assemblages was determined by using crossdated tree-ring measurements to reconstruct basal area increment (BAI) and calculate standard indices of resistance, resilience and productivity of the tree communities and populations to the drought. Statistical analysis identified a significant compositional effect on community-level resistance and productivity. White pine ( Pinus strobus L.) abundance was associated with a lower community resistance and white birch (Betula papyrifera Marsh.) abundance with a higher resistance. Assemblages with greater productivity were often characterized by the high abundance of trembling aspen. There was no overall effect of the assemblage gradient on the population-level stability; however, red pine productivity was higher in combination with trembling aspen ( Populus tremuloides Michx.) and white birch. If pine forests were managed to maintain a component of deciduous species, the capacity to dampen the community-level effects of more frequent drought would increase.
Download or read book Fifty Years of Change in Northern Forest Understory Plant Communities of the Upper Great Lakes written by Shannon M. Weigmann and published by . This book was released on 2006 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tree Composition Along Edaphic and Hydrologic Gradients in Nonriverine Wet Hardwood Forests written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We sampled seven intact nonriverine wet hardwood forests to establish target ranges for vegetation, soils and hydrology and to examine trends in plant species composition along a wetness gradient. Although quantitative vegetation analysis for this community has been published, broad drainage classes were used to represent a moisture gradient. We investigated trends along a finer-scaled wetness gradient utilizing a novel wetness index that incorporated indicators of saturated soils. Understanding small-scale patterns in plant community composition is useful in planning wetland restoration projects. Although no strong relationship was found between wetness index classes and plant community composition, these data represent the vegetative community supported by soils specific to each wetness class. Absence of this relationship is most likely a result of the dominance of A. rubrum and L. styraciflua in all wetness classes as well as a history of disturbance in each forest and other unknown stochastic variables. For the restorationist hoping to restore a historic nonriverine wet hardwood forest, once known as oak flats, we can suggest guidelines for restoring hydrology to the wetness classes in which we found oaks with high importance.
Download or read book Structural Gradient Analysis of Upland Forests in the Western Great Lakes Area written by F. Glenn Goff and published by . This book was released on 1968 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tree Composition Along Edaphic and Hydrologic Gradients in Nonriverine Wet Hardwood Forests written by Tracy Catharine Morris and published by . This book was released on 2004 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: gradient analysis, hydrologic gradient, hydric soils, nonriverine wetlands.
Download or read book The Structure and Diversity of Herbaceous Understory Communities in Temperate Deciduous Forest written by Susan Bratton and published by . This book was released on 1975 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forest Structure and Composition Changes in a Tropical Montane Cloud Forest Surrounding an Illegal Village in Bale Mountains National Park written by Theresa Ramona Arechiga and published by . This book was released on 2014 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bale Mountains National Park (BMNP) is currently considered the most important conservation area in Ethiopia. BMNP was established over forty years ago to protect Ethiopian endemic fauna and to preserve an array of habitat types including Afroalpine, Afromontane, and the second largest natural humid forest (Harenna forest) left in Ethiopia. In the 1980's and 1990's assertions of a potential seasonal tropical montane cloud forest were made concerning areas in the upper Harenna forest. Despite these claims no additional evidence or research has been provided to verify the presence of a tropical montane cloud forest. Since the initial claims BMNP has faced increasing human and livestock population growth throughout the park including the elevation belt believed to contain the tropical montane cloud forest. This observational study was undertaken in Rira, the largest permanent village in the 2700 m to 3200 m above sea level belt. There were two goals to this research: one, to document rainfall amounts, temperature averages, and provide evidence of forest structure and characteristics consistent with tropical montane cloud forests; second, to identify the strongest detectible gradients affecting current forest structure and composition of herbaceous, shrub, and tree communities. A stationary weather station was installed at BMNP Subheadquarters at 2800 m to collect pertinent weather data. Variable-radius plots and fixed area plots were used along forest resource trails to collect the vegetation data. Nonmetric Multi-dimensional Scaling (NMS) was used to identify important gradients affecting forest structure and composition in the forest surrounding Rira. The vegetation matrix consisted of percent cover for the herbaceous layer, basal area and count for shrubs, basal area and size classification information for the trees, which resulted in a 15 plot x 96 species matrix. Twenty-three environmental and anthropogenic variables were used in a second matrix to identify primary gradients influencing the vegetation structure and composition. Average monthly rainfall in Rira was 673 mm based on 18 months of rainfall data. The overall forest canopy height and physical characteristics are consistent with tropical montane cloud forests. These findings suggest that the upper portion of the Harenna forest should be officially classified as tropical montane cloud forest. The primary gradient affecting forest structure and composition was consistent with anthropogenic disturbance. The variables which were statistically significant covariates included herbaceous layer height, distance to village, and presence of fuel wood collection with Pearson's r (13) = -0.86, -0.84, 0.82, p
Download or read book Mixed species Forest Ecosystems in the Great Lakes Region written by and published by . This book was released on 2002 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Great Lakes Forest written by Susan Flader and published by U of Minnesota Press. This book was released on 1983 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book UNDERSTORY DYNAMICS ACROSS 62 YEARS OF A NORTHERN HARDWOOD MANAGEMENT GRADIENT STUDY written by and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Northern hardwood selection silviculture relies on the perpetuation of natural regeneration. However, many researchers and forest managers have concerns about deficiencies in regeneration and the associated ingrowth and recruitment of advance regeneration under single-tree selection. Given the differences of management application in the Great Lakes region, long-term studies and datasets are critical to understanding of how these systems function and change. Using the Cutting Methods Study, in the Western Upper Peninsula of Michigan, these concerns were investigated with a multi-decadal dataset, for understory tree species composition and density, diversity, recruitment, and age-diameter relationships across management methods. In response to the past three harvest entries, regeneration densities have consistently been affected by overstory basal area; with a positive relationship in the smallest size classes which gradually flatten in the larger size classes. All treatments had a decline in understory sugar maple dominance with the largest changes in the high intensity treatments which also supported the highest species diversity. Moreover, all treatments have a positive age-diameter relationship with a trend of lower recruitment rates in low intensity treatments, and have created and recruited regeneration since the study establishment in 1956. Following 62-years of consistent management, these results suggest that alternative management methods, beyond Arbogast (1957) recommendations, can be applied in comparable northern hardwood forests and can maintain similar regeneration densities with higher species diversity and recruitment.
Download or read book Site Index Comparisons for Forest Species in the Upper Great Lakes Area of the United States and Canada written by Willard H. Carmean and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Needs in the Forest Economy of the Upper Great Lakes Region written by Hereford Garland and published by . This book was released on 1966 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drivers of Plant Diversity and Distribution in a Northern Hardwood Forest Interacting Effects of Biotic and Abiotic Factors written by Raleigh Dean Ricart and published by . This book was released on 2019 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The drivers of plant diversity and community composition are often influenced by deterministic mechanisms, such as existing environmental conditions, including landscape-level topographic features. In addition, evidence suggests that stochastic mechanisms can also play a critical role in plant community assemblage. Therefore, I investigated how diversity and composition are distributed through space in a mid- successional mixed hardwood forest in northern lower Michigan, USA. This region has been heavily influenced by its glacial past, which resulted in geographically and abiotically distinct glacial landforms that have been shown to influence spatial dynamics of forest communities. Vegetation sampling plots (n=87) were established at the University of Michigan Biological Station (UMBS). Vegetation data of the overstory (>9cm dbh), sapling (1.5-9cm dbh) and groundcover (% cover) layers were collected. Abiotic variables, including elevation, pH, and soil nutrients, were collected in a subset of plots (n=40). I conducted various multivariate statistical analyses to assess the difference in plant communities and abiotic condition, including ANOVA, Variation Partitioning, PERMANOVA, NMDS, and RDA. Variation Partitioning results demonstrated that both deterministic and stochastic mechanisms influenced the community composition of all vegetation layers, however the overstory was mostly influenced by stochastic mechanisms, while the sapling and groundcover layers were opposite. ANOVA results showed strong differences in diversity between glacial landforms. Additionally, PERMANOVA and Non-metric Multidimensional Scaling (NMDS) showed strong differences in community composition between the glacial landforms. Redundancy Analysis (RDA) revealed a strong influence of abiotic variables on composition, with the strongest effects coming from elevation and O horizon depth (O_depth). My findings indicate a large influence of glacial landforms on the production and maintenance of local plant diversity and community composition in this area. Plant diversity and composition are also strongly influenced by successional dynamics following a disturbance event. Moreover, spatial and temporal dynamics are interactive, and rates of successional advancement can be variable depending on underlying spatial gradients. I investigated how diversity and composition are distributed through time using the same system and vegetation data described above. However, vegetation sampling plots were censused in 1990 and again in 2015, which allowed for me to track compositional change over a 25-year-period. ANOVA results showed relatively stable levels of species diversity between census periods. In addition, PERMANOVA results revealed very little difference in community composition over the twenty-five-year period. Furthermore, we found no evidence of differences in successional rates between landforms. My findings suggest that successional dynamics may manifest themselves over much longer time periods in these northern biomes. Finally, I tested the effects of competition of Pteridium aquilinum (“bracken” fern) on the growth and survival of two prominent tree seedlings, Pinus strobus and Acer saccharum. Furthermore, I was interested in how above- and belowground competition from bracken varied across a fertility gradient. Twelve plots were established in four bracken-dominated stands at the UMBS. Seedlings of both species were subjected to one of the following treatments: aboveground competition removal, belowground competition removal, above- and belowground competition removal, and control. Each replicate was a split-plot design, where the soil fertility in half of the plot was altered using nitrogen fertilizer. Differences across collected variables were analyzed using ANOVA. Bracken had an overall negative effect on the growth of both seedlings, with significantly lower values for Relative Growth Rate in both shoot and root biomass under full bracken- competition treatments. There was no difference between fertility treatments, suggesting that competitive strategy does not change with increased availability of soil nitrogen. Finally, there was a significant difference between the overall performance of the two species, where P. strobus outperformed A. saccharum across most of the collected variables. This suggests a possible species-specific “filtering effect” of bracken that may have long-term consequences for the composition of future forests in the area.
