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Full-Text Articles in Forest Sciences

Influence Of Silvicultural Treatment, Site Characteristics, And Land Use History On Native And Nonnative Forest Understory Plant Composition On The Penobscot Experimental Forest In Maine, Elizabeth Bryce Aug 2009

Influence Of Silvicultural Treatment, Site Characteristics, And Land Use History On Native And Nonnative Forest Understory Plant Composition On The Penobscot Experimental Forest In Maine, Elizabeth Bryce

Electronic Theses and Dissertations

This study investigates forest understory plant diversity and composition in managed and unmanaged stands within the context of a long-term silvicultural experiment in the Acadian Forest of Maine. I examined the effects of silvicultural intensity and past land use on understory plant species diversity and composition. Silvicultural treatments include three variants of the selection system, three variants of the shelterwood system, modified and fixed diameter-limit cutting, and an unregulated harvest. Two types of unmanaged stands were studied: a continuously forested natural area and secondary forest stands on old fields. Chapter 1 presents analysis of understory plant diversity and composition in …


Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones May 2009

Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones

Open Access Dissertations

Abstract (Summary) Wood turtles ( Glyptemys insculpta ) are of conservation interest rangewide. Anecdotal accounts demonstrate that some populations have been decimated since 1850, and recent studies demonstrate that declines are still underway. From 2004-2008 I investigated the ecology of wood turtles in Massachusetts and New Hampshire. I obtained between one and five years of annual home range data for 150 turtles, and evaluated population structure at 31 sites in five major watersheds. Seasonal floods displaced 7% of wood turtles annually in one watershed, and accounted for elevated mortality. Twelve wood turtles were displaced < 16.8 km, and two were displaced over a 65-foot dam. Several turtles overwintered at their displacement site and two returned successfully, indicating that floods are a mechanism of population connectivity. Several homing turtles ended up in new areas. Turtles occupied stream segments with gradient < 1%, lower than generally available. Agricultural machinery accounted for most observed mortality, followed by automobiles and mammals. Female turtles exhibit smaller home ranges in agricultural areas. Older turtles move farther from the river than do young turtles, possibly reflecting their familiarity with a former landscape. Population density ranged from 0-40.4 turtles/river-kilometer. The highest densities occur in central New Hampshire and lower densities occur in the Housatonic watershed. Population density is negatively correlated with agriculture at both riparian and watershed scales, and responds unimodally to forest cover. Wood turtle populations in western Massachusetts are declining by 6.6-11.2% annually. I estimated ages of turtles by assessing shell-wear rates from photographs. Wood turtles regularly achieve ages over 80 years, and like related species, do not exhibit clear signs of senescence. Old wood turtles are reproductively dominant, and their survival rates are twice as high as young turtles. Carapace scutes appear to require 80 years to become worn. Population modeling indicates that wood turtle populations are declining in New England due to anthropogenic and natural factors. Conservation efforts must address the effects of agriculture on adult survival. Climate change may negatively affect northeastern wood turtles through increased flooding. Populations in mountainous areas may be likely candidates for conservation because they don't occupy prime agricultural land, but may be more susceptible to floods.


The Chemistry Of Acidic Soils In Humid, Temperate Forested Watersheds With Emphasis On Phosphorus, Aluminum And Iron, Micheal Sanclements May 2009

The Chemistry Of Acidic Soils In Humid, Temperate Forested Watersheds With Emphasis On Phosphorus, Aluminum And Iron, Micheal Sanclements

Electronic Theses and Dissertations

Acidification of soils can result from natural processes (i.e. pedogenesis) and from atmospherically derived sulfur (S) and nitrogen (N) which originate from anthropogenic emissions. Research on the effects of acidification has typically focused on base cations, N and aluminum (Al). The Bear Brook Watershed in Maine (BBWM) (a long-term, whole-watershed acidification experiment) demonstrated increased episodic stream export of Al, iron (Fe), and phosphorus (P) in the treated watershed, suggesting that acidification can also affect P. This research evaluates (a) the physical and chemical distribution of P, (b) mechanisms controlling soil P accumulation, mobilization, and availability in humid, temperate forested ecosystems, …


Landscape Ecology Of Large Fires In Southwestern Forests, Usa, Sandra L Haire Feb 2009

Landscape Ecology Of Large Fires In Southwestern Forests, Usa, Sandra L Haire

Doctoral Dissertations 1896 - February 2014

The recent increase in large fires in southwestern forests has prompted concern regarding their ecological consequences. Recognizing the importance of spatial patterns in influencing successional processes, I asked: (1) How do large fires change plant communities?; (2) What are the implications of these changes for ponderosa pine forests?; and (3) What is the relationship of fire severity to gradients of climate, fuels, and topography? To address the first two questions, I studied succession in the woody plant community at two sites that burned in high-severity fire: La Mesa fire in northern New Mexico (1977) and Saddle Mountain in northern Arizona …


Vegetation Response To Restoration Treatments In A Former Pine Plantation In North Florida, Ryan C. Meyer Jan 2009

Vegetation Response To Restoration Treatments In A Former Pine Plantation In North Florida, Ryan C. Meyer

UNF Graduate Theses and Dissertations

As the human population in Florida continues to expand, development follows, and tree farms give way to homes and businesses. As parks are established, restoration of these semi-natural plantations may provide critical habitat for species conservation. This study evaluates vegetation response to restoration treatments at two study sites, formerly tree farms, now preserves in NE Florida. Treatments included thinning, clearing, or control (no treatment) within 10m^2 plots. Thinning reduced tree canopy to 20% (2-3 pines/plot) and removed all other vegetation; clearing treatments removed all biomass to bare soil; no herbicides were used. Within these plots richness and abundance was assessed …