Treesearch

Sugar maple, an abundant and highly valued tree species in eastern North America, has experienced decline from soil calcium (Ca) depletion by acidic deposition, while beech, which often coexists with sugar maple, has been afflicted with beech bark disease (BBD) over the same period. To investigate how variations in soil base saturation combine with effects of BBD in influencing stand composition and structure, measurements of soils, canopy, subcanopy, and seedlings were taken in 21 watersheds in the Adirondack region of NY (USA), where sugar maple and beech were the predominant canopy...

In 1950, the US Forest Service initiated a cutting practice level (CPL) study on the Penobscot Experimental Forest in Maine on the basis of findings of a national appraisal of forestland management. Silvicultural treatments, including the selection system with 5- and 15-year cutting cycles, fixed diameter-limit cutting, and variants of commercial clearcutting, were chosen to represent "High-order," "Good," "Fair," and "Poor" cutting practices as then defined for eastern spruce–fir (Picea–Abies; northern conifer) forests. After 60 years, selection treatments have maintained a wide distributi...

American Indian tribes have inherent rights to national forestland and resources codified in treaties, the US Constitution, statutes, Presidential Executive Orders, and case law. These rights require a government-togovernment relationship between each tribe and the US Forest Service (USFS), which recognizes federal trust responsibilities and tribal sovereignty. This is implemented through government-to-government consultation. Along with consultation, the USFS seeks to create opportunities to work in partnership with tribes to support natural resource management for mutual benefit. The...

Childhood-nature experiences have lifelong effects on environmental citizenship and commitment to nature-based activities. But, it is unclear whether, and to what extent, the different mechanisms through which children and youth experience nature are associated with these outcomes. To test these associations, an online questionnaire assessing mechanisms of childhood exposure to nature, adulthood environmental citizenship and commitment to nature-based activities, and demographic variables was sent to the email addresses of 509 employees of the United States Department of Agriculture,...

In order to protect and understand the regeneration of riparian forests, it is important to understand the environmental conditions that lead to their vegetation differentiation. We evaluated the structure, composition, density and regeneration of woody species in forests along the river Safaroud in Ramsar forest in northern Iran in relation to elevation, soil properties and distance from the river. Using 60 transects located perpendicularly to river and 300 quadrats, we examined forests 0, 50, 100, 150 and 200 m from the stream along an elevation gradient spanning from 350 to 2,400 m...

This photograph (Fig. 1), taken in June of 1923 by E.S. Ship, depicts a red spruce (Picea rubens) stand with advanced reproduction near the summit of Mount Mitchell in the Pisgah National Forest of North Carolina. According to Hopkins (1899), the original extent of red spruce encompassed as much as 1,500,000 ac in the southern Appalachians; by 1895, this had been reduced to 225,000 ac. To help restore this ecosystem, the Appalachian Forest Experiment Station (AFES) was established in 1921. Headquartered in Asheville, North Carolina, the AFES covered an area of 120 million ac in Maryland,...

Background and aims. Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. We aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile. Methods. We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period,...

Cities are increasingly greening vacant lots to reduce blight. Such programs could reduce inequities in urban greenspace access, but whether and how greened lots are used remains unclear. We surveyed three hundred greened lots in Philadelphia for signs of use and compared characteristics of used and nonused lots. We found physical signs of use that might be found in yard space, such as barbeques, picnic benches, and swings, on approximately 10 percent of lots. Logistic regression showed that population density was the only statistically significant predictor of lot use. Findings suggest...

Many studies have examined short-term changes in understory vegetation following prescribed burning. However, knowledge concerning longer term effects on both forest understory and overstory vegetation is lacking. This investigation was initiated to examine changes in understory (herbaceous and shrub) and overstory species composition almost four decades after logging and prescribed burning at the Pike Bay Experimental Forest in Minnesota. The experiment was established in 1964 with a randomized block design with four treatments: control (c); burned in spring 1967 (S0); burned in spring...

Insect outbreaks are major disturbances that affect a land area similar to that of forest fires across North America. The recent mountain pine bark beetle (Dendroctonus ponderosae) outbreak and its associated blue stain fungi (Grosmannia clavigera) are impacting water partitioning processes of forests in the Rocky Mountain region as the spatially heterogeneous disturbance spreads across the landscape. Water cycling may dramatically change due to increasing spatial heterogeneity from uneven mortality. Water and energy storage within trees and soils may also decrease, due to hydraulic...