Treesearch

Nitrogen (N) deposition and its impact on terrestrial and aquatic ecosystems is a concern facing federal land managers at the Lye Brook Wilderness in Vermont and other protected areas throughout the northeastern United States. In this study, we compared N production in soils with N concentrations and outputs in leachates to determine how forest cover types differ in regulating N losses. Also, precipitation inputs and modeled estimates of streamwater outputs were used to calculate a watershed N budget.

We studied genetic and environmental effects on adventitious root initiation and growth because rooting is biologically prerequisite to the establishment of hybrid poplar plantations. Six clones from two pedigrees (pure Populus deltoides "cottonwoods" and P. deltoides x P. maximowiczii hybrids) were tested at two sites (Alexandria and Fertile, Minnesota, USA) and three planting dates (mid-May, late-May, mid-June, 1999).

The ever increasing demand for forest products and the progressive deterioration of natural forests means that the forest industry cannot continue to rely on the exploitation of natural forests ( Jain, 1997; Tzfira et al., 1998). To meet the increasing demand for forest products while more forest land is needed for non-timber uses, the replacement of natural populations of trees with cultivated varieties is absolutely crucial. At present, short-rotation intensive culture of hardwoods appears to augment this need very well. However, there will be continuous pressure on existing forest lands...

Polyamines (putrescine, spermidine, and spermine) are low molecular weight, open-chained, organic polycations which are found in all organisms and have been linked with stress responses in plants. The objectives of our study were to investigate the effects of chronic N additions to pine and hardwood stands at Harvard Forest, Petersham, MA on foliar polyamine and inorganic ion contents as well as soil and soil solution chemistry. Four treatment plots were established within each stand in 1988: control, low N (50 kg N ha-1 yr-1 as NH4NO3), low N + sulfur (74 kg S ha-1 yr-1 as Na2SO4), and...

Provides current and historical information on primary and secondary hardwood products, production, prices, international trade, and employment.

Provides current and historical information on primary and secondary hardwood products, production, prices, international trade, and employment.

International climate change agreements may allow carbon stored as a result of afforestation and reforestation to be used to offset CO2 emissions. Monitoring the carbon sequestered or released through forest management activities thus becomes important. Estimating forest carbon storage is feasible even for nonindustrial private forestland (NIPF) owners, and the necessary tools are available.We developed a methodology for estimating forest carbon storage at the management unit scale and tested the impacts of hypothetical management scenarios on carbon sequestration over time. We demonstrate...

Several recent studies in landscape ecology have found periodicity in correlograms or semi-variograms calculated, for instance, from spatial data of soils, forests, or animal populations. Some of the studies interpreted this as an indication of regular or periodic landscape patterns. This interpretation is in disagreement with other studies that doubt whether such analysis is valid. The objective of our study was to explore the relationship between periodicity in landscape patterns and geostatistical models. We were especially interested in the validity of the assumption that periodicity...

Nature is socially constructed and many different environmental conditions can be considered natural. These assertions have profound implications for landscape design, planning, and management. In our case study of Whitetop Mountain, we found four discrete but closely related natures - ecotourism, romanticism, pastoralism, and ecologism - each of which provides a unique way of understanding and valuing the landscape.These discourses of nature describe a variety of different environmental conditions that are both possible and acceptable at Whitetop Mountain. Each discourse suggests a...

The nearby natural environment plays a far more significant role in the well-being of children residing in poor urban environments than has previously been recognized. Using a premove/postmove longitudinal design, this research rules out the effects of various extraneous variables that have plagued previous studies and explores the linkage between the naturalness or restorativeness of the home environment and the cognitive functioning of low-income urban children. Both before and after relocation, objective measures of naturalness are employed along with a standardized instrument measuring...