Treesearch

Prescribed fire is an essential tool that is widely used for longleaf pine (Pinus palustris Mill.) stand management; periodic burning serves to reduce competition from woody shrubs and fire-intolerant trees and enhance herbaceous diversity. Low-intensity, prescribed burning is thought to have minimal long-term impact on soil chemistry in southern pine forests, although few studies report the intra-annual variation in soil chemistry after burning. We monitored changes in C, N, oxidation resistant C (CR), pH and elemental nutrients in the forest floor and soil (0-5, 5-10 cm depths) before...

2,4-Di-tert-butylphenol or 2,4-bis(1,1-dimethylethyl)-phenol (2,4-DTBP) is a common toxic secondary metabolite produced by various groups of organisms. The biosources and bioactivities of 2,4-DTBP have been well investigated, but the phenol has not been systematically reviewed. This article provides a comprehensive review of 2,4-DTBP and its analogs with emphasis on natural sources and bioactivities. 2,4-DTBP has been found in at least 169 species of bacteria (16 species, 10 families), fungi (11 species, eight families), diatom (one species, one family), liverwort (one species, one...

Natural disturbance histories and stand structures derived from old-growth forests are increasingly used to guide forest management prescriptions. Although such information is readily available for a number of forest types, it is lacking for others, such as northern white-cedar (Thuja occidentalis) forests, despite this forest type's wide distribution, ecological value, and economic importance in northeastern North America. We applied standard dendrochronological methods to six old-growth northern white-cedar stands within the Big Reed Forest Reserve of northern Maine, USA, to reconstruct...

Canopy processes at once provide the fundamental building blocks for tree growth, health, and reproduction, and reflect the tree’s ability to adapt to its immediate environment. Foresters’ understanding of these processes informs their decisions about management activities that maintain and enhance forest vigor, health, and biodiversity while providing for desired ecosystem and economic benefits now and into the future. By manipulating density, foresters directly influence availability of light to the remaining trees and indirectly influence available water and nutrients. Forest canopies...

Forests play an essential role in the social, economic, and ecological lives of the inhabitants of the northern United States. Forests cover 69.6 million ha, or 42% of the land area of this region, which is both the most heavily forested and the most densely populated quadrant of the United States (Fig. 1). To preserve a full range of forest ecosystem services into the future, managers are working to identify and implement strategies and tactics that take into account the potentially dramatic effects of a changing climate (Nagel et al., 2010). The region encompasses almost 30° of longitude...

Protecting wildlife within areas of resource extraction often involves reducing habitat fragmentation. In Canada, protecting threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) populations requires preserving large areas of intact forest habitat, with some restrictions on industrial forestry activities. We present a linear programming model that assesses the trade-off between achieving an objective of habitat protection for caribou populations while maintaining desired levels of harvest in forest landscapes. The habitat-protection objective maximizes the amount of...

For decades, federal, state, and nonprofit organizations have been working to restore freshwater habitat for Oregon coastal coho salmon (Oncorhynchus kisutch), a species listed as threatened under the federal Endangered Species Act. Much of the restoration, however, has been done without directly considering the availability and connectivity of seasonally important freshwater habitats. Research by Rebecca Flitcroft, a research fish biologist with the U.S. Forest Service Pacific Northwest Research Station, and colleagues reveals that connectivity among different types of freshwater habitat...

Bearing-tree data were used to calculate an index, pyrophilic percentage, depicting the importance of fire before Euro-American settlement on three landscapes, two within the Prairie Peninsula and one outside the region. Based on functional traits, bearing trees were classified as either pyrophilic or pyrophobic, applied to Public Land Survey points, and the pyrophilic percentage was calculated for each point. Kriging was applied to this point database to create a continuous surface of pyrophilic percentages. Regression analysis was used to relate this surface to environmental factors....

Background and Objectives: The structural diversity of an urban forest affects ecosystem service provision, and can inform management, planning, as well as policy. Trunk diameter at breast height (DBH) is amongst the most common measures of tree structure due to its ease of measurement and strong relationships with other structural and non-structural urban forest characteristics. Materials and Methods: In this study, the DBH distributions of urban forests are summarised for 38 American cities with a combined population of over 30 million people and a range of geographic, climatic, and...

Trees impact surface stormwater runoff, soil moisture, streamflow, water quality, and air temperatures by intercepting precipitation (rain and snow), enhancing soil water infiltration, shading surfaces, and evapotranspiring water. These impacts affect human health and well-being. Many of these tree impacts remain to be more accurately quantified and valued, particularly related to water quality aspects such as mass (e.g., sediments), chemical (e.g., nutrients, metals, pesticides), biological (e.g., pathogens, microbes), and thermal loads. Urban trees can help mitigate many of the negative...