Treesearch

This is a summary of a 5-year short-term study that evolved into 28 years of long-term research on the US Department of Agriculture, Forest Service's Fraser Experimental Forest in Colorado. The study was begun in 1982 by Forest Service Research Scientists Thomas H. Nicholls and Frank G. Hawksworth to determine the importance of mammal and bird vectors in the long-distance dissemination of lodgepole pine (Pinus contorta) dwarf mistletoe (Arceuthobium americanum), an economically devastating forest disease of western forests. The original vector study evolved into a study of a plant growth...

Montane forests contribute significantly to regional biodiversity. Long-term monitoring data, often located along hiking trails, suggests that several indicator species of this ecosystem have declined in recent decades. Declining montane bird populations have been attributed to anthropogenic stressors such as climate change and atmospheric deposition. Several studies from montane systems have also documented decreased estimates of abundance and reproductive success as well as altered singing rates near hiking trails. Therefore, recreational hiking may be contributing to montane bird...

In Southwestern Spain, multifunctional silvopastoral systems consisting of pastureland and open oak woodlands are known as Dehesas. These, and other similar systems of the Mediterranean basin, are currently threatened by increasing intensive land use. As a consequence, oak regeneration is declining and is in need of adequate management and active restoration. Traditional restoration practices outplant one-year-old, nursery-produced oak seedlings grown in 250­350 cm3 containers, but establishment and growth results are typically poor. This work examines holm oak (Quercus ilex L. subsp....

When the federal agencies established policies in the late 1960s and early 1970s to allow the use of natural fires in wilderness, they launched a natural fire management experiment in a handful of wilderness areas. As a result, wildland fire has played more of its natural role in wilderness than anywhere else. Much of what we understand about fire ecology comes from observations of natural fires in several wilderness areas that have been allowed to burn under a wide range of physical and biological conditions since the 1970s. Wilderness fires have provided valuable datasets for improving...

Wilderness is a relatively new and powerful idea that is still finding its footing in the world of science. Although the intellectual history of wilderness can be traced farther back in time (Nash 2001), as a land classification wilderness is less than a century old, and it was just 50 years ago that wilderness was codified in legislation in the United States. While much of the attention over the past 50 years has been given to the growth and development of the National Wilderness Preservation System and the issue of how much and which lands should be protected as wilderness, it is clear...

At a workshop in Oulanka National Park in Finland, shortly after the Finnish Wilderness Act had passed in 1991, managers and scientists wrestled with how to incorporate science into protection of wildlands of northern Finland. One working group was assigned to develop a list of "why managers don't apply the information scientists provide" and another group worked up an impressive list of "why scientists don't produce the information managers need." A third group was assigned the task of explaining why "sometimes scientific information is valuable, even if it has no immediate management...

Four series of photographs display a range of natural conditions and fuel loadings for grassland, shrubland, oak-bay woodland, and eucalyptus forest ecosystems on the eastern slopes of the San Francisco Bay area of California. Each group of photos includes inventory information summarizing vegetation composition, structure, and loading; woody material loading and density by size class; forest floor depth and loading; and various site characteristics. The natural fuels photo series is designed to help land managers appraise fuel and vegetation conditions in natural settings.

Forests in the Southern Rockies Ecoregion surround the headwaters of several major rivers in the western and central US. Future climatic changes will increase the incidence of wildfire in those forests, and will likely lead to changes in downstream water quality, including sediment loads.We estimated soil loss under the historic climate and two IPCC climate change emissions scenarios (A2 and B1); each scenario was modeled using statistically downscaled climate data from global circulation models (GCMs; ECHAM5 and HadCM3) for each of thirteen land cover types. We used the Revised Universal...

Modern economies rely on central-authority institutions to regulate individual behaviour. Despite the importance of such institutions little is known about their formation within groups. In a public good experiment, groups selected the level of deterrence implemented by the institution, knowing that the administrative costs of the institution rose with the level of deterrence. Results suggest that groups readily self-impose costly deterrent formal institutions. The strictly deterrent institutions implemented here increased contributions sufficiently to completely offset the administrative...

We quantify the vulnerability of water supply to shortage for the Colorado River Basin and basins of the High Plains and California and assess the sensitivity of their water supply system to future changes in the statistical variability of supply and demand. We do so for current conditions and future socio-economic scenarios within a probabilistic framework that incorporates the inherent uncertainties in the drivers of vulnerability. Our analysis indicates that the most sensitive basins to both current and future variability of demand and supply are the Central California and the San...