Treesearch

Multispectral satellite imagery are appealing for their relatively low cost, and have demonstrated utility at the landscape level, but are typically limited at the stand level by coarse resolution and insensitivity to variation in vertical canopy structure. In contrast, lidar data are less affected by these difficulties, and provide high structural detail, but are less available due to their comparatively high cost. Two forest structure attributes measured at the plot level, basal area and trees per hectare, were predicted using stepwise multiple regression on 40 predictor variables...

Land managers need cost-effective methods for mapping and characterizing forest fuels quickly and accurately. The launch of satellite sensors with increased spatial resolution may improve the accuracy and reduce the cost of fuels mapping. The objective of this research is to evaluate the accuracy and utility of imagery from the advanced spaceborne thermal emission and reflection radiometer (ASTER) satellite sensor, and gradient modeling, for mapping fuel layers for fire behavior modeling with FARSITE and FLAMMAP. Empirical models, based upon field data and spectral information from an...

Whitebark pine (Pinus albicaulis Engelm.), an important component of high elevation ecosystems in the western United States and Canada, is declining due to fire exclusion, white pine blister rust (Cronartium ribicola J.C. Fisch.), and mountain pine beetle (Dendroctonus ponderosae Hopkins). This study was conducted to evaluate the effects of whitebark pine restoration treatments on the distribution of bark beetle attacks. At a site in Idaho, silvicultural treatments were implemented in summer 1998 and 1999, with prescribed burning implemented in Oct. 1999. Permanent plots (400m2) were...

The sagebrush (Artemisia spp.) ecosystem once occupied over 150 million acres of western North America (Barbour and Billings 1988). The ecosystem still occupies over 100 million acres (Connelly et al. 2004, Wisdom et al. 2005), but the abundance and condition of sagebrush communities is declining rapidly in response to a variety of detrimental land uses and undesirable ecological processes (Knick et al. 2003). The ecosystem has been reduced in area by 40-50 percent since pre-European settlement (Connelly et al. 2004), and less than 10 percent remains in a condition unaltered by human...

Recent projections of climatic change have focused a great deal of scientific and public attention on patterns of carbon (C) cycling as well as its controls, particularly the factors that determine whether an ecosystem is a net source or sink of atmospheric carbon dioxide (CO2). Net ecosystem production (NEP), a central concept in C-cycling research, has been used by scientists to represent two different concepts. We propose that NEP be restricted to just one of its two original definitions-the imbalance between gross primary production (GPP) and ecosystem respiration (ER). We further...

Community based monitoring (CBM), a form of citizen science, is presented as a potential contributor to ecosystem management and sustainable development. A conceptual model for CBM and lessons learned from a Canadian national pilot program, the Canadian Community Monitoring Network, are summarized along with a description of the European university-based “science shop” approach. Local knowledge can be legitimized and validated through CBM programs, and participants are empowered to engage in the adaptive policy, planning, and management processes that affect their communities. Ranchers in...

Coyotes have expanded their historical distribution range because of anthropogenic activities and habitat transformation, where forests have been considered marginal habitat. We tested the relationship between vegetation structure and coyote abundance in different habitat types. We expected to find a higher abundance in open lands than in thicker areas. We used scent station surveys and found that the shrub layer seems to be the factor determining coyote abundance, with a higher use of open areas. The structure of the vegetation represents an important factor in the distribution and...

In the field of spatially explicit modeling, well-developed accuracy assessment methodologies are often poorly applied. Deriving model accuracy metrics have been possible for decades, but these calculations were made by hand or with the use of a spreadsheet application. Accuracy assessments may be useful for: (1) ascertaining the quality of a model; (2) improving model quality by identifying and correcting sources of error; (3) facilitating a comparison of various algorithms, techniques, model developers and interpreters; and, (4) determining the utility of the data product in a decision-ma...

Wilderness areas are primarily set aside to protect natural ecosystems and processes. However, most protected areas have a long history of native peoples' land use predating their protection. The general paucity of evidence in the form of historical records, in combination with romantic views of native peoples' effects on nature, often leads to their impact being underestimated. The analysis of culturally modified trees in protected old-growth forests has increasingly been recognised as an important tool for analyzing long-term trends in native peoples' land use. The aim of this study was...

Chiricahua fox squirrels (Sciurus nayaritensis chiricahuae) are endemic to the Chiricahua Mountains of southeastern Arizona. A paucity of natural history information and uncertain conservation status served as impetus for us to initiate a descriptive ecological study of the species. We examined reproductive and population ecology of Chiricahua fox squirrels intermittently from 1994 to 2003. Chiricahua fox squirrels appear to possess 10 of 13 attributes associated with vulnerability to extinction, including low population densities and reduced reproductive capacity. We underscore potential...