Treesearch

Street trees in San Francisco are comprised of two distinct populations, those managed by the city’s Department of Public Works (DPW) and those managed by private property owners with or without the help of San Francisco’s urban forestry nonprofit, Friends of the Urban Forest (FUF). These two entities believe that the public’s investment in stewardship of San Francisco’s urban forest produces benefits that outweigh the costs to the community. Hence, the primary question that this study asks is whether the accrued benefits from San Francisco’s street trees justify the annual expenditures?

This report quantifies benefits and costs for typical large-, medium-, small-stature, deciduous trees (Fraxinus uhdei, Prosopis chilensis, Acacia farnesiana), as well as a conifer (Pinus halapensis). The analysis assumed that trees were planted in a residential yard site or a public (street/park) site, a 40-year time frame, and a 60% survival rate. Tree care costs were based on findings from a survey of municipal and commercial arborists. Benefits were calculated using tree growth curves and numerical models that consider regional climate, building characteristics, air pollutant concentrati...

Street trees in Cheyenne are comprised of two distinct populations, those managed by the city’s Urban Forestry Division (UFD) and those inspected by the UFD but managed by private property owners. Over the years Cheyenne has invested millions in its municipal forest. The primary question that this study asks is whether the accrued benefits from Cheyenne’s street trees justify the annual expenditures?

Demographic change is redefining the demand for recreation and leisure within North America (Shelhas, 2002; Struglia & Winter, 2002). One such change is a result of rapid Asian American and Hispanic American population growth. A better understanding of the outdoor recreation attitudes and behaviors of those populations and a clearer understanding of how those groups compare to traditional users will provide the basis for more effective management within public recreation services. While very little is known about Asian American recreational behaviors and preferences, researchers have...

The USDA Forest Service National Fire Plan funded a research program to study fire spread in live fuels of the southwestern United States. In the U.S. current operational fire spread models do not distinguish between live and dead fuels in a sophisticated manner because the study of live fuels has been limited. The program is experimentally examining fire spread at 3 scales – the fuel element, the fuel bed, and field scale. Data from the experimental work is being used to test and improve operational (BEHAVE) and research fire spread models (PAGNI, FIRETEC/HIGRAD). The principal live fuels...

A comparative genetic map was constructed between two important genera of the family Pinaceae. Ten homologous linkage groups in loblolly pine (Pinus taeda L.) and Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) were identified using orthologous expressed sequence tag polymorphism (ESTP) and restriction fragment length polymorphism (RFLP) markers. The comparative mapping revealed extensive synteny and colinearity between genomes of the Pinaceae, consistent with the hypothesis of conservative chromosomal evolution in this important plant family. This study reports the first comparative...

As described previously Roads et al. 2001a, hereafter RCF), the Scripps Experimental Climate Prediction Center (ECPC) has been making routine, near-real-time, long-range experimental global and regional dynamical forecasts since 27 September 1997. The global spectral model (GSM) used for these forecasts is that of National Centers for Environmental Prediction’s (NCEP; Kalnay et al. 1996; see also Roads et al. 1999) used for the NCEP–National Center for Atmospheric Research (NCAR) reanalysis. The initial conditions and SST boundary conditions for these experimental GSM forecasts come from...

The response of the introduced red turpentine beetle, Dendroctonus valens LeConte, to host semiochemicals in Shanxi Province, China, was distinctly different from that reported in previous studies conducted in the western part of the native range of D. valens in the central Sierra Nevada, CA. This Þnding suggests either that there is regional variation in D. valens response to host volatiles in North America or that the species underwent rapid adaptation after its introduction into Asia. In the Chinese population of D. valens, (+)-3-carene was the most attractive host monoterpene tested in...

Land use changes, such as deforestation and reforestation, modify not only the organisms inhabiting affected areas, but also above-and belowground environments. Topography further influences local vegetation and environment. Effects of topography and re-establishment of N-fixing koa (Acacia koa A. Gray) trees in +100-yr-old montane grassland on surface soil properties, N pools, and N transformations were assessed using standard and 15N-isotope pool dilution methods. Data were collected for soils on slopes and in drainage bottoms located in grassland, under 9- to 11-yr-old planted koa, and...

Fire-history reconstructions are based on tree-ring records that span the last few centuries and charcoal data from lake-sediment cores that extend back several thousand years. The two approaches have unique strengths and weaknesses in their ability to depict past fire events and fire regimes, and most comparisons of these datasets in western conifer forests have focused on sites characterized by high-severity crown fires. Tree-ring and charcoal data spanning the last 300 years in four watersheds in the montane forests of the Klamath Mountains provided an opportunity to compare the records...