Treesearch

The present study examines the manner in which several whole-tree water transport properties scale with species specific variation in sapwood water storage capacity. The hypothesis that constraints on relationships between sapwood capacitance and other water relations characteristics lead to predictable scaling relationships between intrinsic capacitance and whole-tree behavior was investigated. Samples of sapwood from four tropical forest canopy tree species selected to represent a range of wood density, tree size and architecture, and taxonomic diversity were used to generate moisture...

The Moderate Resolution Imaging Radiometer (MODIS) is the primary instrument in the NASA Earth Observing System for monitoring the seasonality of global terrestrial vegetation. Estimates of 8-day mean daily gross primary production (GPP) at the 1 km spatial resolution are now operationally produced by the MODIS Land Science Team for the global terrestrial surface using a production efficiency approach. In this study, the 2001 MODIS GPP product was compared with scaled GPP estimates (25 km2) based on ground measurements at two forested sites. The ground-based GPP scaling approach relied on...

WestPro is an add-in program designed to work with Microsoft Excel to simulate the growth of uneven-aged Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Pacific Northwest region of the United States. Given the initial stand state, defined as the number of softwood and hardwood trees per acre by diameter class, WestPro predicts the future stand state for each year of a predetermined time horizon. Management regimes are defined by a target stand distribution and a cutting cycle. Performance indicators include diversity of tree size and species, timber yield, and net present...

I examined the distributions of eight Physconia species in northern and central California: Physconia americana, P. californica, P. enteroxantha, P. fallax, P. isidiigera, P. isidiomuscigena, P. leucoleiptes, and P. perisidiosa. Distributions are based upon lichen community data collected for the Forest Inventory and Analysis Program in over 200 permanent plots. Physconia californica was not found while P. leucoleiptes was infrequent across the landscape, occurring sporadically around the periphery of the Central Valley. Physconia isidiomuscigena occurred only once in the study plots,...

Forest composition and structure on the eastern slope of the Cascade Mountains have been influenced by decades of fire exclusion. Multilayered canopies and high numbers of shade-tolerant true fir trees interact with western spruce budworm to alter forest structure and to affect potential fire behavior and effects. We compared measurements taken in 1992 (early budworm outbreak) and 2000 (late budworm outbreak) from 21 permanent plots located in a late successional reserve south of Mt. Adams in Washington. Canopy closure decreased significantly, from a mean of 78% in 1992 to 43% in 2000, but the...

Ecology, economy, and demography interact to affect forest management objectives. In the temperate rainforests of northwestern North America (Franklin and Halpern 1988), the outcome of this interaction for most of the 20th century was a management emphasis on wood production (Curtis et al. 1998, Haynes et al. 2003). Because of production efficiencies, even-aged, clearcut systems favoring harvest and regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) dominated regional silvicultural practices for decades (Tesch 1995, Curtis et al. 1998) (see Appendix 1 for all common and...

Between 1977 and 1997, 4000 ha were burned to promote regeneration of tree and shrub species used for browse by moose (Alces alces) in the Kenai Mountains. Species composition was documented along burned and unburned transects at 17 prescribed burn sites. Relationships among initial vegetation composition, physical site characteristics, browse species abundance, and competitive herbaceous vegetation were examined to determine controls on browse species regeneration after prescribed burning. Browse species abundance after burning was inversely related to Calamagrostis canadensis Michx....

Why manage for wildlife in U.S. forests? American society demands it. Which species should be favored? The social and cultural value of individual species continue to evolve. Large changes have taken place in less than 40 years; Kimmins (2002) states that changes in societal values have produced “future shock” in the forestry profession, with foresters and their institutions unable to adapt. Public demand for wildlife conservation has resulted in a long chain of legislation governing federal lands and supporting state and private wildlife conservation efforts (Hunter 1990). Nevertheless,...

Debris flows have typically been viewed as two-phase mixtures of sediment and water, but in forested mountain landscapes, wood can represent a sizable fraction of total flow volume. The effects of this third phase on flow behavior are poorly understood. To evaluate whether wood can have a significant effect on debris flow runout in small mountainous watersheds, we used a landscape-scale model combining empirical, stochastic, and physical submodels of storms, fires, forest growth, tree fall, wood decay, soil production and diffusion, landslide initiation, debris flow runout, and fluvial...

To assess values of air quality and visibility at risk from wildland fire in the United States, we generated a 40-year database that includes twice daily values of wind, mixing height, and a ventilation index that is the product of windspeed and mixing height. The database provides the first nationally consistent map of surface wind and ventilation index. In addition, it is the longest climate record of mixing height in the country. We built the database into an interactive ventilation climate information system that allows users to assess risk based on frequency patterns of poor, marginal,...