Treesearch

Based on cross-dated increment cores, yearly diameters of trees were reconstructed for 21 laurels (Cordia alliodora) growing in a natural secondary forest on Gigante Peninsula, Panama. From this sample of dominant-codominant trees, ages were 14–35 years with an average of 25 years. Growth typically slowed at 7 years old, indicating effects of competition from closure of gaps in the canopy. Rate of growth in diameter was modeled using the Bertalanffy-Richards growth function. Four patterns of growth were detected, of which 57% were sigmoidal, 19% were convex, 10% were monomolecular, and 14%...

Since adoption of the Northwest Forest Plan (NWFP) in the early 1990s, there has been a fundamental shift in forest management practices on federal lands in western Oregon and Washington. Commodity driven clearcut regeneration harvests have given way to thinnings intended to enhance development of late-successional forest habitats and to conserve important aquatic and riparian ecosystems. Density Management in the 21st Century: West Side Story presents abstracts and peer reviewed papers from a regional conference highlighting more than twenty years of research related to forest thinning in...

Climate change is already affecting many fish and wildlife populations. Managing these populations requires an understanding of the nature, magnitude, and distribution of current and future climate impacts. Scientists and managers have at their disposal a wide array of models for projecting climate impacts that can be used to build such an understanding. Here, we provide a broad overview of the types of models available for forecasting the effects of climate change on key processes that affect fish and wildlife habitat (hydrology, fire, and vegetation), as well as on individual species...

Undebarked ponderosa pine chips were treated by hot water extraction to modify the chemical composition. In the treated pine (TP) , the mass was reduced by approximately 20%, and the extract was composed mainly of degradation products of hemicelluloses. Wood flour produced from TP and unextracted chips (untreated pine, UP) was blended with high-density polyethylene (HDPE) and polypropylene (PP) and was extruded into wood plastic composites (WPCs). Formulations for WPCs consisted of 58% pine, 32% plastic, and 10% other additives. WPC based on HDPE+TP and PP+TP absorbed 46-45% less water...

The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early and late-successional species differ in resistance to experimentally imposed soil drought. The microenvironment in early successional sites was warmer and drier than in mature forest. Nevertheless, successional groups did not...

Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: CurcuIionidae: Scolytinae), is among the primary causes of mature lodgepole pine, Pinus contorta variety latifolia mortality. Verbenone is the only antiaggregant semiochemical commercially available for reducing mountain pine beetle infestation of lodgepole pine. The success of verbenone treatments has varied greatly in previous studies because of differences in study duration, beetle population size, tree size, or other factors. To determine the ability of verbenone to protect lodgepole pine over long-term mountain pine...

Insects are ectotherms that cannot regulate their own temperature, and thus rely on and are at the disposal of the surrounding environment. In this study, long-term climatic data are used to stratify forested regions of Alaska into climatic zones based on temperature and precipitation. Temperature and precipitation are shown to be important ecological drivers in determining the distribution of aspen leaf miner (Phyllocnistis populiella Chambers) and the aspen (Populus tremuloides Michx.) host in the state of Alaska. Climatic regions based on temperatures and precipitation accounted for 83...

Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth.

Prescribed burning is used to reduce fuel loads and to return fire to its historic disturbance role in western forests. Managers need to know the effects of prescribed fire on tree growth. Growth of residual ponderosa pine (Pinus ponderosa Dougl. ex Laws.) was measured in an existing long-term study of the effects of season-of-prescribed burn in combination with a single or a repeated burn. Each of six previously thinned mixed-age stands in the Blue Mountains near Burns, Oregon, was subdivided into three experimental units, and one of three treatments was randomly assigned to each: fall...

Smart growth strategies of infill and compact growth in existing suburban cities will most likely not be sufficient to absorb a new US household growth in the future. To meet housing demands and preferences, master-planned communities will continue to be built in outlying exurban areas. However, little is known about the impacts these communities may have on the surrounding physical, built and social environment in the exurban landscape. In this paper, we provide a review of the literature of what is known about the drivers behind the development of master-planned communities and the...