Treesearch

We compare how socioeconomic factors, physical landscape, profit uncertainty, and local land use policies have affected land development on the east and west sides of the Cascade Range in Oregon, Washington, and California. It is found that the west side has more actively planned and regulated land use than the east side. Consequently, the more intense land use regulations on the west side have reduced more land development than on the east side. Risks associated with alternative land uses as well as profits were important in land development decisions of both sides.

Oregon's land-use planning program is often cited as an exemplary approach to forest and farmland conservation, but analyses of its effectiveness are limited. This article examines Oregon's land-use planning program using detailed spatial data describing building densities in western Oregon. An empirical model describes changes in building densities on forest and agricultural lands from 1974 to 1994, as a function of a gravity index of land's commuting distance to cities of various sizes, topographic characteristics, and zoning adopted under Oregon's land-use planning program. The effective...

Wildfire suppression expenditures on national forest land have increased over the last 35 years, exceeding US $l billion in 2000 and 2002. These increases in expenditure have been attributed, in part, to a century of aggressive wildfire suppression, resulting in a buildup of fuel on the nation's forests. The efficiency of the current incentive structure faced by Forest Service fire managers is analyzed. An alternative incentive structure is presented that encourages fire managers, as they work to limit wildfire damages, to contain costs and consider the beneficial effects of wildfire.

As the U.S. population grows, many forestry professionals are thinking more about forestland development. Although forest policy debates often focus on whether to manage public forestlands for timber, ecological, or recreation purposes, almost three-fifths of the nation's forests are privately owned. While public forestlands will be with us for the foreseeable future, private forestlands have the potential to be lost to developed uses. Nationally, almost one million acres of forestland were lost to development annually from 1992 to 1997. Another 26 million acres could be lost by 2030.

Can a tree-specific mortality model elicit expected forest stand density dynamics without imposing stand-level constraints such as Reineke's maximum stand density index (SDI,) or the -312 power law of self-thinning? We examine this emergent properties question using the Austrian stand simulator PROGNAUS. This simulator was chosen specifically because it does not use stand density constraints to determine individual tree mortality rates. In addition, it is based on a probability sample of the population that includes the span of the data being used to test the hypothesis. Initial conditions...

Herbivory by wild and domestic ungulates can strongly influence vegetation composition and productivity in forest and range ecosystems. However, the role of ungulates as contributors to the establishment and spread of non-native invasive plants is not well known. Ungulates spread seeds through endozoochory (passing through an animal's digestive tract) or epizoochory (attached to an animal's body); hence, animal-mediated spread of invasive plants is a common phenomenon. Manipulative experiments of ungulate grazing effects on nonnative plant introduction, establishment, and spread are...

A study of the effects of season of prescribed burn on tree mortality was established in mixed-age ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at the south end of the Blue Mountains near Burns, Oregon. Each of six previously thinned stands was subdivided into three experimental units and one of three treatments was randomly assigned to each: fall 1997 burn, spring 1998 burn, and no burning (control). Bums were conducted as operational prescribed burns. Trees within six 0.2-ha circular plots on each experimental unit were observed for four post-burn growing seasons to determine fire...

We estimated the historical range of variability (HRV) of forest landscape structure under natural disturbance regimes at the scale of a physiographic province (Oregon Coast Range, 2 million ha) and evaluated the similarity to HRV of current and future landscapes under alternative management scenarios. We used a stochastic fire simulation model to simulate presettlement landscapes and quantified the HRV of landscape structure using multivariate analysis of landscape metrics. We examined two alternative policy scenarios simulated by two spatially explicit simulation models: (1) current...

Astragalus lentiginosus is a polymorphic species that occurs in geologically young habitats and whose varietal circumscription implies active morphological and genetic differentiation. In this preliminary study, we evaluate the potential of amplified fragment length polymorphism (AFLP) markers to resolve infraspecific taxa in three varieties of Astragalus lentiginosus. Distance-based principle coordinate and neighbor-joining analyses result in clustering of individuals that is congruent with population origin and varietal circumscription. Analysis of molecular variance of two Oregon...

Primary production by plants requires the loss of substantial quantities of water when the stomata are open for carbon assimilation. The delivery of that water to the leaves occurs through the xylem. The structure, condition, and quantity of the xylem control not only the transport efficiency but also the release of water from storage. For example, if there is high resistance to water flow in the stem, then less water is available to the leaves, so less primary production can occur. High resistance can result from wood material with low conductivity, from having only a small amount of...