Treesearch

To deal with nonpoint sources of pollution, such as stream sediment produced by erosion from forest management operations, regulations require land managers to reduce onsite erosion to keep the amount of sediment discharged from each project area within acceptable limits. Activities developed to meet these regulations are sometimes referred to as best management practices (BMPs). BMPs are designed to reduce pollutant discharge from a single project but may not solve the larger problem concerning the cumulative effect of multiple projects

Abstract - Salmonid embryos depend on the adequate flow of oxygenated water to survive and interstitial passageways to emerge from the gravel bed. Spawning gravels are initially cleaned by the spawning female, but sediment transported during subsequent high-runoff events can nfiltrate the porous substrate. In many gravel-bed channels used for spawning, most of the infiltrating sediment consists of sand and fine gravel that fall by the force of gravity through the framework of bed particles once the sediment enters the streambed. The sediment comes to rest on the tops of large particles or...

The fraction of pool volume filled with fine sediment (usually fine sand to medium gravel) can be a useful index of the sediment supply and substrate habitat of gravel-bed channels. It can be used to evaluate and monitor channel condition and to detect and evaluate sediment sources. This fraction (V*) is the ratio of fine-sediment volume to pool water volume plus fine-sediment volume. These volumes are computed for the residual portion of the pool that lies below the elevation of the downstream riffle crest. Fine-sediment thickness is measured by driving a graduated metal probe into a...

Because Townsend's chipmunks (Tomias townsendii) may be important in maintaining natural ecosystem processes in forests in the central Oregon Cascade Range, we compared their population characteristics in young second-growth and old-growth forests. We live-trapped Townsend's chipmunks in 5 young (30-60 yr old) second-growth and 5 old-growth (>400 yr old) Douglas-fir (Pseudotsuga menziesii) stands during spring and autumn 1987-90 in western Oregon. We tested the null hypothesis of no difference in characteristics of chipmunk populations in these 2 stand age-classes. Densities ranged from...

The response of a channel with a topography and modeled bed material size typical of gravel bed rivers to reductions in sediment supply was investigated in a laboratory flume filled and fed with a sand-gravel mixture. After a series of quasi-stationary alternate bars were formed under equilibrium sediment transport, feed rate was reduced in two steps to one third and one tenth the initial rate as discharge was held constant. The primary response following both reductions was an increase in bed surface particle size as a corridor of intensive bed load transport contracted and local transport...

At the end of the workshop, I led a lightly structured and informal discussion concerning methods of continuing and improving communications and cooperation among workshop participants. The group specifically ad-dressed three areas: maintaining informal one-on-one direct contacts, improving the use of the ADAP computer system for mail, and the desirability of starting an informal newsletter about agroforestry activities in the Pacific. In addition, the group briefly discussed opportunities for cooperative studies.

Agroforestry is an important land-use in the Commonwealth of the Northern Marianas (CNMI) and provides many benefits. Various agencies are involved in forestry and agroforestry, and their programs are summarized in this paper. Major issues involving agroforestry in the CNMI are also discussed.

Agroforestry was an important land use in Palau, located in the western Caroline Islands. However, as a result of land restrictions and concentration on cash crops, the incorporation of trees in agriculture has declined.

Agroforestry exists in American Samoa as a system where indigenous trees and natural vegetation used for food, fuelwood, crafts and medicine are incorporated with traditional staple crops and livestock on a set piece of land, usually a mountainous slope. Most agroforests are taro-based (Colocasia esculenta). While nutritional, cultural, social, economic and ecological benefits are realized from the agroforest, sufficient quantitative and qualitative documentation and widespread knowledge of the importance of agroforestry is lacking. Other problems include a shift toward monocropping, the...

Abstract. We modeled tree mortality occurring two years following wildfire in Pinus ponderosa forests using data from 1275 trees in 25 stands burned during the 1987 Stanislaus Complex fires. We used logistic regression analysis to develop models relating the probability of wildfire-induced mortality with tree size and fire severity for Pinus ponderosa, Calocedrus decurrens, Quercus chrysolepis, and Q. kelloggii. One set of models predicts mortality probability as a function of DBH and height of stem-bark char, a second set of models uses relative char height (height of stem-bark char as a...