Treesearch

Airborne measuremens of trace gases and particles in the smoke from a prescribed burn of forest products in the Los Angeles basin show significantly higher emissions of NOx, SO2, and particulate NO3 than do measurements in smokes from the burning of biomass in rural areas. It is postulated that the high emissions are due to the revolatilization of previously deposited pollutants. Implications for pollutant source inventories and the nuclear winter hypothesis are briefly discussed.

The feral goat (Capra hircus) is an alien herbivore that has wreaked havoc in island ecosystems, including the dry, rugged, and relatively inaccessible montane koa parkland on the islands of Maui and Hawai'i. The objective of the present work was to evaluate the ability of koa parkland on Maui to recover naturally from browsing damage if goats are eliminated. We studied recovery over 7 years by periodically determining percent ground cover, species composition, and woody plant abundance inside and outside a goat exclosure. Initially, plant cover did not differ inside and outside the...

Crown damage caused by gouty pitch midge (GPM) and its effects on tree growth were assessed in two 14-year-old ponderosa pine plantations, one on a shallow, infertile soil derived from serpentine and the other on a deeper, more fertile nonserpentine soil of marine parent material. Seed sources for each plantation were nearby indigenous stands on the same soils. Trees in both plantations had either viscid (resinous) or nonviscid surfaces on spring shoots. Light to moderate GPM damage was found in both plantations. Trees of both seed sources grew much faster in the nonserpentine than in the...

In their recent paper describing the distribution of genetic variation in black spruce (Picea mariana (Mill.) B.S.P.) on the island of Newfoundland, Yeh et el. (1986) concluded that a center of variability in west-central Newfoundland derived from ancestral populations that persisted on the island during the last (Wisconsin) glaciation. They attributed to Munns (1938) the "theory that part or all of such an area was ice-free during the Wisconsin glaciation." Munns's publication consists of tree distribution maps, long since superseded and not very accurate even when they were published;...

Growth responses of Eucalyptus saligna to nitrogen (N) and phosphorus (P) fertilizers were assessed in bioenergy plantations on abandoned sugarcane land in Hawaii. Fertilizers were applied three times (0, 6, and 15 months after planting) in a factorial design with four dosages each of N (0, 25, 50, and 75 g urea per tree) and P (0, 30, 60, and 90 g triple superphosphate per tree). Phosphorus and the N x P interaction had little effect on tree growth. Effects of N, however, were dramatic during the first year, and benefits were sustained through 6 years. Trees treated with 25 g urea were...

Tremendous species diversity, together with accelerating deforestation and land development, has been a formula for rampant extinction and community collapse in tropical forests. Conservationists have brought the crisis of tropical forests to the attention of the international community, showing that continued efforts are needed to conserve the biotic riches of these regions. The forests of temperate latitudes, although less in worldwide focus, also have urgent conservation needs, but of a somewhat different nature. As in tropical forests, biodiversity in temperate forests is high, and the...

Presented here are results of rooting studies using hedges established from juvenile seedlings of "blue" and "green" foliaged bishop pine (Pinus muricata D. Don) from Mendocino and Sonoma Counties, California. Rootability, averaged over all clones and all setting dates, was 88%. The average time for 50% of the cuttings to root was 6 months. In general, cuttings began to root rapidly in late winter/early spring. The time of year when cuttings were set determined how soon they began a phase of rapid rooting, with cuttings set in winter and early spring beginning faster than other setting...

The annual costs attributable to large fire suppression in three Forest Service Regions (1970-1981) were estimated as a function of fire perimeters using linear regression. Costs calculated on a per chain of perimeterbasis were highest for the Pacific Northwest Region, next highest for the Northern Region, and lowest for the Intermountain Region. Recent costs in real terms for the Intermountain and Pacific Northwest Regions are lower when adjusted for fire sizes, indicating that cost calculations based on pre-1976 data may overestimate current costs.

Between August 1983 and December 1985, 19 mountain lions were captured, radio equipped, and monitored daily within a portion of the North Kings deer herd range on the west slope of the central Sierra Nevada in California. The density of adult mountain lions was estimated to be one per 33.3 km²; that of adults and kittens together was estimated to be one per 20.9 km². Home-ranges averaged 265 km² for adult females and 350 km² for adult males. Home range overlap was high among females, among males, and between males and females. Some mountain lions migrated elevationally with the deer, but...

Two types of small (30-cm aperture) sheet metal sediment traps were developed to monitor onslope surface sediment transport. Traditionally, sediment traps and erosion pins have been used to measure the onslope movement of surficial soil material. While pins may be appropriate for documenting landscape denudation, traps are more suitable for monitoring downslope transport parallel to the ground surface. Previous investigations used large (3-m aperture) traps to measure sediment transport. However, large aperture traps are cumbersome and require excessive amounts of time and energy for...