Treesearch

National Park Service policies stipulate that each park with vegetation capable of burning will prepare a fire management plan. Badlands National Park completed its fire management plan in 2004. Fossils are a principle resource of the park and the fire sensitivity of fossils is the focus of this study. The surface temperatures of fossil specimens and fire behavior characteristics were monitored in prescribed fires on the landscape and in laboratory burns to develop an understanding of the relationship between burning conditions and changes in fossil specimen properties. Under laboratory...

The United States and Canada have used concentration-based parameters for air quality standards for ozone effects on forests in North America. The European critical levels method for air quality standards uses an exposure-based parameter, a cumulative ozone concentration index with a threshold cutoff value. The critical levels method has not been used in North America, but efforts are now being initiated in the United States and Canada to use the critical loads concept for nitrogen and sulfur deposition to forest and aquatic ecosystems. It is expected that if this effort is successful, the...

Patagonia’s rangelands are similar to those in western United States in terms of climate, topography, and vegetation physiognomy. However, differences in environmental, economic, and societal values do exist between regions. We assessed the usefulness of C&I (Criteria and Indicators) developed in the United States for other countries, and identified indicators not included in the SRR (Sustainable Rangelands Roundtable) set that would be important for monitoring the sustainability of Patagonia’s rangelands. Most of SRR’s C&I were relevant to conditions in Patagonia (Argentina). Less than...

A stochastic precipitation-runoff modeling is used to estimate a cold and warm-seasons water yield from a ponderosa pine forested watershed in the north-central Arizona. The model consists of two parts namely, simulation of the temporal and spatial distribution of precipitation using a stochastic, event-based approach and estimation of water yield from the watershed using deterministic and spatially varied water balance technique. In the first part, a selected group of theoretical probability distribution functions are used to describe the probability distribution of the various precipitati...

The balance between photosynthesis and plant respiration in tropical forests may substantially affect the global carbon cycle. Woody tissue CO2 efflux is a major component of total plant respiration, but estimates of ecosystem-scale rates are uncertain because of poor sampling in the upper canopy and across landscapes. To overcome these problems, we used a portable scaffolding tower to measure woody tissue CO2 efflux from ground level to the canopy top across a range of sites of varying slope and soil phosphorus content in a primary tropical rain forest in Costa Rica. The objectives of...

Saltcedar (Tamarix spp.) is a major invasive weed found throughout the Western United States and Mexico. Introduced into North America in the 1800s, this shrub to small tree, now infests many riparian areas where it displaces native vegetation, increases fire hazards, uses extensive amounts of water, increases flooding during high water events and thus has caused extensive damage to urban, agricultural and natural areas. In 2001, scientists from the United States Department of Agriculture released a Chinese leaf beetle (Diorhabda elongata) into test areas in six states to initiate and...

Amphibians and reptiles (herpetofauna) play important roles within ecosystems. Similar to many birds and mammals, they are major consumers of terrestrial arthropods. However, amphibians and reptiles are more efficient at converting food into biomass and are a higher quality food source for predators. Recent declines in some herpetofaunal populations have stimulated a greater overall interest in the monitoring of these populations. Although studies have examined the use of exotic plant-invaded ecosystems by birds and mammals, few have focused on the herpetofaunal community. Specifically,...

This article describes a prototype modeling system for assessing forest management-related erosion at its source and predicting sediment transport from hillslopes to stream channels and through channel networks to a watershed outlet. We demonstrate that it is possible to develop a land management tool capable of accurately assessing the primary impacts of spatiotemporally varied forest management practices on sediment yield and delivery at hillslope to watershed scales in a single simulation. The modeling system consists of four components: (1) the TOpographic ParameteriZation (TOPAZ)...

We investigated the departure, transient movement, and local settlement stages of natal dispersal in a population of Northern Goshawks (Accipiter gentilis) on the Kaibab Plateau of northern Arizona. The study included 614 color-banded juveniles produced at 555 nests during 1991-2003, 89 of which were radio-marked during 1998-2001. Radio-marked juveniles initiated dispersal between 71 and 103 days posthatching, and spent between 33 and 66 days in the natal territory after fledging. Our best-fitting proportional hazards models predicted the timing of dispersal as a function of annual...

The key problem of conventional agriculture in the tropics and subtropics is the steady decline in soil fertility, which is closely correlated with the duration of soil use. The reason for this can be found primarily in the occurrence of soil erosion, the loss of organic matter, leaching of nutrients into deeper soil layers, and soil physical degradation associated with conventional tillage practices that leaves the soil bare and unprotected in times of heavy rainfall and heat (Derpsch and Moriya 1998). The result of soil degradation is not only that farm land has to go out of the productio...