Treesearch

This article describes a series of fundamental analyses designed to test and compare the utility of various MODIS data and products for detecting land cover change over a large area of the tropics. The approach for estimating proportional forest cover change as a continuous variable was based on a reduced major axis regression model. The model relates multispectral and multi-temporal MODIS data, transformed to optimize the spectral detection of vegetation changes, to reference change data sets derived from a Landsat data record for several study sites across the Central American region....

J. M. Vidal's recent reexaminatlon of the holotype of Arcangeliella borziana Cavara, the type species of that genus, revealed that it has been misinterpreted by various authors in the past. Vidal synonymised the genus Zelleromyces with Arcangeliella and transferred all Zelleromyces spp. to Arcangeliella except for two Australian species, Z. claridgei and Z. corkii. We complete his transfers here with· the new combinations Arcangeliella claridgei and A. corkii.

Cool summertime stream temperature is an important component of high-quality aquatic habitat in Oregon coastal streams. Within the Oregon Coast Range, small headwater streams make up a majority of the stream network, yet little information is available on temperature patterns and the longitudinal variability for these streams. In this paper we describe preharvest spatial and temporal patterns in summer stream temperature for small streams of the Oregon Coast Range in forests managed for timber production. We also explore relationships between stream and riparian attributes and observed...

1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2 to 1.0 km-2). 2. Browsing frequency was much greater in areas with high moose densities. The combined browsing pressure (percentage of annual browse production consumed by herbivores) of moose (Alces alces) and snowshoe hares (Lepus americanus) on forage species was over fivefold...

Understanding how the concentration and chemical quality of dissolved organic matter (DOM) varies in soils is critical because DOM influences an array of biological, chemical, and physical processes. We used PARAFAC modeling of excitation-emission fluorescence spectroscopy, specific UV absorbance (SUVA254) and biodegradable dissolved organic carbon (BDOC) incubations to investigate the chemical quality of DOM in soil water collected from 25 cm piezometers in four wetland and forest soils: bog, forested wetland, fen, and upland forest. There were significant differences in soil solution...

Thinking Like a Manager is a unique book that offers students and wildlife professionals a fresh format for considering a. complex array of themes associated with the contemporary wildlife management. The title refers to Aldo Leopold's classic essay, Thinking Like a Mountain, which promotes the integration of ecological and sociocultural processes in natural resource decisions. Thinking Like a Manager assumes the form of a fictional novel featuring six wildlife managers stranded on a remote beach. While waiting for the fog to lift, the characters draw from their experiences to discuss the...

Climate change, increased wildland fuels, and residential development patterns in fire-prone areas all combine to make wildfire risk mitigation an important public policy issue. One approach to wildfire risk mitigation is to encourage homeowners to use fire-resistant building materials and to create defensible spaces around their homes. We develop a theoretical model of interdependent household wildfire risk and mathematically introduce two new concepts of the benefits accruing from hazard mitigation: direct and spillover (indirect) damage averted. We explore how Firewise communities can...

Scientists and policymakers have long recognized the role that forests can play in countering the atmospheric buildup of carbon dioxide (C02), a greenhouse gas (GHG). In the United States, terrestrial carbon sequestration in private and public forests offsets approximately 11 percent of all GHG emissions from all sectors of the economy annually. Although much of the attention on forest carbon sequestration strategy in the United States has been on the role of private lands, public forests in the United States represent approximately 20 percent of the U.S. timberland area and also hold a...

Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but they likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height owing to path-length resistance and gravity. We used morphological measurements to estimate the hydraulic properties of the bordered pits between tracheids in Douglas-fir trees along a height gradient of 85 m. With increasing height, the xylem...

Sulfur cinquefoil is an exotic, perennial forb that invades a wide range of ecosystems in western North America. It forms dense populations and often threatens native plant species and communities. In this study, we address the following questions: (1) what herbicides, rates, and application times are most effective at reducing sulfur cinquefoil abundance while having the least impact on native plants and (2) does postherbicide seeding with native grass species increase native plant abundance? In 2002, we experimentally examined the effects of five herbicides (dicamba + 2,4~D; metsulfuron-m...