Treesearch

The phenology of diameter-growth cessation in trees will likely play a key role in mediating species and ecosystem responses to climate change. A common expectation is that warming will delay cessation, but the environmental and genetic influences on this process are poorly understood. We modeled the effects of temperature, photoperiod, and seed-source climate on diameter-growth-cessation timing in coast Douglas-fir (an ecologically and economically vital tree) using high-frequency growth measurements across broad environmental gradients for a range of genotypes from different seed...

This volume presents findings on, and implications for, wildlife conservation in the tropical forests in Garo Hills of Meghalaya state in the North East India. A companion volume presented the findings on forest fragmentation due to practice of slash and burn agriculture in the region. Both of the volumes summarize work completed over more than a decade on characterizing conditions of tropical forests in the Garo Hills of western Meghalaya State of North East India. The work has led to innovations in use of remote sensing information and tools and to suggestions for designing a protected...

Epiphytic lichens are bioindicators of climate, air quality, and other forest conditions and may reveal how forests will respond to global changes in the U.S. Pacific States of Alaska, Washington, Oregon, and California. We explored climate indication with lichen communities surveyed by using both the USDA Forest Service Forest Inventory and Analysis (FIA) and Alaska Region (R10) methods. Across the Pacific States, lichen indicator species and ordination “climate scores” reflected associations between lichen community composition and climate. Indicator species are appealing targets for...

The Blue Mountains ecoregion (BME) extends from the Ochoco Mountains in central Oregon to Hells Canyon of the Snake River in extreme northeastern Oregon and adjacent Idaho, and then north to the deeply carved canyons and basalt rimrock of southeastern Washington (see fig. 1.1 in chapter 1). The BME consists of a series of mountain ranges occurring in a southwest to northeast orientation, allowing the BME to function ecologically and floristically as a transverse bridge between the Cascade Mountains province to the west, and the main portion of the middle Rocky Mountains province to the east.

Woodpeckers and other cavity-excavating birds worldwide are keystone species. These birds excavate their nests out of solid wood, and because their nests are often well protected against predators and the environment, other species use and compete for their old, vacant nests. The presence of cavity-excavating birds in forests has far-reaching effects on species richness and ecosystem health. Given the species’ importance, Teresa Lorenz, a research wildlife biologist with the U.S. Forest Service Pacific Northwest Research Station wanted to find out why cavity-excavating birds do not use...

Historically, oak forests and woodlands intergraded with southern boreal forest, temperate mesic forest, and grassland biomes, forming complex fire-mediated relationships in the Great Lakes region of Minnesota, Wisconsin, and Michigan, USA. Variability in fire recurrence intervals allowed oaks to mix with grasses or with mesic forest species in areas with high (2–10 yr) or moderate (several decades) fire frequencies, respectively. In the southern boreal forest, oak colonization was limited by cold climate. In recent decades former savannas have been largely converted to agricultural fields...

We report on the results of surveillance for the salamander chytrid fungus, Batrachochytrium salamandrivorans (Bsal). Two samples from archived DNA used in a previous chytrid study in Oregon were Bsal-positive, alerting us to the first potential finding of this pathogen in North America, infecting American bullfrogs and rough-skinned newts. To confirm the finding, several additional diagnostic tests were conducted, with results that did not definitively confirm our positive finding and our gene sequencing suggested our DNA had differences from the European Bsal fungus. Insufficient sample...

Key message Mature Coffea arabica leaves were more heat tolerant than expanding leaves, longer recovery time yielded more accurate thermotolerance assessments, and photochemistry was more heat sensitive than cell membranes. Abstract Given future climate predictions of increased heatwaves in the tropics, suitable habitat to grow ecologically, economically, and socially valuable Coffea arabica L. is threatened. Accurate assessments of high temperature tolerance or thermotolerance are critical for understanding C. arabica responses to increased temperature. Thermotolerance curves of C....

Given future climate predictions of increased temperature, and frequency and intensity of heat waves in the tropics, suitable habitat to grow ecologically, economically, and socially valuable Coffea arabica is severely threatened. We investigated how leaf age and heat stress duration impact recovery from heat stress in C. arabica. Treated plants were heated in a growth chamber at 49°C for 45 or 90 min. Physiological recovery was monitored in situ using gas exchange, chlorophyll fluorescence (the ratio of variable to maximum fluorescence, FV/FM), and leaf nonstructural carbohydrate (NSC) on...

To test tree growth-sensitivity to temperature under different ambient CO2 concentrations, we determined stem radial growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatial variation in temperature across the modern species distributional range. Paleo oaks were sampled from Northern Missouri, USA and compared to a pollen-based, high-resolution paleo temperature reconstruction from Northern Illinois, USA. Growth data were from 53 paleo bur oak log cross-sections collected in Missouri....