Treesearch

Although studies of pheromone production in the southern pine beetle (Dendroctonus frontalis) extend back to the dawn of chemical ecology, it is only recently that instrumentation has become sufficiently sensitive to measure pheromone production of individual beetles. Now, recent studies have revealed surprisingly high variation among individuals in their pheromone production. This seems paradoxical because pheromone signals in tree-killing bark beetles are apparently linked to fitness and have high heritability.

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae) (MPB), is widely distributed across western North America spanning 25 degrees latitude and more than 2,500 m elevation. In a common garden experiment, Bentz and others (2001) observed that MPB populations from a southern location required significantly more time to develop than individuals from a population in the northern part of the range, although both populations exhibited univoltinism. Adults from the southern population were also significantly larger, even when reared in a common host...

Spruce beetle, Dendroctonus rufipennis (Kirby), is one of the most broadly distributed bark beetles in North America, extending from Alaska to Newfoundland, south to Arizona. It colonizes most species of spruce within its range. Usually it is associated with highly stressed or killed trees, but under certain conditions undergoes landscape level eruptions that kill millions of trees (Werner and others 1977), regardless of their physiological condition (Wallin and Raffa 2004). Populations may be semivoltine or univoltine, depending on temperature (Hansen and others 2001). Spruce beetles show...

In northern areas of their expanded range, information on Merriam's turkeys (Meleagris gallopavo merriami) is lacking, specifically pertaining to wintering behavior and factors associated with winter habitat selection. Forest managers need detailed quantification of the effects of logging and other management practices on wintering habitats needed by Wild Turkeys and other wildlife. Therefore, we examined winter habitat selection patterns within ponderosa pine (Pinus ponderosa) forests and determined factors associated with use of farmsteads by Merriam's turkeys in the southern Black...

These proceedings provide a synopsis of the Third Workshop on Genetics of Bark Beetles and Association Microorganisms, which was held May 20-2, 2006 in Asheville, NC. Twenty- five participants from five countries attended the meeting. The proceedings are structured into four parts: Phylogenetics of Bark Beetles, Population Genetics of Bark Beetles, Bark Beetle Gene Structure and Function, and Genetics of Symbionts, Natural Enemies, and Hosts. The abstracts give a snapshot of our current understanding of the genetics of bark beetles and associated microorganisms.

The Forest Inventory and Analysis (FIA) program measures a number of chemical and physical properties of soils to address specific questions about forest soil quality or health. We developed a new index of forest soil health, the soil quality index (SQI), that integrates 19 measured physical and chemical properties of forest soils into a single number that serves as the soil's "vital sign" of overall soil quality. Regional and soil depth differences in SQI values due to differences in soil properties were observed. The SQI is a new tool for establishing baselines and detecting forest...

In this study, we report evidence that temperature plays a key role in determining the relative abundance of two mutualistic fungi associated with an economically and ecologically important bark beetle, Dendroctonus ponderosae. The symbiotic fungi possess different optimal temperature ranges. These differences determine which fungus is vectored by dispersing host beetles as temperatures fluctuate over a season. Grosmannia clavigera is the predominant fungus carried by dispersing beetles during cool periods but decreases in prevalence as daily maximum temperatures approach 25ºC, and becomes...

Data from 139 research sites throughout the Inland Northwest were analyzed for effects of ash cap on site productivity, nutrient availability and fertilization response. Stand productivity and nitrogen (N) fertilizer response were greater on sites with ash cap than on sites without. Where ash was present, depth of ash had no effect on site productivity or N fertilizer response. Site productivity increased with increasing potentially available soil water. Potentially available soil water, in turn, increased with increasing ash depth. Decreasing availability of magnesium (Mg) and calcium...

This paper presents empirical evidence that helps to understand how some visitors develop relationships with Rocky Mountain National Park in Colorado. The paper describes relationship to place as the active construction and accumulation of meaning, which involves both physical and social interactions over time. The discussion is organized around three themes evident in the data and the literature that describe, in part, how relationships to place develop: (a) time and past experience allow place meanings to accumulate, (b) social interactions with companions, and (c) physical interactions...

We developed and evaluated an individual-tree height growth model for Douglas-fir [Pseudotsuga menziesii (Mirbel) Franco] in the Inland Northwest United States. The model predicts growth for all tree sizes continuously, rather than requiring a transition between independent models for juvenile and mature growth phases. The model predicts the effects of overstory and understory vegetative competition on height growth. Our model requires attained height rather than tree age as a predictor variable, thereby avoiding the problems of site index. Site effects are introduced as a function of...