Treesearch

Mountain pine beetles periodically infest pine forests in western North America, killing many or most overstory pine stems. The surviving secondary stand structure, along with recruited seedlings, will form the future canopy. Thus, even-aged pine stands become multiaged and multistoried. The species composition of affected stands will depend on the presence of nonpines and outbreak severity, among other factors, and can range from continued dominance by pines to hastened conversion to more shade-tolerant species. The loss of mature host trees results in reductions of ecosystem carbon...

The elevated levels of tree mortality attributed to mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) in western North American forests create forest management challenges. This investigation introduces the production of submicron or nanometer lignocellulose fibrils for value-added materials from the widely available resource represented by dead pines after an outbreak. Lodgepole pine (Pinus contorta Dougl. ex Loud.), trees from two different times since infestation and a noninfested live tree as a control were used for mechanical fibrillation. Fiber deconstruction down to the...

The magnitude and urgency of current mountain pine beetle outbreaks in the western United States and Canada have resulted in numerous studies of the dynamics and impacts of these insects in forested ecosystems. This paper reviews some of the aspects of the spatial dynamics and landscape ecology of this bark beetle. Landscape heterogeneity influences dispersal patterns in many ways, but little is known about these influences that can be used in management efforts, and the natural range of variability of this insect remains undefined. Short range spread is often determined by the active...

During its life cycle, the tree-killing mountain pine beetle Dendroctonus ponderosae Hopkins interacts with phoretic organisms such as mites, nematodes, fungi, and bacteria. The types of associations these organisms establish with the mountain pine beetle (MPB) vary from mutualistic to antagonistic. The most studied of these interactions are those between beetle and fungi. The least studied are interactions with bacteria, but these have received increased attention recently. Nematodes remain little studied. We reviewed the significant literature pertaining to MPB phoronts. A number of...

It is well documented in the scientific and popular literature that large-scale bark beetle outbreaks are occurring across many coniferous forests in the western United States. One of the major species exhibiting extensive eruptive populations resulting in high levels of tree mortality is the mountain pine beetle, Dendroctonus ponderosae (Hopkins) (Negron et al. 2008) (Figure 1). The literature on D. ponderosae is extensive and "navigating" through the many outlets in seeking information and summarizing it can be a daunting task. This special section of Forest Science contains 10 papers...

Mountain pine beetle, Dendroctonus ponderosae Hopkins, is a primary agent of forest disturbance in western North America. Episodic outbreaks occur at the convergence of favorable forest age and size class structure and climate patterns. Recent outbreaks have exceeded the historic range of variability of D. ponderosae-caused tree mortality affecting ecosystem goods and services at broad spatial scales. At the same time, significant advances have occurred in our understanding of the chemical ecology of D. ponderosae and in the development of semiochemical-based tools and tactics to protect...

Summary 1. Mismatches between species distributions and habitat suitability are predicted by niche theory and have important implications for forecasting how species may respond to environmental changes. Quantifying these mismatches is challenging, however, due to the high dimensionality of species niches and the large spatial and temporal variability in population dynamics. 2. Here, we explore how probabilistic assessments of habitat suitability based on demographic models may be used to better bridge niche theory and population dynamics. We use integral projection models (IPMs) to...

Summary 1. Hutchinsonian niche theory posits that organisms have fundamental abiotic resource requirements from which they are limited by competition. Organisms also have fundamental biotic requirements, such as mutualists, for which they also might compete. 2. We test this idea with a widespread ant–plant mutualism. Ant-mediated seed dispersal (myrmecochory) in eastern North America involves a few ant species that can effectively disperse the seeds of many plant species. This imbalance suggests that ant-dispersed plants (myrmecochores) might compete for ant dispersers. We hypothesized...

Decomposition of organic matter strongly influences ecosystem carbon storage1. In Earth-system models, climate is a predominant control on the decomposition rates of organic matter2, 3, 4, 5. This assumption is based on the mean response of decomposition to climate, yet there is a growing appreciation in other areas of global change science that projections based on mean responses can be irrelevant and misleading6, 7. We test whether climate controls on the decomposition rate of dead wood—a carbon stock estimated to represent 73 ± 6 Pg carbon globally8—are sensitive to the spatial scale...

This resource update provides an overview of forest resource attributes for Nebraska based on annual inventories conducted by the Forest Inventory and Analysis (FIA) Program of the Northern Research Station (NRS) of the U.S. Forest Service. The estimates presented in this update are based on field data collected in 2009-2013 with comparisons made to data collected from 2004-2008. These estimates, along with web-posted core tables, are updated annually. For more information, please refer to inventory citations on page 5 of this report.