Treesearch

Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae), an invasive phloem-feeding insect native to Asia, threatens at least 16 North American ash (Fraxinus) species and has killed hundreds of millions of ash trees in landscapes and forests. We conducted laboratory bioassays to assess the relative efficacy of systemic insecticides to control emerald ash borer larvae in winter 2009 and 2010. Second- and third-instar larvae were reared on artificial diet treated with varying doses of emamectin benzoate (TREE-age, Arborjet, Inc., Woburn, MA), imidacloprid (Imicide, J. J...

Fire is a prevalent feature of many landscapes and has numerous and complex effects on geological, hydrological, ecological, and economic systems. In some regions, the frequency and intensity of wildfire have increased in recent years and are projected to escalate with predicted climatic and landuse changes. In addition, prescribed burns continue to be used in many parts of the world to clear vegetation for development projects, encourage desired vegetation, and reduce fuel loads. Given the prevalence of fire on the landscape, authors of papers in this special series examine the complexitie...

Mountain pine beetle (Dendroctonus ponderosae) is an important disturbance agent in Pinus ecosystems of western North America, historically causing significant tree mortality. Most recorded outbreaks have occurred in mid elevation lodgepole pine (Pinus contorta). In warm years, tree mortality also occurs at higher elevations in mixed species stands.

Mountain pine beetle, Dendroctonus ponderosae Hopkins, is the most significant mortality agent in pine forests of western North America. Silvicultural treatments that reduce the number of susceptible host trees, alter age and size class distributions, and diversify species composition are considered viable, long-term options for reducing stand susceptibility to mountain pine beetle-caused tree mortality. Short-term efficacy of thinning treatments has been evaluated, but long-term efficacy has not. We evaluated mountain pine beetle-caused lodgepole pine mortality in 2008, ~28 years after...

In this paper, we describe our application of Ostrom et al.'s ADICO syntax, a grammatical tool based in the Institutional Analysis and Development framework, to a study of ecological restoration decision making in the Chicago Wilderness region. As this method has only been used to look at written policy and/or extractive natural resource management systems, our application is novel in context (a value-adding environmental management action), data type (in-depth, qualitative interviews, and participant observation), and extent of institutional statement extraction (we extract rules, as well...

Early applications of wilderness economic research demonstrated that the values of natural amenities and commodities produced from natural areas could be measured in commensurate terms. To the surprise of many, the economic values of wilderness protection often exceeded the potential commercial values that might result from resource extraction. Here, the concepts and tools used in the economic analysis of wilderness are described, and the wilderness economic literature is reviewed with a focus on understanding trends in use, value, and economic impacts. Although our review suggests that...

Seed transfer guidelines and zones are used to manage the movement of plant materials, but by the end of the century many landscapes across the globe will have climates that are incompatible with current vegetation. The mismatch in rates between climate change and plant migration and adaptation will pose significant challenges for natural resource managers, especially when scientific information often lags behind the demand for management actions. We developed a bibliography to reflect the growing interest in assisted migration, the intentional movement of plant materials in response to...

We detect transition to agropastoral land use in a mountain landscape by radiocarbon dating physical signatures (sedimentation rates, charcoal concentrations, magnetic susceptibility) of conversion from native forest to pasture contained within colluvial stratigraphic sections. Focus is on two study sites located on toeslopes directly beneath zero-order hollows draining several hectares in the commune of Larrau (Pyr
en
ees Atlantiques, France) along the international drainage divide of the western Pyrenees. Sample sites maximize likelihood of spatially and temporally uniform slopewash...

An attempt was made to model diameter distributions of aspen (Populus spp) stands. The aspen (1,020,150 acres) cover type has the greatest acreage on DNR lands and it contains a variety of hardwood and softwood species. Aspen is a valuable pulpwood species, annually comprising around 50 percent of total timber harvest on DNR lands. Modeling distributions of this cover type has been minimal; stands often contain a variety of tree sizes and species, making modeling difficult, particularly given a disproportionate amount of smaller trees. For this analysis, a three-parameter Weibull-based...

For Minnesota, the only data available to conduct regional or state-wide level assessments across all ownerships is the Forest Inventory and Analysis Program (FIA). Some of the many alternatives available to estimate regional changes in standing volume are referred to here as 1.) FIA alternative, 2.) a commonly applied growth and yield system referred to as Walters and Ek, 3.) a calibrated Walters and Ek alternative, 4.) a different calibrated Walters and Ek alternative, and 5.) Forest Vegetation Simulator (FVS) estimates. The purpose of this study is to quantify the ability of these...