Treesearch

Experiments were conducted wherein wood shavings and Ponderosa pine needles in quiescent air were subjected to a steady radiation heat flux from a planar ceramic burner. The internal temperature of these particles was measured using fine diameter (0.076mm diameter) type K thermocouples. A narrow angle radiometer was used to determine the emissive power generated by the burner. A model was developed to predict the steady-state temperature of a cylindrical particle with an imposed radiation heat flux under both quiescent air (buoyancy-induced cooling) and windy (forced convection cooling)...

We propose a fundamental geographic distribution for the wolverine (Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS classified satellite images representing persistent snow cover from 24 April to 15 May, which encompasses the end of the wolverine's reproductive denning period. To investigate the wolverine's spatial relationship with...

Whitebark pine is declining across much of its range in North America because of the combined effects of mountain pine beetle epidemics, fire exclusion policies, and widespread exotic blister rust infections. This management guide summarizes the extensive data collected at whitebark pine treatment sites for three periods: (1) pre-treatment, (2) 1 year post-treatment, and (3) 5 years post-treatment (one site has a 10 year post-treatment measurement). Study results are organized here so that managers can identify possible effects of a treatment at their own site by matching it to the most...

Climate is constantly changing, prompting natural and managed ecosystems to adjust. As a natural process, adaptation refers to the reactive changes that species and ecosystems make in response to environmental changes. With human intervention, adaptation refers to management actions and decisions that help ecological, social, and economic systems accommodate challenges imposed by climate change. Management actions can be developed to anticipate climate change and associated changes in natural disturbances such as fire and insects. Adaptation options for resource management may focus on the...

Climate change affects forests and grasslands in many ways. Changes in temperature and precipitation affect plant productivity as well as some species' habitat. Changes in key climate variables affect the length of the fire season and the seasonality of National Forest hydrological regimes. Also, invasive species tend to adapt to climate change more easily and increase extinction risks for native species.

Recent reports of rapid die-off of aspen (Populus tremuloides), coupled with vigorous debate over longterm reduction of aspen cover in western North America, has prompted considerable research given the importance of this forest type for economic and non-economic interests. Despite this interest, indicators of aspen conditions are poorly understood, and there is a lack of systematic monitoring of stable aspen landscapes. Stable aspen are defined here as being predominantly aspen overstorey (>80% basal area) with little or no conifer regeneration. We examined a putative stable aspen...

Tamarix ramosissima is a naturalized, nonnative plant species which has become widespread along riparian corridors throughout the western United States. We test the hypothesis that the distribution and success of Tamarix result from human modification of river-flow regimes. We conducted a natural experiment in eight ecoregions in arid and semiarid portions of the western United States, measuring Tamarix and native Populus recruitment and abundance at 64 sites along 13 perennial rivers spanning a range of altered flow regimes. We quantified biologically relevant attributes of flow alteration...

Spatially and temporally explicit knowledge of biomass dynamics at broad scales is critical to understanding how forest disturbance and regrowth processes influence carbon dynamics. We modeled live, aboveground tree biomass using Forest Inventory and Analysis (FIA) field data and applied the models to 20+ year time-series of Landsat satellite imagery to derive trajectories of aboveground forest biomass for study locations in Arizona and Minnesota. We compared three statistical techniques (Reduced Major Axis regression, Gradient Nearest Neighbor imputation, and Random Forests regression...

Forests are extremely complex systems that respond to an overwhelming number of biological and environmental factors, which can act singularly and in concert with each other, as exemplified by Puettmann et al. [1]. The complexity of forest systems presents an enormous challenge for forest researchers who try to deepen their understanding of the structure and function of these systems, and for forest managers who try to deploy practices that emulate natural processes. This paper addresses key issues in forest research and management and is divided into three sections: (1) disturbance, (2)...

Here we are again in a new year and it is time to reflect on our accomplishments and progress in 2009. Last year was marked with exciting advances in our science discovery, applications, and integration. Those advances were attained almost entirely with the aid of our partners and stakeholders. We continue to focus on communicating our science findings to land managers and policy makers to help them make informed decisions that will lead to the long-term sustainability of our forests, ranges, and grasslands.