Treesearch

An understanding of long-term growth dynamics is central to the development of sustainable uneven-aged silvicultural systems for northern hardwood forests in eastern North America. Of particular importance are quantitative assessments of the relationships between stocking control and long-term growth and quality development. This study examined these relationships in a long-term silviculture experiment established in northern hardwood stands in the Upper Peninsula of Michigan, USA. Stands were old growth at the onset of the experiment and were maintained at three residual stocking levels...

Considerable progress has been made in understanding the impacts of soil frost on carbon (C) and nitrogen (N) cycling, but the effects of soil frost on C and N fluxes during snowmelt remain poorly understood. We conducted a laboratory experiment to determine the effects of soil frost on C and N fluxes from forest floor soils during snowmelt. Soil cores were collected from a sugar maple (Acer saccharum)—American beech (Fagus grandifolia) and a red spruce (Picea rubens)—balsam fir (Abies balsamea) forest at the Hubbard Brook Experimental Forest in New Hampshire, U.S.A. Soils were...

Lodgepole pine is one of the most widely distributed conifers in North America, with a mixed-severity rather than stand-replacement fire regime throughout much of its range. These lodgepole pine forests are patchy and often two-aged. Fire exclusion can reduce two-aged lodgepole pine heterogeneity. This management guide summarizes the effects of thinning and prescribed burning treatments in an effort to restore twoaged lodgepole pine stands on the Tenderfoot Creek Experimental Forest, Montana. We report changes in tree density and fuel loading following thinning and prescribed burning....

Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed and natural elevation gradient studies at the Hubbard Brook Experimental Forest and in the surrounding region show surprising results demonstrating the effects of climate change on hydrologic variables (e.g., evapotranspiration, streamflow, soil moisture); the importance of changes in phenology on water, carbon, and nitrogen fluxes during critical seasonal transition periods; winter...

Heating any soil during a sufficiently intense wildfire or prescribed burn can alter it irreversibly, causing many significant, long-term biological, chemical, and hydrological effects. Given the climate-change-driven increasing probability of wildfires and the increasing use of prescribed burns by land managers, it is important to better understand the dynamics of the coupled heat and moisture transport in soil during these extreme heating events. Furthermore, improved understanding and modeling of heat and mass transport during extreme conditions should provide insights into the associate...

Ice storms are an important natural disturbance within forest ecosystems of the northeastern United States. Current models suggest that the frequency and severity of ice storms may increase in the coming decades in response to changes in climate. Because of the stochastic nature of ice storms and difficulties in predicting their occurrence, most past investigations of the ecological effects of ice storms across this region have been based on case studies following major storms. Here we report on a novel alternative approach where a glaze ice event was created experimentally under controlled...

Long-term hydrology and climate data from United States Forest Service Experimental Forests and Ranges (EFR) provide critical information on the interactions among climate, streamflow, and forest management practices. We examined the relationships among streamflow responses to climate variation and forest management using long-term data. Analysis of climate data from a subset of EFRs suggested an increase in air temperature over the past 20-30 years. Streamflow increased initially after cutting for all sites and cutting treatments, but the longer term responses vary considerably across...

Nutrient budgets for forested ecosystems have rarely included error analysis, in spite of the importance of uncertainty to interpretation and extrapolation of the results. Uncertainty derives from natural spatial and temporal variation and also from knowledge uncertainty in measurement and models. For example, when estimating forest biomass, researchers commonly report sampling uncertainty but rarely propagate the uncertainty in the allometric equations used to estimate tree biomass, much less the uncertainty in the selection of which allometric equations to use. Change over time may have...

Projected changes in climate for the northeastern USA over the next 100 years include a reduction in the depth and duration of the winter snowpack, which could affect soil temperatures and frost regimes. We conducted a snow-removal experiment in a northern hardwood forest at the Hubbard Brook Experimental Forest in central New Hampshire over 2 years to induce soil freezing and evaluate its effect on the abundance, richness, and diversity of soil arthropods during the growing season.

Evaluating the effectiveness and efficiency of fixed- and rotary-wing aircraft is a crucial component of strategic wildfire management and planning. In this manuscript, we focus on the economics of fire and aviation management within the US Forest Service. Substantial uncertainties challenge comprehensive analysis of airtanker use, prompting calls from federal oversight agencies for improved aerial firefighting data collection and analysis. Here, we explore the availability and sufficiency of agency aviation data to track airtanker use and cost trends, and to categorise airtanker use by...