Treesearch

A long-term study on the Fernow Experimental Forest (FEF) in West Virginia provided an opportunity to test for differences in the timber quality of trees harvested from three silvicultural practices (HarvestType): diameter-limit, patch cutting, and single-tree selection. The effects of HarvestType and site index (SI) over time on the harvested proportion of trees with grade 1 butt logs within a compartment were tested using a repeated-measures linear mixed model. HarvestType*Time was a significant interaction (P = 0.0018) and SI had a slight positive effect (P = 0.0036). When examining the...

Mastication is the process of chipping or shredding components of the tree canopy or above-ground vegetation to reduce the canopy, alter fire spread rates, and reduce crown fire potential. Mastication as a fuel treatment, either alone or in combination with prescribed fire, has been the subject of much research. This research has shown that modeling expected fire behavior in these fuels is challenging. Masticated materials from different ecosystems are unique and may react differently to fire. Therefore, there are no standard guidelines to help managers understand the potential fire...

Cogongrass (Imperata cylindrica (L.) Beauv.) is a warmseason perennial grass species found throughout tropical and sub-tropical regions of the world (Hubbard 1944). Native to Southeast Asia, cogongrass is an aggressive invasive plant that that has spread to all continents except Antarctica (MacDonald 2004) and is considered among the worst problematic weeds on a global scale (Holm et al. 1977). In the United States, it is naturalized in Virginia, North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, Texas, and Oregon (USDA Plants 2017). It was first accidentally...

Understanding the impacts of clear-cutting is critical to inform sustainable forest management associated with net primary productivity and nutrient availability over the long-term. Few studies have rigorously tested model simulations against field measurements which would provide more confidence in efforts to quantify logging impacts over the long-term. The biogeochemical model, PnET-BGC has been used to simulate forest production and stream chemistry at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. Previous versions of PnET-BGC could accurately simulate the longer-term...

Background: The main objective of this study was to examine the climatic sensitivity of the radial growth response of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the northern part of the species' native distribution in eastern North America. Methods: The test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in...

Eddy covariance methodologies have greatly improved our understanding of the forest carbon cycle, including controls over year-to-year variability in productivity (measured as net ecosystem productivity, NEP, where NEP is the difference between the mass of carbon fixed by photosynthesis and that lost by ecosystem respiration). However, establishing and maintaining eddy covariance towers requires sizeable financial and logistical investments. Tree-ring methods, which can produce annual estimates of tree biomass increment from individual trees, provide an alternative approach for assessing...

Despite decades of research, gaining a comprehensive understanding of carbon (C) cycling in forests remains a considerable challenge. Uncertainties stem from persistent methodological limitations and the difficulty of resolving top-down estimates of ecosystem C exchange with bottom-up measurements of individual pools and fluxes. To address this, we derived estimates and associated uncertainties of ecosystem C fluxes for a 100–125 year old mixed temperate forest stand at the Bartlett Experimental Forest, New Hampshire, USA, using three different approaches: (1) tower-based eddy covariance,...

While much research over the past 30 years has focused on the deleterious effects of excess N on forests and associated aquatic ecosystems, recent declines in atmospheric N deposition and unexplained declines in N export from these ecosystems have raised new concerns about N oligotrophication, limitations of forest productivity, and the capacity for forests to respond dynamically to disturbance and environmental change. Here we show multiple data streams from long-term ecological research at the Hubbard Brook Experimental Forest in New Hampshire, USA suggesting that N oligotrophication in...

Genetic resources have to be managed appropriately to mitigate the impact of climate change. For many wildland plants, conservation will require knowledge of the climatic factors affecting intraspecific genetic variation to minimize maladaptation. Knowledge of the interaction between traits and climate can focus management resources on vulnerable populations, provide guidance for seed transfer, and enhance fitness and resilience under changing climates. In this study, traits of big sagebrush (Artemisia tridentata) were examined among common gardens located in different climates. We focus...

Anomalous dark rings found in black cherry (Prunus serotina Ehrh.) sawlogs have been anecdotally related to defoliations from cherry scallop shell moth (CSSM) (Hydria prunivorata Ferguson). Using six timber harvest sites on the Allegheny National Forest and a thinning on the Kane Experimental Forest in northwestern Pennsylvania, we documented the occurrence of dark rings in the 1970s, 1980s, and 1990s, concurrent with historical CSSM defoliations. Thirty cross-sections sampled from six Allegheny National Forest sites showed that dark rings formed on 18 sections in the 1970s, 17 sections in...