Treesearch

Mounting concerns about global climate change have increased interest in the potential to use common forest management practices, such as forest density management with thinning, in climate change mitigation and adaptation efforts. Long-term effects of forest density management on total aboveground C are not well understood, especially for precommercial thinning (PCT) implemented very early in stand development. To assess the climate change mitigation potential of PCT, as well as tradeoffs with climate change adaptation, we examined total aboveground C stores in a 54-year-old western larch...

Classic regeneration cuttings retaining trees at harvest (shelterwood with reserves, group selection) can be analyzed as analogs of variable-retention harvesting. A 1974 silvicultural experiment in the northern Rocky Mountains was analyzed at 38 years to evaluate the long-term effects of retention harvests on stand development, with a focus on both regeneration and retention tree responses. The postharvest understory treatments (understory removed and broadcast burned) effects were also evaluated. Results indicate that overstory retention results in relatively long-term regeneration growth...

Hand-constructed piles in eastern Washington and north-central New Mexico were weighed periodically between October 2011 and June 2015 to develop decay-rate constants that are useful for estimating the rate of piled biomass loss over time. Decay-rate constants (k) were determined by fitting negative exponential curves to time series of pile weight for each site. Piles at the Washington site (k = 0.027/year) decomposed significantly more slowly than piles at the New Mexico site (k = 0.064/year). Significant differences in k for each site may be a function of a between-site variation in pile...

Rocky Mountain forests are highly important for their part in carbon cycling and carbon storage as well as ecosystem services such as water retention and storage and recreational values. These forests are shaped by complex interactions among vegetation, climate, and disturbances. Thus, climate change and shifting disturbances may lead to significant changes in species composition and biomass. Individual tree-based modeling allows various climate change scenarios and their effects on forest dynamics to be tested. We use an updated individual-based gap model, the University of Virginia...

As light detection and ranging (LiDAR) technology advances, it has become common for datasets to be acquired at a point density high enough to capture structural information from individual trees. To process these data, an automatic method of isolating individual trees from a LiDAR point cloud is required. Traditional methods for segmenting trees attempt to isolate prominent tree crowns from a canopy height model. We here introduce a novel segmentation method, layer stacking, which slices the entire forest point cloud at 1-m height intervals and isolates trees in each layer. Merging the...

The degraded stand pictured in this 1955 USDA Forest Service photograph from Maine was dominated by balsam fir (Abies balsamea), red maple (Acer rubrum), paper birch (Betula papyrifera), and American beech (Fagus grandifolia). Stands such as these were typical of second-growth, lowland spruce–fir (Picea–Abies) forests in the Northeast following repeated high grading in the 1800s and early 1900s (Judd 1997). In light of concerns about the sustainability of the eastern spruce–fir cover type, the Forest Service began researching these forests in 1926 at the 1,863-acre Gale River Experimental...

Climate of the northern hardwood forests of North America will become significantly warmer in the coming decades. Associated increases in soil temperature, decreases in water availability and changes in winter snow pack and soil frost are likely to affect soil carbon (C) and nitrogen (N) cycling. Most studies of the effects of climate change on soil function have focused on the upper-organic part of the soil profile (e.g., forest floor), and little is known about effects on deeper mineral soil horizons. We exploited an elevation/orientation gradient at the Hubbard Brook Experimental Forest...

Despite growing interest in management strategies for climate change adaptation, there are few methods for assessing the ability of stands to endure or adapt to projected future climates. We developed a means for assigning climate "Compatibility" and "Adaptability" scores to stands for assessing the suitability of tree species for projected climate scenarios. We used these scores to determine whether mixed hardwood-softwood stands or "mixedwoods" were better suited to projected future climates than pure hardwood or pure softwood stands. We also examined the quantity of aboveground carbon...

Precommercial thinning (PCT) is used to increase tree size and shorten harvest rotation time. Short-term results from PCT studies often show a trade-off between individual-tree growth and net stand yield, while longer-term effects of PCT on tree growth and stand yield are less well documented. We used a 54-year-old PCT study to test long-term effects of forest density and thinning schedules on stand yield and tree-level characteristics in even-aged western larch (Larix occidentalis Nutt.) stands. The study has three target densities (494, 890, and 1680 trees·ha−1) crossed with three...

Concern over global environmental change and associated uncertainty has given rise to greater emphasis on fostering resilience through forest management. We examined the impact of standard silvicultural systems (including clearcutting, shelterwood, and selection) compared with unharvested controls on tree functional identity and functional diversity in three forest types distributed across the northeastern United States. Sites included the Argonne, Bartlett, and Penobscot Experimental Forests located in Wisconsin, New Hampshire, and Maine, respectively. We quantified functional trait means...