Treesearch

The Forest Inventory Analysis (FIA) unit of the Southern Research Station annually compiles, analyzes, and reports canvass data of pulpmills in the South. This report for 2017 presents the findings of a 100-percent canvass of pulpmills that used roundwood or wood residues from the 13 Southern States. Of the 77 mills canvassed, 60 responded. For the 17 mills that did not respond, previous canvass data and other sources of information were used for the findings reported in this publication. Regional conversion factors were used to convert mill data reported in nonstandard units to standard...

Mangroves can sequester and store massive amounts of CO2from the atmosphere in the form of live plant and detrital biomass. Large amounts of autochthonous and allochthonous carbon (C) are also stored in sediments, where waterlogged and anoxic conditions inhibit microbial breakdown of organic matter. As a result, C buried in sediments of mangroves can remain there for millennia if left undisturbed, making them critical long-term C sinks. These high levels of aboveground and belowground C stocks have elevated the importance of mangroves and other blue carbon habitats in climate change...

Promoting patchy recruitment of shade tolerant tree species into the midstory is an important step in developing structural diversity in second-growth stands. Variable-density thinning (VDT) has been proposed as a strategy for accelerating structural diversity, as its combination of within-stand treatments (harvest gaps, thinning, and non-harvested skips) should create variable overstory and understory conditions. Here we report on western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedling and sapling densities in five mixedconifer stands and Sitka spruce (Picea sitchensis (Bong.) Carr.)...

Windbreaks are an agroforestry practice used to provide simultaneous economic, environmental and social benefits that occur when trees are deliberately integrated into an agroecosystem. To date, no systematic review has been conducted on windbreak adoption in the U.S., which is needed to assess whether broader trends exist that may affect future research, extension delivery and policy development. This synthesis covers windbreak adoption studies in the U.S. from the earliest identified study in 1949 through 2020. A key finding from this synthesis is that producers use windbreaks on...

Warming climate and resulting declines in seasonal snowpack have been associated with drought stress and tree mortality in seasonally snow-covered watersheds worldwide. Meanwhile, increasing forest density has further exacerbated drought stress due to intensified tree–tree competition. Using a uniquely detailed data set of population-level forest growth (n= 2,495 sampled trees), we examined how inter-annual variability in growth relates to snow volume across a range of forest densities (e.g., competitive environments) in sites spanning a broad aridity gradient across the United States....

Process ecosystem models are useful tools to provide insight on complex, dynamic ecological systems, and their response to disturbances. The biogeochemicalmodel PnET-BGC was modified and tested using field observations from an experimentally whole-tree harvested northern hardwoodwatershed (W5) at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. In this study, the confirmed model was used as a heuristic tool to investigate long-termchanges in hydrology, biomass accumulation, and soil solution and streamwater chemistry for three different watershed cutting intensities (40%,...

Black ash (Fraxinus nigra) is native to lowland forests of the western Great Lakes region, USA, where it often comprises a majority of trees. Like all native ash in North America, black ash is threatened by emerald ash borer (EAB; Agrilus planipennis), but the impacts from EAB mortality may be particularly severe in these forests given the foundational role of black ash at regulating ecosystem function. Compounding the problem is that associated tree species occur in low abundance and their abundance may be further reduced as habitat declines with climate change. These converging threats...

The emerald ash borer (EAB) has killed ash species (Fraxinus L.) in much of eastern North America, but it has yet to reach the vast ash wetlands in northern Minnesota, USA. In these wetlands, a single species, black ash (Fraxinus nigra Marsh.) comprises a majority of trees and has a foundational role in controlling ecosystem function. Given the likelihood of wide-spread mortality of black ash from EAB and the likelihood of severe ecosystem impacts, we examined the potential for co-occurring tree species to replace black ash, either through gap filling in the overstory or release from the...

This paper is intended as an assessment of the state of knowledge and development of semiochemical methods for control of bark beetles (Coleoptera: Curculionidae) in western North America and as a roadmap for future research and development in this field. It is based on a keynote presentation given at the symposium Managing Bark and Ambrosia Beetles with Semiochemicals, held in 2018 in Vancouver, British Columbia, Canada, at the Joint Meeting of the Entomological Society of America, the Entomological Society of Canada, and the Entomological Society of British Columbia. We describe currently...

Managed forests generally produce high water quality, but degradation is possible via sedimentation if proper management is not implemented during forest harvesting. To mitigate harvesting effects on total watershed sediment yield, it is necessary to understand all processes that contribute to these effects. Forest harvesting best management practices (BMPs) focus almost exclusively on overland sediment sources, whereas in-and-near stream sources go unaddressed although they can contribute substantially to sediment yield. Thus, we propose a new framework to classify forest harvesting...