Treesearch

Strong white oak sawtimber markets, partially attributed to the stave and cooperage industries, are encouraging forest managers to re-examine silvicultural practices for white oak (Quercus alba). We examined recruitment and retention of white oak in mixed oak–pine stands on the William B. Bankhead National Forest in northcentral Alabama. Stands were subjected to three thinning levels (residual basal areas of 75 ft2 /ac, 50 ft2 /ac, and no thinning) and three fire frequencies (dormant season burns of none, one, three fires) in a factorial design. Both thinning treatments reduced overstory...

Prior research has demonstrated the importance of water limitations and increasing temperatures on upland black spruce (Picea mariana [Mill.] B.S.P.) tree growth, which is a dominant component of the North American boreal forest. However, little work has been done to investigate the connectivity between growth and hydro‐climate in peatland black spruce systems. The boreal forest is the largest global terrestrial biome and is highly threatened due to current and projected increases in temperatures for the northern latitudes. Here we explore the dynamics among annual black spruce growth,...

This publication provides an overview of forest resources in South Dakota based on an inventory conducted by the USDA Forest Service, Forest Inventory and Analysis (FIA) program at the Northern Research Station (NRS) in cooperation with the South Dakota Department of Agriculture, Resource Conservation and Forestry Division. Estimates are based on field data collected using the FIA annualized sample design and are updated yearly. Information about the national and regional FIA program is available at http://fia.fs.fed.us. For the 2018 inventory, estimates for current variables such as area,...

Key Message We develop analytical methods and explore trends in disturbance interval via systematic forest inventory observations at a bioregional scale. Context Our study spans the dynamic ecotone at the intersection of southern boreal forest, mixed hardwood forest, and tallgrass prairie ecosystems in Minnesota, USA. Disturbance-related tree mortality is a major driver of demographic and successional change in this bioregion. Aims We aim to provide reliable disturbance estimates for forest ecology and economic research. Methods We develop methods applicable to any region with systematic...

Many of the ecological processes in the riparian forests and streams across the Pacific Northwest have become impaired through production forestry practices common prior to the 1990s. Some of these practices included forest harvest without stream buffers, removal of instream wood, road construction and use, and harvesting large proportions of watersheds. Passive ecological restoration (the use of natural processes of succession and disturbance to alleviate anthropogenic impacts over time) is a common practice used in the management of riparian forests previously subjected to production...

The Asian longhorned beetle (ALB, Anoplophora glabripennis) is an invasive pest species currently infesting major port cities in North America and Europe. There is limited knowledge regarding the pathways of movement across heterogeneous landscapes at local scales. This study models dispersal pathways using circuit theory in Worcester, Massachusetts, which has the largest ongoing ALB infestation in North America. Circuit theory–based dispersal modeling provides a means of predicting the movement of random walkers across a landscape comprising differential resistance to movement. Calibration...

Peatlands, which account for approximately 15% of land surface across the arctic and boreal regions of the globe, are experiencing a range of ecological impacts as a result of climate change. Factors that include altered hydrology resulting from drought and permafrost thaw, rising temperatures, and elevated levels of atmospheric carbon dioxide have been shown to cause plant community compositional changes. Shifts in plant composition a ect the productivity, species diversity, and carbon cycling of peatlands. We used hyperspectral remote sensing to characterize the response of boreal...

We investigated the roles of vegetation structure, micro-topographic relief, and predator activity patterns (time of day) on the perception of predatory risk of arctic ground squirrels (Urocitellus parryii), an abundant pan-Arctic omnivore, in Arctic Circle tundra on the North Slope of Alaska, where tundra vegetation structure has been predicted to change in response to climate. We quantified foraging intensity by measuring the giving-up densities (GUDs) of the arctic ground squirrels in experimental foraging patches along a heath–graminoid–shrub moist tundra gradient. We hypothesized that...

Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae) is a solitary and parthenogenetic egg parasitoid from China being introduced into North America (NA) as a biological control agent of 2 the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an extremely invasive and destructive pest of ash trees (Fraxinus spp.). Oobius agrili is being released over a broad geographical range in NA where photoperiod varies considerably during the season of parasitoid-host activity. We conducted laboratory studies to determine 1) if photoperiod-induced diapause is...

1. The unprecedented impact of human activities on nature has led scientists to propose we might now be in a new geological epoch: the Anthropocene. Significant human alterations of freshwater systems include massive changes to soil erosion–deposition dynamics, hydrological regimes via impoundment and diversion, land‐use conversion, chemical and nutrient pollution, and human‐assisted range expansion of invasive species. In this human‐dominated epoch, biodiversity, which includes all life on Earth, is at risk, and freshwater biodiversity shows the strongest examples of the extent of this...