Treesearch

Assessing risks of uncertain but potentially damaging events, such as environmental disturbances, disease outbreaks and pest invasions, is a key analytical step that informs subsequent decisions about how to respond to these events. We present a continuous risk measure that can be used to assess and prioritize environmental risks from uncertain data in a geographical domain. The metric is influenced by both the expected magnitude of risk and its uncertainty.We demonstrate the approach by assessing risks of human-mediated spread of Asian longhorned beetle (ALB, Anoplophora glabripennis) in...

As impacts of climate change expand, determining accurate measures of forest biomass and associated carbon storage in forests is critical. We present sampling guidance for 12 combinations of percent error, plot size, and alpha levels by disturbance regime to help determine the optimal size of plots to estimate aboveground biomass and carbon in an old-growth Central Hardwood forest. The analyses are based on five 100-percent inventories covering a 66-year time period. Disturbance regimes during that time included periods of grazing, low tree mortality, and high tree mortality. The size and...

"Simple taper" is set of linear equations that are based on stem taper rates; the intent is to provide taper equation functionality to field foresters. The equation parameters are two taper rates based on differences in diameter outside bark at two points on a tree. The simple taper equations are statistically equivalent to more complex equations. The linear equations in simple taper were developed with data from 11,610 stem analysis trees of 34 species from across the southern United States. A Visual Basic program (Microsoft®) is also provided in the appendix. A correction to Table 2, on...

The Pennsylvania Regeneration Study was initiated in 1989 because of concerns about a long history of stress on oak/hickory (Quercus/Carya) forests from herbivory and other factors. The study, which addresses the need for landscape-level information about regeneration quality and abundance, comprises a suite of regeneration indicator measurements installed on a subset of Forest Inventory and Analysis monitoring plots. The State's oak/hickory forests have been under increasing stress because aging stands that originate from large-scale disturbances from more than 100 years ago are inundated...

Bur oak (Quercus macrocarpa Michx.) is a classic savanna species with a range that covers much of the eastern United States. Because savannas are an endangered habitat in North America, significant restoration efforts are in progress across much of the range of bur oak. For open sites being planted with bur oaks as well as fully stocked sites that are being thinned to create savanna conditions, an understanding of potential maximum crown area is of great utility. Between 2013 and 2015, 45 open-grown bur oaks ranging in size from 3.6 to 36.1 inches diameter at breast height (d.b.h.) were...

SITEQUAL is a computerized expert system that uses a number of easily determined soil conditions associated with physical structure, available moisture, available nutrients, and aeration to estimate site index for 14 southern hardwood species. The original program was written in the Basic language by Harrington and Casson (1986) based on the field methods for site evaluation developed by Baker and Broadfoot (1979). Unfortunately, this version of SITEQUAL does not operate as a stand-alone application, but rather requires a compiler that no longer works with modern operating systems. I have...

Prescribed fire is commonly used for restoring and managing oak woodlands but raises concern over the risk of value loss to timber products. We used a long-term prescribed burning study to quantify standing timber volume and stumpage value, fire scar presence and size, and timber value loss in comparison to unburned stands. Three study treatments were initiated in 1949: annual burning (Annual; 1-year fire return interval), periodic burning (Periodic; 4-year fire return interval), and no burning (Control). In 2013, we measured the diameter at breast height (d.b.h.) and merchantable height...

Microwave-assisted liquefaction has shown potential for rapid thermal processing of lignocellulosic biomass. The efficiency of microwave heating depends largely on the dielectric properties of the materials being heated. The objective of this study was to investigate the dynamic interactions between microwave energy and the reaction system during the liquefaction of a woody biomass sample. The dielectric properties of poplar wood particles, model compounds representing the three main chemical components of wood, and individual liquefaction solvent components, along with their mixtures,...

Large numbers of migratory bats are killed every year at wind energy facilities. However, population-level impacts are unknown as we lack basic demographic information about these species. We investigated whether fatalities at wind turbines could impact population viability of migratory bats, focusing on the hoary bat (Lasiurus cinereus), the species most frequently killed by turbines in North America. Using expert elicitation and population projection models, we show that mortality from wind turbines may drastically reduce population size and increase the risk of extinction. For example,...

Commercial thinning in hardwood stands is generally applied to reduce overcrowding and to favor the development of desired residual species until the stand is mature. In mixed hardwood stands, commercial thinning also provides an opportunity to promote vigorous overstory oaks (Quercus spp.) that will serve as sources of acorns and advanced seedlings needed to regenerate oaks in the next stand. Forest managers need information on sustaining and increasing the number of overstory oaks at mid-rotation when the stand is still several decades from maturity. In this study, crown class dynamics...