Treesearch

This publication provides an overview of forest resources in Vermont based on inventories conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program of the Northern Research Station. Since 1999, FIA has employed an annual inventory measuring data on a nominal 20 percent of sample plots each year. For the 2013 inventory, estimates for current variables such as area, volume, and biomass are based on 1052 plot samples collected from 2009-2013. Change variables such as net growth, removals, and mortality are based on 964 samples collected in 2004-2008 and resampled in...

Presents recent Michigan forest industry trends; production and receipts of industrial roundwood; and production of saw logs, veneer logs, pulpwood, and other products in 2008. Logging residue generated from timber harvest operations is reported, as well as wood and bark residue generated at primary wood-using mills and disposition of mill residues.

Wood products have many environmental advantages over nonwood alternatives. Documenting and publicizing these merits helps the future competitiveness of wood when climate change impacts are being considered. The manufacture of wood products requires less fossil fuel than nonwood alternative building materials such as concrete, metals, or plastics. By nature, wood is composed of carbon that is captured from the atmosphere during tree growth. These two effects—substitution and sequestration—are why the carbon impact of wood products is favorable. This article shows greenhouse gas emission...

We achieved a multiscale description of the thermal conductivity of cellulose nanocrystals (CNCs) from single CNCs (~­0.72−5.7 W m−1 K−1) to their organized nanostructured films (~­0.22−0.53 W m−1 K−1) using experimental evidence and molecular dynamics (MD) simulation. The ratio of the approximate phonon mean free path (~­1.7−5.3 nm) to the lateral dimension of a single CNC (~­5−20 nm) suggested a contribution of crystal−crystal interfaces to polydisperse CNC film's heat transport. Based on this, we modeled the thermal conductivity of CNC films using MD-predicted single crystal and...

Anisotropy and temperature dependence of structural, thermodynamic and elastic properties of crystalline cellulose Iβ were computed with first-principles density functional theory (DFT) and a semi-empirical correction for van der Waals interactions. Specifically, we report the computed temperature variation (up to 500 K) of the monoclinic cellulose Iβ lattice parameters, constant pressure heat capacity, Cp, entropy, S, enthalpy, H, the linear thermal expansion components, ξI , and components of the isentropic and isothermal (single crystal) elastic stiffness matrices, CS ij (T ) and CT ij...

The concept of historic range of variability (HRV) is briefly evaluated within the context of its application in ecosystem management over the past two decades. Despite caveats to the contrary, an implicit assumption continues to emerge of climatic stationarity, and, by corollary, that presettlement centuries provide an appropriate reference period. This is examined from the perspective of historic climate change and ecosystem response. As a means of developing reference prescriptions and management targets, HRV is generally inappropriate, although if historic periods are used for reconstru...

There has been a great deal of discussion in the scientific literature and in traditional forest management literature about forest restoration, ecological restoration, adaptive and active management for restoring forest ecosystems, and a variety of linked topics. The USDA Forest Service manages 193 million acres of forest and grasslands for a variety of uses, and conducts restoration work on many of these lands. In addition, the Research and Development branch of the Forest Service works to develop knowledge to help in managing the Nation's forests and grass lands. In the context of...

Although it is well established that exposure to nearby nature can help reduce stress in individuals, the shape of the dose-response curve is entirely unclear. To establish this dose-response curve, we recruited 160 individuals for a laboratory experiment. Participants engaged in the Trier Social Stress Test (TSST) to induce psychological stress, and were then randomly assigned to view one of ten, 6-min, 3-D videos of neighborhood streets. The density of tree cover in the videos varied from 1.7% to 62.0%. We measured their stress reactions by assessing salivary cortisol and skin conductance...

Export of dissolved organic carbon from lakes and streams has increased throughout Europe and North America over the past several decades. One possible cause is altered deposition chemistry; specifically, decreasing sulfate inputs leading to changes in ionic strength and dissolved organic carbon solubility. To further investigate the relationship between deposition chemistry and dissolved organic carbon export in peatlands, a field experiment was conducted to compare the pore water chemistry and peat microbial enzyme activity of mesocosms receiving sulfate amendments to mesocosms receiving...

Many international protocols (e.g., REDD+) are developing inventories of ecosystem carbon stocks and fluxes at country and regional scales, which can include peatlands. As the only nationally implemented field inventory and remeasurement of forest soils in the US, the USDA Forest Service Forest Inventory and Analysis Program (FIA) samples the top 20 cm of organic soils, but there is a large unsampled fraction of soil carbon stored in America’s peatland forests. Improved methods could allow the FIA program to more comprehensively estimate soil carbon stocks and stock change in forested...