Treesearch

A new method is described for producing high-lignin-containing and lignin-free cellulose nanocrystals from poplar wood (HLCNCs and LFCNCs, respectively). This was accomplished by first hydrothermally treating the poplar wood fibers at 170°C for 45 min in a Parr reactor. For obtaining HLCNCs, the treated fibers were directly hydrolyzed by 64% sulfuric acid whereas for LFCNCs, the fibers were delignified prior to the acid hydrolysis. The CNCs thus produced were characterized using spectroscopy, microscopy, and diffraction techniques and compared with bleached kraft pulp-CNCs. The comparison...

Forestry practitioners often need to identify old-growth stands because of their high conservation value. To identify the structural and compositional characteristics potentially unique to old-growth northern white-cedar (Thuja occidentalis L.) stands, we compared 16 old-growth stands and 17 partially harvested stands in Maine, USA and New Brunswick, Canada. Potential old-growth predictors included common structural metrics such as basal area (BA), quadratic mean diameter (QMD), large tree (≥40 cm diameter at breast height) density, and volumes of coarse woody debris (CWD), along with six...

White pine (Pinus strobus) is commonly found in naturally regenerated even-aged stands on former agricultural lands throughout its range. These stands can be managed for rapid production of high-quality sawtimber, and are thus a valuable timber resource. Yet, periodic growth decline and mortality events have occurred, such as that observed in the late 1990s in southern Maine, USA. The present study uses increment measurements from white pine tree cores collected in the early 2000s to compare increment chronologies in high- and low-mortality stands in southern Maine. Periods and severity of...

Spatial and temporal influences on the winter (December-March) stormflow characteristics of fifteen United States Geological Survey (USGS)-gaged watersheds in the Southern Blue Ridge Mountains are identified: (1) watershed-scale differences in geomorphology; (2) continental-scale teleconnections during periods of wetness/dryness (based on the relative amount of winter precipitation over a consistent 20 year dataset); and (3) land cover in the context of soil parent material (e.g., development on alluvium/colluvium). Multiple regression was used to determine how much variance could be...

This report describes modeling of historical range of variability and alternative management scenarios in the upper Yuba River watershed, Tahoe National Forest, California. We discuss the need for this study with respect to the historical and contemporary context of the northern Sierra Nevada landscape, including background on the range of variability concept and the use of simulation modeling to quantify it. We simulated the dynamics in vegetation driven by wildfire during the historical reference period (ca. 1550-1850). Based on the output, we quantified the range of variability in...

We mapped native, endemic, and introduced (i.e., exotic) tree species counts, relative basal areas of functional groups, species basal areas, and forest biomass from forest inventory data, satellite imagery, and environmental data for Puerto Rico and the Virgin Islands. Imagery included time series of Landsat composites and Moderate Resolution Imaging Spectroradiometer (MODIS)-based phenology. Environmental data included climate, land-cover, geology, topography, and road distances. Large-scale deforestation and subsequent forest regrowth are clear in the resulting maps decades after...

The U.S. Forest Service has a long, rich history of helping to steward the nation's fish and aquatic resources and contributing to the broader fish and aquatic conservation and scientific community in the United States and worldwide. The agency recently updated its national strategy for fish and aquatic resource stewardship. The new strategy builds on 30 years of lessons learned through implementing the agency's original Rise to the Future: National Fish and Aquatic Strategy, the first national freshwater fisheries strategy by a federal agency. It also addresses 21st century challenges,...

Terrestrial gastropods are part of one of the most vulnerable taxonomic groups, mollusks, but receive relatively little conservation attention. This is partially due to the paucity of peer-reviewed statistical evaluations of common survey techniques. From 2010 to 2014, we conducted a massive survey for terrestrial gastropods in a montane region centered on northern Idaho and including portions of northeastern Washington and northwestern Montana, USA. We fused several commonly used gastropod survey techniques (cover board traps baited with beer or water, pitfall traps, visual search, and...

Catchments with minimal disturbance usually have low dissolved inorganic nitrogen (DIN) export, but disturbances and anthropogenic inputs result in elevated DIN concentration and export and eutrophication of downstream ecosystems. We studied streams in the southern Appalachian Mountains, USA, an area dominated by hardwood deciduous forest but with areas of valley agriculture and increasing residential development. We collected weekly grab samples and storm samples from nine small catchments and three river sites. Most discharge occurred at baseflow, with baseflow indices ranging from 69%...

This report constitutes the third full report of annualized inventory on Ohio forest land and summarizes field data collected from 2011 through 2016. Ohio has 8.0 million acres of forest land containing 103 tree species and 50 forest types. Net cubic-foot and sawtimber volumes continued to increase, as did the area occupied by large diameter stands. Growing-stock volume remained stable overall, though it decreased 3 percent on private land since 2006. The net-growth-to-harvest-removals ratio dropped from 2.3:1 in 2011 to 1.6:1 in 2016. Invasive insects have had a substantial impact on...