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Poplar NE222 (Populus deltoides Bartr. ex Marsh P. nigra L.) wood chips were pretreated in a 390 L pilot-scale rotating wood-pulping digester using a dilute sulfite solution of approximately pH 1.8 at 160°C for 40 min for bioconversion to ethanol and lignosulfonate (LS). An estimated combined hydrolysis factor (CHF) of 3.3 was used to scale the sulfite pretreatment temperature and time from laboratory bench scale experiments, which balanced sugar yield and inhibitor formation to facilitate high titer ethanol production through fermentation using S. cerevisiae YRH400 without detoxification....

The Lake States ceded territories are the portions of northern Michigan, northeastern Minnesota, and northern Wisconsin that were ceded by tribes of the Ojibwe to the government of the United States of America in the treaties of 1836, 1837, 1842, and 1854. The tribes retain rights to hunt, fish, and gather in the 1837, 1842, and 1854 treaty areas. This report summarizes the results of a series of forest inventories in the region between 1980 and 2013. Inventory results show the region has 30.7 million acres of forest land with forests covering 65.3 percent of the total land area. Forest...

This publication provides an overview of forest resources in Delaware based on inventories conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program of the Northern Research Station. From 2004-2013, FIA employed an annual inventory with a cycle length of 5 years, measuring data on 20 percent of all sample plots each year in Delaware. Beginning in 2014, FIA is on a 7-year cycle, inventorying 14.3 percent of all plots annually. For the 2014 inventory, estimates for current variables such as area, volume, and biomass are based on 393 plots collected from 2009-2014....

In this study, we examined the potential of using a time-of-flight (TOF) acoustic wave method to evaluate thinning and biosolid fertilization effects on acoustic velocity of trees and modulus of elasticity (MOE) of structural lumber in a 76-year-old Douglas-fir (Pseudotsuga menziesii, (Mirb., Franco)) experimental stand. The stand consisted of four treatments: control, thinned, biosolid fertilized, and a combined thinned and fertilized treatment, each with three replicates on 0.08 hectare plots. Four trees were selected in each plot using a stratified random sample based on the plot...

The Janzen -- Connell hypothesis proposes that specialized herbivores maintain high numbers of tree species in tropical forests by restricting adult recruitment so that host populations remain at low densities. We tested this prediction for the large timber tree species, Swietenia macrophylla, whose seeds and seedlings are preyed upon by small mammals and a host-specific moth caterpillar Steniscadia poliophaea, respectively. At a primary forest site, experimental seed additions to gaps -- canopy-disturbed areas that enhance seedling growth into saplings -- over three years revealed lower...

Trees within an urban community provide measurable aesthetic, social, ecological and economic benefits. When growing normally and stably, they contribute to making a city more livable and comfortable for its inhabitants. However, as large physical structures in close proximity to people and property, their failure can cause harm. The science of tree stability analysis uses both biological and engineering principles in determining a tree’s structural soundness and predicting the probability of failure. Nondestructive testing methods of locating and quantifying wood decay and defect are used...

Cellulose nanocrystals (CNC) have recently received much attention in the global scientific community for their unique mechanical and optical properties. Here, we conducted the first detailed exploration of the basic properties of CNC, such as morphology, crystallinity, degree of sulfation and yield, as a function of production condition variables. The rapid cellulose depolymerization and sulfation reactions under concentrated acid concentrations of around 60 wt% resulted in a very narrow operating window for CNC production. We found that CNC yields as high as 70 wt% from a bleached...

Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia is thought to suppress lignin decomposition, yet potential effects of oxygen (O2) variability in surface soils have not been explored. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical forest soils during ten-week laboratory incubations. We used synthetic lignins labeled with 13C in either of two positions (aromatic methoxyl or propyl side chain Cß) to...

Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported...

Traditionally it has been accepted that the cell walls are made up of microfibrils which are partly crystalline. However, based on the recently obtained Raman evidence that showed that the interior of the microfibril was significantly disordered and water accessible, a new model is proposed. In this model, the molecular chains of cellulose are still organized along the fibril direction but, at the local level, the chains retain significant degrees of freedom. The new fibril model has implications for not only formation of inter-chain H-bonds and therefore, cellulose ultrastructure but...