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Freeze-dried nanofibrillated cellulose based-aerogels were produced from cellulosic pulps extracted from Eucalyptus urograndis. Nanofibers were isolated under high pressure and modified with TEMPO-mediated oxidation and/or hydroxyapatite (HAp) to observe potential changes in mechanical properties. Two degrees of oxidation (DO), 0.1 and 0.2, were achieved as measured by conductimetric titration. Oxidized and non-oxidized samples were modified with HAp at a ratio of HAp:cellulose of 0.2:1. Morphology (FE-SEM), pore size, surface area, and mechanical properties were obtained to characterize...

This study demonstrates regioselective oxidation of cellulose nanowhiskers using 2.80–10.02 mmols of sodium periodate per 5 g of whiskers followed by grafting with methyl and butyl amines through a Schiff base reaction to obtain their amine derivatives in 80–90 % yield. We found a corresponding increase in carbonyl content (0.06–0.14 mmols/g) of the dialdehyde cellulose nanowhiskerswith the increase in oxidant as measured by titrimetric analysis and this was further evidenced by FT-IR spectroscopy. Grafting of amine compounds to the oxidized cellulose nanowhiskers resulted in their amine...

The Interior West Forest Inventory and Analysis (IWFIA) Program of the USDA Forest Service, Rocky Mountain Research Station, as part of our National Forest System cooperative inventories, conducted a forest resource inventory on the Idaho Panhandle National Forest (IPNF) using a nationally standardized mapped-plot design (for more details see "The inventory methods" section). This report presents the highlights of the 2001 inventory using variables and summaries commonly requested by IWFIA users. The data could be summarized in other ways for different purposes (see "For further information...

Armillaria species display diverse ecological behaviors from beneficial saprobe to virulent pathogen. Armillaria solidipes, a causal agent of Armillaria root disease (ARD), is a virulent primary pathogen with a broad host range. ARD is responsible for reduced forest productivity as a result of direct tree mortality and non-lethal cryptic infections that impact growth. It is typically more severe in intensively managed forests and in maladapted trees. Armillaria isolates collected from more than 500 climatically diverse, georeferenced plots established throughout the western USA were...

We surveyed black spruce stands within 0.5 miles of US Forest Service Forest Inventory and Analysis (FIA) plots and compared dwarf mistletoe status with that of the FIA and Minnesota Department of Natural Resources (DNR) forest inventories. Our results differed from FIA results in 3 of 16 stands with FIA plots, with FIA most often not recording dwarf mistletoe in infested stands. The infestation status of 140 of 202 surrounding stands was the same as recorded for the nearby FIA plot. Minnesota DNR forest inventory identified dwarf mistletoe in only 26 of 112 infested stands. Using only the...

Studies designed to understand species distributions and community assemblages typically use separate analytical approaches (e.g., logistic regression and ordination) to model the distribution of individual species and to relate community composition to environmental variation. Multilevel models (MLMs) offer a promising strategy for integrating species and community-level analyses. Here, we demonstrate how MLMs can be used to analyze differences in species composition of communities across environmental gradients. We first use simulated data to show that MLMs can outperform three standard...

This report presents an overview of the El Yunque National Forest, which is also designated as Luquillo Experimental Forest, in northeastern Puerto Rico. The principal topics include the environmental setting (geology, soils, and climate), environmental gradients, arborescent flora, vertebrate fauna, and forest management (i.e., plantations, silvicultural operations, planning, research, and designated land uses). A chronology from the time of European discovery to the present outlines major events in the Luquillo Experimental Forest, including an early presence of indigenous peoples,...

Background: Nut-bearing trees, including oaks (Quercus spp.), are considered to be highly dispersal limited, leading to concerns about their ability to colonize new sites or migrate in response to climate change. However, estimating seed dispersal is challenging in species that are secondarily dispersed by animals, and differences in disperser abundance or behavior could lead to large spatio-temporal variation in dispersal ability. Parentage and dispersal analyses combining genetic and ecological data provide accurate estimates of current dispersal, while spatial genetic structure (SGS)...

The constant nutrient addition technique has been used extensively to measure nutrient uptake in streams. However, this technique is impractical for large streams, and the pulse nutrient addition (PNA) has been suggested as an alternative. We developed a computer model to simulate Monod kinetics nutrient uptake in large rivers and used this model to evaluate the sensitivity of the PNA technique. We parameterize our model using the average hydrogeomorphological estimates from a pulse release study of ammonium in the Snake River, WY, and used this study to demonstrate how data from a field...

This analysis examines wildlife poisoning from coal combustion waste (CCW) in the context of EPA's proposed policy that would allow continued use of surface impoundments as a disposal method. Data from 21 confirmed damage sites were evaluated, ranging from locations where historic poisoning has led to corrective actions that have greatly improved environmental conditions to those where contamination has just recently been discovered and the level of ecological impacts has yet to be determined. The combined direct and indirect cost of poisoned fish and wildlife exceeds $2.3 billion, which...