Treesearch

For several decades, southern California experienced the worst ozone pollution ever reported. Peak ozone concentrations have, however, declined steadily since 1980. In this study, the structural injuries underlying ozone symptoms in needles of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) collected in summer 2006 from one of the most polluted sites in the San Bernardino Mountains were investigated using serial sections examined by light and electron microscopy. Ozone-specific light-green diffuse mottling was observed in the currentyear needles, whereas older foliage showed brownish...

In January 2013, the U.S. Department of Agriculture Forest Service's Rocky Mountain Research Station and National Technology and Development Centers performed experiments to evaluate the potential for rifle bullets to ignite organic matter after striking hard surfaces. Outdoor target shooting is often suspected as a wildfire cause, but investigators currently do not have adequate scientific data to support this conclusion. The purpose of this study was to determine if ignitions are possible under worst-case circumstances and to identify the physical process by which ignitions can occur.

An assessment of the relative importance of vegetation change and disturbance as agents of landscape change under current and future climates would (1) provide insight into the controls of landscape dynamics, (2) help inform the design and development of coarse scale spatially explicit ecosystem models such as Dynamic Global Vegetation Models (DGVMs), and (3) guide future land management and planning. However, quantification of landscape change from vegetation development and disturbance effects is difficult because of the large space and long time scales involved. Comparative simulation...

This design guide summarizes recent research on the corrosion of metals in treated wood, presents design strategies to minimize corrosion of metals in contact with treated wood, and is targeted toward engineers, architects, builders, and homeowners. The guide is organized as a “question and answer” document. While the questions are arranged in a logical order, each question and answer are self-contained. Special efforts have been made to provide a comprehensive bibliography to direct the reader to further information on each question. The document was created to give practical “hands-on”...

In the US, wildfires and prescribed burning present significant challenges to air regulatory agencies attempting to achieve and maintain compliance with air quality regulations. Fire emission factors (EF) are essential input for the emission models used to develop wildland fire emission inventories. Most previous studies quantifying wildland fire EF of temperate ecosystems have focused on emissions from prescribed burning conducted outside of the wildfire season. Little information is available on EF for wildfires in temperate forests of the conterminous US. The goal of this work is to...

We present a collection of papers derived from the 2012 Forest Inventory and Analysis (FIA) Symposium held on December 4-6, 2012 in Baltimore, MD, USA. The symposium featured 128 oral presentations with nearly 200 attendees from the United States and other countries. A proceedings from the symposium included 75 papers as well as abstracts for all presentations and posters. The symposium theme, Moving from Status to Trends, focused on the ability to perform trend or time series analysis using national forest inventory data. A wide range of topics were covered including forest products,...

The five field sampling methods tested for this study differed in richness and Simpson's Index values calculated from the raw data. How much the methods differed, and which ones were most similar to each other, depended on which diversity measure and which type of data were used for comparisons. When the number of species (richness) was used as a measure of similarity, the historic method captured significantly fewer species than the Daubenmire, modified-Whittaker, or Forest Inventory and Analysis (FIA) methods but similar numbers as the small-scale nested circular plot. When Simpson's...

One key barrier to converting woody biomass to biofuel through the sugar platform is the low efficiency of enzymatic cellulose saccharification due to the strong recalcitrance of the crystalline cellulose. Significant past research efforts in cellulosic biofuels have focused on overcoming the recalcitrance of lignocelluloses to enhance the saccharification of the recalcitrant cellulose. However, in this work [1,2], we demonstrate the conversion of recalcitrant cellulose into cellulosic nanomaterials, which have attracted a great deal of attention recently due to their unique properties and...

The statistical analysis of wildfire activity is a critical component of national wildfire planning, operations, and research in the United States (US). However, there are multiple federal, state, and local entities with wildfire protection and reporting responsibilities in the US, and no single, unified system of wildfire record-keeping exists. To conduct even the most rudimentary interagency analyses of wildfire numbers and area burned from the authoritative systems of record, one must harvest records from dozens of disparate databases with inconsistent information content. The onus is...