Treesearch

Understanding differences in physiological and growth strategies in low-light environments among upland oak species may help managers address the challenges of oaks' poor regeneration. Gas exchange and chlorophyll content were measured for northern red oak (Quercus rubra L.), chestnut oak (Quercus prinus L.), and white oak (Quercus alba L.) germinants grown at 25%, 18%, and 6% of full sun in one of two native forest soil mixes for two summers. Northern red and chestnut oak photosynthesis at saturating light (Amax, mass) increased by 23%-36% as light levels increased from 6% to 25% of full...

An expansive mountain pine beetle (MPB) epidemic is currently impacting North American forests (Raffa et al. 2008). As beetle-attacked trees die, lose their needles, and eventually fall to the ground, there are substantial changes in stand structure. These fuel changes likely affect both surface and crown fire behavior, but there is not yet a consensus among experts regarding the nature and magnitude of these effects (Jenkins et al. 2008). Simard et al. (2011; hereafter referred to as SRGT) used linked crown fire models implemented in the NEXUS crown fire modeling system (Scott and...

Wildland managers need detailed information about the responses of invasive species to fire and the conditions that increase site invasibility in order to effectively manage fire without introducing or increasing populations of invasive plants. Literature reviews and syntheses of original research are important sources of this information, but the usefulness of a review is limited by the quantity, quality, and geographic coverage of information available when it is written. This study analyzed the information available for 61 syntheses published in the Fire Effects Information System...

Wildlife management often hinges upon an accurate assessment of population density. Although undeniably useful, many of the traditional approaches to density estimation such as visual counts, livetrapping, or mark–recapture suffer from a suite of methodological and analytical weaknesses. Rare, secretive, or highly mobile species exacerbate these problems through the reality of small sample sizes and movement on and off study sites. In response to these difficulties, there is growing interest in the use of noninvasive survey techniques, which provide the opportunity to collect larger...

People have looked for reasons why kids might not be going outdoors as much as they once did. One possible reason is the increasing use of electronic media and technology, such as the Internet and video games. Some researchers point out, however, that kids may be using cell phones and other electronic media outdoors. These researchers wonder how much media use affects the amount of time kids spend outdoors. The effect that electronic media and technology have on kids’ time outdoors, therefore, is not known. You may recall that previous studies had not looked at kids across the entire...

The research you will read about in this Natural Inquirer was conducted by scientists working at the Institute of Pacific Islands Forestry, or IPIF. Located in Hilo, HI, scientists at IPIF study a range of environmental topics in Hawai‘i and the Pacific Islands.

The Sierra Ancha International Cooperative Program on Assessment and Monitoring of Air Pollution Effects on Forests study site or (SAEF-ICP II) is part of an international network of cooperative forest monitoring sites spread throughout Europe and the United States. The United Nations Economic Commission for Europe established the ICP II network in 1985 to monitor long-term effects of transboundary air pollution. The Sierra Ancha Experimental Forest was chosen to be a part the U.S.'s network because it is the southernmost Experimental Forest in the contiguous U.S., and because it is...

The effects of pretreatment by dilute acid and sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) on substrate morphology, cell wall physical and chemical structures, along with the subsequent enzymatic hydrolysis of lodgepole pine substrate were investigated. FE-SEM and TEM images of substrate structural morphological changes showed that SPORL pretreatment resulted in fiber separation, where SPORL high pH (4.2) pretreatment exhibited better fiber separation than SPORL low pH (1.9) pretreatment. Dilute acid pretreatment produced very poor fiber separation, consisting...

This study demonstrated the potential of simultaneously recovering cellulosic solid residues (CSR) and producing cellulose nanocrystals (CNCs) by strong sulfuric acid hydrolysis to minimize cellulose loss to near zero. A set of slightly milder acid hydrolysis conditions than that considered as “optimal” were used to significantly minimize the degradation of cellulose into soluble sugars that cannot be economically recovered, but resulted in CSR that is easily recoverable through conventional centrifuge. It was found that the window for simultaneous recoveries of CSR and producing high...

Solution-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy of plant cell walls is a powerful tool for characterizing changes in cell wall chemistry during the hydrothermal pretreatment process of wheat straw for second-generation bioethanol production. One-bond 13C-1H NMR correlation spectroscopy, via an heteronuclear single quantum coherence experiment, revealed substantial lignin β-aryl ether cleavage, deacetylation via cleavage ofthe natural acetates at the 2-O-and 3-O-positions of xylan, and uronic acid depletion via cleavage of the (1 → 2)-linked 4-O-methyl-α-D-g...