Treesearch

Great Basin bristlecone pine (Pinus longaeva D.K. Bailey) is a long-lived subalpine conifer native to the western United States. Bristlecone pine is considered a keystone species of high-elevation Great Basin sky island forests, yet detailed distribution data and information about constraining environmental factors for the species are lacking. We compiled a distribution dataset consisting of 490 individual bristlecone pine forest stands covering nearly 100,000 ha in Utah, Nevada, and California to enable improved monitoring of the species and enhanced understanding of forest succession...

Variations in hillslope soil moisture control forest hydrologic fluxes and storage pools, yet sparse observations combined with the complexity and heterogeneity of water movement and storage in the vadose zone can make temporal and spatial patterns and processes difficult to predict. We used two years of field observations of volumetric soil moisture at three depths (15, 30, and 100 cm) across five topographic positions (riparian, toeslope, sideslope, shoulder, and ridge) along three hillslope transects to better understand how soil moisture changes with hillslope position and through...

Fire suppression and anthropogenic land use have increased severity of wildfire in western U.S. dry conifer forests. Managers use fuels reduction methods (e.g., prescribed fire) to limit high-severity wildfire and restore ecological function to these fire-adapted forests. Many avian species that evolved in these forests, however, are adapted to conditions created by high-severity wildfire. To fully understand the ecological implications of fuels reduction treatments, we need to understand direct treatment effects and how treatments modulate subsequent wildfire effects on natural communities...

Buildings and the construction sector together account for about 39% of the global energy-related CO2 emissions. Recent building designs are introducing promising new mass timber products that have the capacity to partially replace concrete and steel in traditional buildings. The inherently lower environmental impacts of engineered wood products for construction are seen as one of the key strategies to mitigate climate change through their increased use in the construction sector. This chapter synthesizes the estimated carbon benefits of using engineered wood products and mass timber in...

In the Southern United States, a rising number of biomass facilities have created new market opportunities for forest landowners, consulting foresters, and loggers, which could increase the competition between the biomass market and pulpwood market for forest biomass. Thus, comparing the profits from conventional roundwood harvesting and biomass harvesting within a range of procurement distances could be crucial to make a harvest decision. In this study, we considered two harvesting systems: conventional and biomass. We developed a decision support tool to predict and compare the final...

Computational studies on the pyrolysis of lignin using electronic structure methods have been largely limited to dimeric or trimeric models. In the current work we have modeled a lignin oligomer consisting of 10 syringyl units linked through 9 b-O-40 bonds. A lignin model of this size is potentially more representative of the polymer in angiosperms; therefore, we used this representative model to examine the behavior of hardwood lignin during the initial steps of pyrolysis. Using this oligomer, the present work aims to determine if and how the reaction enthalpies of bond cleavage vary with...

Canonical lignification occurs via the coupling of phenolic radicals, in which chain extension can occur only from phenolic ends of growing polymer chains. Radical coupling of catechyl monomers, including caffeyl and 5-hydroxyconiferyl alcohols, gives rise to benzodioxane units in the polymer. Anticipating that a catechol could oxidize to its o-benzoquinone analog under the dehydrogenative (oxidative) conditions of lignification, we examined the possibility that an o-benzoquinone, as the diene component, could also incorporate into lignin via another mechanism, the Diels-Alder cycloaddition...

Persian walnut (Juglans regia L.) is a valuable economic plant used worldwide for its wood and nut fruit. In the current study, the genetic variation of 21 selected walnut genotypes from different regions of Iran was described using nut pomological properties, ISSR primers, and DNA analyses based on SSR primers. Nut pomology revealed nut weight of selected genotypes ranged from 12.1 to 17.5g (OR23). Kernel weight varied from 5.3 to 10.3g (OR23), and kernel fill percentage ranged from 43.4 to 62.7% (T12). PCR amplification with ISSR primers revealed 112 bands obtained with 91% polymorphism....

Genetic diversity underpins species conservation and management goals, and ultimately determines a species’ ability to adapt. Using freshwater environmental DNA (eDNA) samples, we examined mitochondrial genetic diversity using multigene metabarcode sequence data from four Oncorhynchus species across 16 sites in Oregon and northern California. Our multigene metabarcode panel included targets commonly used in population genetic NADH dehydrogenase 2 (ND2), phylogenetic cytochrome c oxidase subunit 1 (COI) and eDNA (12S ribosomal DNA) screening. The ND2 locus showed the greatest within-species...

Monitoring wildland fire burn severity is important for assessing ecological outcomes of fire and their spatial patterning as well as guiding efforts to mitigate or restore areas where ecological outcomes are negative. Burn severity mapping products are typically created using satellite reflectance data but must be calibrated to field data to derive meaning. The composite burn index (CBI) is the most widely used field-based method used to calibrate satellite-based burn severity data but important limitations of this approach have yet to be resolved. The objective of this study was focused...