Treesearch

DNA barcoding is a promising tool to combat illegal logging and associated trade, and the development of reliable and efcient analytical methods is essential for its extensive application in the trade of wood and in the forensics of natural materials more broadly. In this study, 120 DNA sequences of four barcodes (ITS2, matK, ndhF-rpl32, and rbcL) generated in our previous study and 85 downloaded from National Center for Biotechnology Information (NCBI) were collected to establish a reference data set for six commercial Pterocarpus woods. MLAs (BLOG, BP-neural network, SMO and J48) were...

The modulus of elasticity (MOE) and modulus of rupture (MOR) of graded lumber populations are commonly modeled by normal, lognormal, or Weibull distributions, but recent research has cast doubt on the appropriateness of these models. Such modeling has implications for ultimate performance and efficiency of resource use. It has been shown mathematically that the distribution of MOR in a graded subpopulation does not have the same theoretical form as the full, ungraded (or “mill-run”) population from which it was drawn; rather, its form is pseudo-truncated, exhibiting thinned tails. Although...

Wyoming big sagebrush is a widely distributed shrub that is native to the western United States. It occupies the largest area of the big sagebrush cover types. Wyoming big sagebrush ecosystems support hundreds of plant and animal species, including sage-grouse and many other sagebrush obligates, and Wyoming big sagebrush may be the single most important plant to sage-grouse. Its distribution has been reduced since European-American settlement, and it may become further reduced or altered by changes in fire regimes, spread of nonnative plants, conifer expansion, climate changes, and other...

Forest management, especially restoration, is informed by understanding the dominant natural disturbance regime. In many western North American forests the keystone disturbance is fire, and much research exists characterizing various fire regime parameters, although often only one or two parameters are addressed in individual studies. I performed a systematic review of the literature and meta-analysis of the derived data from 26 publications to characterize five parameters of the historical fire regime of ponderosa pine ecosystems in Colorado: fire frequency, severity, extent, seasonality,...

This synthesis summarizes information available in the scientific literature on historical patterns and contemporary changes in fuels and fire regimes in juniper communities of the Columbia and northern Great basins. Limited evidence suggests that many presettlement juniper woodlands and savannas had open stand structures, and they typically occurred in claypan soils or shallow soils on rocky sites. Few fire history studies have been conducted in these regions, and sample sizes were small and methodologies challenging, so historical fire regimes are poorly understood. Information was...

Wildfires and prescribed fires cause a range of impacts on forest soils depending on the interactions of a nexus of fire severity, scale of fire, slope, infiltration rates, and post-fire rainfall. These factors determine the degree of impact on forest soils and subsequently the need for post-fire soil management. Fire is a useful tool in landscape management but it can be benign or set off serious deteriorations in soil quality that lead to long-term desertification. If parts of the nexus are absent or not inherently risky, forest soil impacts can be relatively minor or nonexistent. A low...

Wildfires commonly increase nutrient, carbon, sediment and metal inputs to streams, yet the factors responsible for the type, magnitude and duration of water quality effects are poorly understood. Prior work by the current authors found increased nitrogen, phosphorus and cation exports were common the first 5 post-fire years from a synthesis of 159 wildfires across the western United States. In the current study, an analysis is undertaken to determine factors that best explain post-fire streamwater responses observed in those watersheds. Increased post-fire total nitrogen and phosphorus...

Western juniper occurs in the Pacific Northwest, California, and Nevada. Old-growth western juniper stands that established in presettlement times (before the 1870s) occur primarily on sites of low productivity such as claypan soils, rimrock, outcrops, the edges of mesas, and upper slopes. They are generally very open and often had sparse understories. Western juniper has established and spread onto low slopes and valleys in many areas, especially areas formerly dominated by mountain big sagebrush. These postsettlement stands (woodland transitional communities) are denser than most...

Plant modularity traits relevant to functions of on-spot persistence, space occupancy, resprouting after disturbance, as well as resource storage, sharing, and foraging have been underrepresented in functional ecology so far. This knowledge gap exists for multiple reasons. First, these functions and related traits have been considered less important than others (e.g., resource economics, organ-based traits). Second, collecting data for modularity traits can be difficult. Third, as a consequence of the previous points, there is a lack of standardized collection protocols. We now feel the...

Poplar wood was fractionated into a water-insoluble cellulosic solid (WIS) fraction and a spent liquor that contained mainly dissolved ignin and xylan using an acid hydrotrope, p-Toluenesulfonic acid (p-TsOH), at low temperatures (≤90 °C). Reaction-kinetics-based severities were used to scale-up fractionation using 100 g wood at p-TsOH concentration 50 wt% and 90 °C for 112 min. The WIS and spent iquor from a scale-up run were used to produce bioethanol and furfural, respectively. At 15% WIS loading (w/v), maximal ethanol concentration was 52.47 g/L with a fermentation efficiency of 68.3%....