Treesearch

Natural forest disturbances, which drive succession and development, differ in extent, severity, and return interval and range from frequent, gap-scale disturbances, to infrequent stand-replacing events. Most studies have focused on natural disturbances near the ends of the disturbance severity gradient and relatively little quantitative information is available on intermediate-severity disturbance. On 20 April 2011, an EF1 tornado tracked 5 km through the Sipsey Wilderness in Alabama and resulted in a patchwork mosaic of disturbed areas. To analyze the effects of the intermediate-severity...

PREMISE OF THE STUDY: Molecular genetic evidence can help delineate taxa in species complexes that lack diagnostic morphological characters. Pinus ponderosa (Pinaceae; subsection Ponderosae ) is recognized as a problematic taxon: plastid phylogenies of exemplars were paraphyletic, and mitochondrial phylogeography suggested at least four subdivisions of P. ponderosa. These patterns have not been examined in the context of other Ponderosae species. We hypothesized that putative intraspecific subdivisions might each represent a separate taxon. METHODS: We genotyped six highly variable plastid...

Efforts to manage and eradicate invasive species can benefit from an improved understanding of the physiology, biology, and behavior of the target species, and ongoing efforts to eradicate the Asian longhorned beetle (Anoplophora glabripennis Motschulsky) highlight the roles this information may play. Here, we present a climate-driven phenology model for A. glabripennis that provides simulated life-tables for populations of individual beetles under variable climatic conditions that takes into account the variable number of instars beetles may undergo as larvae. Phenology parameters in the...

Studies of historical fire and vegetation conditions in dry conifer forests have demonstrated a high degree of heterogeneity across landscapes. However, there is a limit to the amount of inference that can be drawn from historical fire reconstructions. Contemporary "reference" landscapes may be able to provide information that is not available from historical reconstructions. In this study, we characterized variability in vegetation structure and composition across two Sierra Nevada landscapes with long-established fire restoration programs. We used tree, shrub, and surface fuel data from...

Premise of the study: Bromus tectorum (Poaceae) is an annual grass species that is invasive in many areas of the world but most especially in the U.S. Intermountain West. Single-nucleotide polymorphism (SNP) markers were developed for use in investigating the geospatial and ecological diversity of B. tectorum in the Intermountain West to better understand the mechanisms behind its successful invasion. Methods and Results: Normalized cDNA libraries from six diverse B. tectorum individuals were pooled and sequenced using 454 sequencing. Ninety-five SNP assays were developed for use on 96.96...

We assessed the nutritional strategy of true morels (genus Morchella) collected in 2003 and 2004 in Oregon and Alaska, 1 or 2 y after forest fires. We hypothesized that the patterns of stable isotopes (δ13C and δ15N) in the sporocarps would match those of saprotrophic fungi and that radiocarbon (Δ14C) analyses would indicate that Morchella was assimilating old carbon not current-year photosynthate. We compared radiocarbon and stable isotopes in Morchella with values from concurrently collected foliage, the ectomycorrhizal Geopyxis carbonaria (Alb. & Schwein.) Sacc., the saprotrophic...

Anoplophora glabripennis has a complex suite of mate-finding behaviors, the functions of which are not entirely understood. These behaviors are elicited by a number of factors, including visual and chemical cues. Chemical cues include a maleproduced volatile semiochemical acting as a long-range sex pheromone, a femaleproduced cuticular hydrocarbon blend serving as a sex-identification contact pheromone, and a recently identified female-produced trail sex pheromone that is followed by mate-seeking males. However, the sensory appendages and sensilla on these appendages used to detect the...

In southwest Montana, near the town of Three Forks, Milligan Creek cuts a small and seemingly mundane notch through dry limestone hills. Milligan Creek is unassuming and small enough to be effortlessly stepped over in most places. In fact, it flows underground for much of its 4-5 mile journey to the Jefferson River. Incredibly, forty-nine species of long-legged flies (Dolichopodidae) - fully 61% of the 81 species recorded to occur in Montana (Pollet et al. 2004) - have been collected along a very short stretch of this creek (see list below). These species were found during eight short...

Mountain pine beetle (Dendroctonus ponderosae) (MPB), a native insect to western North America, caused extensive tree mortality in pine ecosystems during a recent warm and dry period. More than 24 million acres were affected, including in the relatively low elevation lodgepole (Pinus contorta) and ponderosa (P. ponderosa) pines, and the high-elevation whitebark (P. albicaulis) and limber (P. flexilis) pines.

Progress is being made to build the science foundation for effective limber pine management. The power of repeated monitoring assessments now provides valuable condition trends for limber pine (Smith et al. 2013, Cleaver et al. 2015). In Canada, the proportion of dead limber pine increased from 2003-2004 and 2009 and WPBR infection increased from 33% to 43% putting some populations at risk for extirpation (Smith et al. 2013). In northern Colorado, Wyoming, and southeastern Montana 73% of the stands have been invaded by white pine blister rust (WPBR) with an average disease incidence of...