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In Colorado and southern Wyoming, mountain pine beetle (MPB) has affected over 1.6 million ha of predominantly lodgepole pine forests, raising concerns about effects of MPB-caused mortality on subsequent wildfire risk and behavior. Using empirical data we modeled potential fire behavior across a gradient of wind speeds and moisture scenarios in Green stands compared three stages since MPB attack (Red [1-3 yrs], Grey [4-10 yrs], and Old-MPB [∼30 yrs]). MPB killed 50% of the trees and 70% of the basal area in Red and Grey stages. Across moisture scenarios, canopy fuel moisture was one-third lower in Red and Grey stages compared to the Green stage, making active crown fire possible at lower wind speeds and less extreme moisture conditions. More-open canopies and high loads of large surface fuels due to treefall in Grey and Old-MPB stages significantly increased surface fireline intensities, facilitating active crown fire at lower wind speeds (>30-55 km/hr) across all moisture scenarios. Not accounting for low foliar moistures in Red and Grey stages, and large surface fuels in Grey and Old-MPB stages, underestimates the occurrence of active crown fire. Under extreme burning conditions, minimum wind speeds for active crown fire were 25-35 km/hr lower for Red, Grey and Old-MPB stands compared to Green. However, if transition to crown fire occurs (outside the stand, or within the stand via ladder fuels or wind gusts >65 km/hr), active crown fire would be sustained at similar wind speeds, suggesting observed fire behavior may not be qualitatively different among MPB stages under extreme burning conditions. Overall, the risk (probability) of active crown fire appears elevated in MPB-affected stands, but the predominant fire hazard (crown fire) is similar across MPB stages and is characteristic of lodgepole pine forests where extremely dry, gusty weather conditions are key factors in determining fire behavior.

Geleophysic dysplasia (GD) is characterized by short stature, brachydactyly, joint limitations, a distinctive facial appearance, as well as cardiac and respiratory dysfunction that can be life-threatening. GD is caused by pathogenic variants in the ADAMTSL2 , FBN1 , or LTBP3 genes. While dermal fibroblasts derived from affected individuals have shown poor organization of the extracellular matrix (ECM), it remains elusive how the disorganized ECM contributes to GD pathogenesis. To understand the molecular mechanisms in GD, we isolated and characterized primary human dermal fibroblasts from affected individuals with ADAMTSL2 and FBN1 variants. We found that the secretion of ECM proteins including ADAMTSL2, FBN1, and Fibronectin were impaired in GD fibroblasts. Increased cell migration was observed in GD fibroblasts carrying ADAMTSL2 or FBN1 variants, which was associated with up-regulation of MMP-1 and MMP-14, two proteases related to cell mobility. The enhanced cell migration and up-regulation of MMP-1 and MMP-14 were corroborated in mouse primary dermal fibroblasts carrying pathogenic variants in Adamtsl2 and in lung and heart tissues from Adamtsl2 - knockout mice. A pan MMP inhibitor, GM6001, inhibited the migration of GD fibroblasts. Overall, our results suggest that MMP-1/-14 up-regulation play a role in the development of GD and may be utilized as a treatment target.

In recent years, the mountain pine beetle, Dendroctonus ponderosae Hopkins, has impacted >8.9 million hectares of forests in the western United States. During endemic populations, trees weakened by other agents are often colonized by D. ponderosae but may be difficult to detect due to their scarcity. Once populations reach incipient levels, tree defenses are often insufficient in deterring mass attacks, and populations rapidly increase causing substantial levels of tree mortality under certain circumstances. There are two general approaches for reducing the negative impacts of D. ponderosae on forests. Direct control involves short-term tactics designed to address current infestations by manipulating beetle populations and includes the use of fire, insecticides, semiochemicals, sanitation harvests, or combinations of these treatments. Indirect control is preventive and designed to reduce the probability and severity of future infestations by manipulating stand, forest and/or landscape conditions by reducing the number of susceptible host trees through thinning, prescribed burning, and/or alterations of age classes and species composition. We review tree, stand, and landscape factors associated with D. ponderosae infestations and analyze the effectiveness of treatments for preventing and mitigating undesirable levels of tree mortality. We describe the current state of our knowledge and identify gaps for making informed management decisions.

Abstract The mountain pine beetle (MPB) (Dendroctonus ponderosae) is one of the most prevalent disturbance agents in western conifer forests. It utilizes various species of pines (Pinus spp.) as host trees. Eruptive populations can cause extensive tree mortality. Since the late 1990s, extensive outbreaks have occurred from the southern Rockies to British Columbia. In Colorado, lodgepole pine (P. contorta) forests have been the most affected. Since 1996, about 3.4 million acres of lodgepole and ponderosa pine (P. ponderosa) forests have exhibited MPB-caused tree mortality. A large portion of the larger diameter trees have been killed with significant reductions in basal areas and tree densities. Tree mortality has impacted many forest ecosystem services including fiber production, hydrology, nutrient cycling, wildlife habitat, property values, and recreation. In this article, we examine and summarize some of what we have learned about MPB impacts from observations and research over the past two decades in Colorado.

Until it was discovered in Boulder, Colorado in 2013, the invaded range of the emerald ash borer, Agrilus planipennis , in the Western Hemisphere was entirely limited to natural and urban forests of eastern North America. Subsequently, this species has expanded its range through much of the Colorado Front Range region, utilizing non-native ash, Fraxinus spp. These host trees are widely planted there in urban settings but natural forests containing ash are lacking in the region. Here we use survey data to quantify emerald ash borer regional spread across the Colorado Front Range as well as its local spread in the city of Longmont, Colorado. Across the region, spread rate was estimated at 3.9 km/yr, but within Longmont the rate was only 0.25 km/yr. These rates of spread are lower than what has been reported from comparable spatial scales in eastern North America and the slower spread may reflect reduced host resource availability, successful implementation of management, or differences in environmental conditions.

[...]aggregation pheromones are produced to attract other D. ponderosae to attack the tree in a process referred to as \"mass attack.\" [...]utilization of beetle-killed trees for biomass and energy production has become a topic of interest for private and public land managers but its processing is still in its infancy, and technology is being developed.

Research Highlights: The biology of mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, in Colorado’s lodgepole pine forests exhibits similarities and differences to other parts of its range. Brood emergence was not influenced by stand density nor related to tree diameter. The probability of individual tree attack is influenced by stocking and tree size. Findings have implications for understanding MPB as a disturbance agent and for developing management strategies. Background and Objectives: MPB causes extensive tree mortality of lodgepole pine, Pinus contorta Douglas ex Loudon, across the western US and Canada and is probably the most studied bark beetle in North America. However, most of the current knowledge on the biology and ecology of MPB in lodgepole pine comes from the Intermountain Region of the US and western Canada. Little information is available from Colorado. This is the first study addressing effects of stand stocking levels on the biology of MPB and quantifying phloem consumption. In addition, although data are available on the conditions that foster stand infestation, this is the first study estimating the probability of individual tree attack among stands of known different stocking. Materials and Methods: Studies were conducted in managed lodgepole pine stands in Colorado. Unbaited traps were used to monitor MPB flight across stands of different densities. Cages were used to monitor emergence and bark samples to determine attack densities, and phloem consumption in trees growing under different stocking. Beetle collections were used to determine emergence across the growing season. Tree mortality data from plots of different densities were used to examine the probability of individual tree infestation. Results: More beetles were caught flying through higher density stands. More attacks were observed in lower stocking stands but there were no differences in the number of insects emerging nor phloem consumption. There was no relationship between tree size and beetle emergence. Peak flight occurred in early to mid-August and only one peak of beetle emergence occurred. The probability of tree attack was influenced by stand stocking and tree diameter. Conclusions: In general, aspects of the biology of MPB in Colorado exhibit similarities and differences with other regions. The data suggest the need to more closely examine how MPB functions in stands of different stocking and how the distribution of tree sizes influence the probability of infestation and extent of mortality in stands. Biological characteristics of MPB in Colorado need further examination, particularly as climate change continues to manifest. Baseline information will be critical to refine management approaches, and extend the understanding of how MPB contributes to shape forest composition and structure in Colorado.

The mountain pine beetle (MPB) (Dendroctonus ponderosae) is a bark beetle that attacks and kills ponderosa pine (Pinus ponderosa), among other pine species throughout the western conifer forests of the United States and Canada, particularly in dense stands comprising large trees. There is information on the stand conditions that the insect prefers. However, there is a paucity of information on how small-scale variation in stand conditions influences the distribution of tree mortality within a stand. I examined the small-scale distribution of ponderosa pine basal area pre- and post a mountain pine beetle infestation, and used geostatistical modeling to relate the spatial distribution of the host to subsequent MPB-caused tree mortality. Results indicated increased mortality in the denser parts of the stand. Previous land management has changed historically open low-elevation ponderosa pine stands with aggregated tree distribution into dense stands that are susceptible to mountain pine beetles and intense fires. Current restoration efforts are aimed at reducing tree density and leaving clumps of trees, which are more similar to historical conditions. The residual clumps, however, may be susceptible to mountain pine beetle populations. Land managers will want to be cognizant of how mountain pine beetles will respond to restoration treatments, so as to prevent and mitigate tree mortality that could negate restoration efforts.

Comprehensive and accurate detection of variants from whole-genome sequencing (WGS) is a strong prerequisite for translational genomic medicine; however, low concordance between analytic pipelines is an outstanding challenge. We processed a European and an African WGS samples with 70 analytic pipelines comprising the combination of 7 short-read aligners and 10 variant calling algorithms (VCAs), and observed remarkable differences in the number of variants called by different pipelines (max/min ratio: 1.3~3.4). The similarity between variant call sets was more closely determined by VCAs rather than by short-read aligners. Remarkably, reported minor allele frequency had a substantial effect on concordance between pipelines (concordance rate ratio: 0.11~0.92; Wald tests, P  < 0.001), entailing more discordant results for rare and novel variants. We compared the performance of analytic pipelines and pipeline ensembles using gold-standard variant call sets and the catalog of variants from the 1000 Genomes Project. Notably, a single pipeline using BWA-MEM and GATK-HaplotypeCaller performed comparable to the pipeline ensembles for ‘callable’ regions (~97%) of the human reference genome. While a single pipeline is capable of analyzing common variants in most genomic regions, our findings demonstrated the limitations and challenges in analyzing rare or novel variants, especially for non-European genomes.

Climatic changes are predicted to significantly affect the frequency and severity of disturbances that shape forest ecosystems. We provide a synthesis of climate change effects on native bark beetles, important mortality agents of conifers in western North America. Because of differences in temperature-dependent life-history strategies, including cold-induced mortality and developmental timing, responses to warming will differ among and within bark beetle species. The success of bark beetle populations will also be influenced indirectly by the effects of climate on community associates and host-tree vigor, although little information is available to quantify these relationships. We used available population models and climate forecasts to explore the responses of two eruptive bark beetle species. Based on projected warming, increases in thermal regimes conducive to population success are predicted for Dendroctonus rufipennis (Kirby) and Dendroctonus ponderosae Hopkins, although there is considerable spatial and temporal variability. These predictions from population models suggest a movement of temperature suitability to higher latitudes and elevations and identify regions with a high potential for bark beetle outbreaks and associated tree mortality in the coming century.