Estimating Extent of Mortality Associated with the Douglas-Fir Beetle in the Central and Northern Rockies

Data collected from Douglas-fir stands infected by the Douglas-fir beetle in Wyoming, Montana, Idaho, and Utah, were used to develop models to estimate amount of mortality in terms of basal area killed. Models were built using stepwise linear regression and regression tree approaches. Linear regression models using initial Douglas-fir basal area were built for all study sites but produce low precision estimates. Regression tree models using initial Douglas-fir basal area of stand density index or both were also build for all sites. Regression tree models provide a more realistic approach to estimate potential mortality by creating more homogenous mortality classes with reduced variance. The models developed provide land managers with a basis for determining the potential mortality should a Douglas-fir beetle outbreak develop

Anticoagulant selection in relation to the SAMe-TT2R2 score in patients with atrial fibrillation. the GLORIA-AF registry

Aim: The SAMe-TT2R2 score helps identify patients with atrial fibrillation (AF) likely to have poor anticoagulation control during anticoagulation with vitamin K antagonists (VKA) and those with scores >2 might be better managed with a target-specific oral anticoagulant (NOAC). We hypothesized that in clinical practice, VKAs may be prescribed less frequently to patients with AF and SAMe-TT2R2 scores >2 than to patients with lower scores. Methods and results: We analyzed the Phase III dataset of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), a large, global, prospective global registry of patients with newly diagnosed AF and ≥1 stroke risk factor. We compared baseline clinical characteristics and antithrombotic prescriptions to determine the probability of the VKA prescription among anticoagulated patients with the baseline SAMe-TT2R2 score >2 and ≤ 2. Among 17,465 anticoagulated patients with AF, 4,828 (27.6%) patients were prescribed VKA and 12,637 (72.4%) patients an NOAC: 11,884 (68.0%) patients had SAMe-TT2R2 scores 0-2 and 5,581 (32.0%) patients had scores >2. The proportion of patients prescribed VKA was 28.0% among patients with SAMe-TT2R2 scores >2 and 27.5% in those with scores ≤2. Conclusions: The lack of a clear association between the SAMe-TT2R2 score and anticoagulant selection may be attributed to the relative efficacy and safety profiles between NOACs and VKAs as well as to the absence of trial evidence that an SAMe-TT2R2-guided strategy for the selection of the type of anticoagulation in NVAF patients has an impact on clinical outcomes of efficacy and safety. The latter hypothesis is currently being tested in a randomized controlled trial. Clinical trial registration: URL: https://www.clinicaltrials.gov//Unique identifier: NCT01937377, NCT01468701, and NCT01671007

Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

Background and purpose: Prospectively collected data comparing the safety and effectiveness of individual non-vitamin K antagonists (NOACs) are lacking. Our objective was to directly compare the effectiveness and safety of NOACs in patients with newly diagnosed atrial fibrillation (AF). Methods: In GLORIA-AF, a large, prospective, global registry program, consecutive patients with newly diagnosed AF were followed for 3 years. The comparative analyses for (1) dabigatran vs rivaroxaban or apixaban and (2) rivaroxaban vs apixaban were performed on propensity score (PS)-matched patient sets. Proportional hazards regression was used to estimate hazard ratios (HRs) for outcomes of interest. Results: The GLORIA-AF Phase III registry enrolled 21,300 patients between January 2014 and December 2016. Of these, 3839 were prescribed dabigatran, 4015 rivaroxaban and 4505 apixaban, with median ages of 71.0, 71.0, and 73.0 years, respectively. In the PS-matched set, the adjusted HRs and 95% confidence intervals (CIs) for dabigatran vs rivaroxaban were, for stroke: 1.27 (0.79–2.03), major bleeding 0.59 (0.40–0.88), myocardial infarction 0.68 (0.40–1.16), and all-cause death 0.86 (0.67–1.10). For the comparison of dabigatran vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 1.16 (0.76–1.78), myocardial infarction 0.84 (0.48–1.46), major bleeding 0.98 (0.63–1.52) and all-cause death 1.01 (0.79–1.29). For the comparison of rivaroxaban vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 0.78 (0.52–1.19), myocardial infarction 0.96 (0.63–1.45), major bleeding 1.54 (1.14–2.08), and all-cause death 0.97 (0.80–1.19). Conclusions: Patients treated with dabigatran had a 41% lower risk of major bleeding compared with rivaroxaban, but similar risks of stroke, MI, and death. Relative to apixaban, patients treated with dabigatran had similar risks of stroke, major bleeding, MI, and death. Rivaroxaban relative to apixaban had increased risk for major bleeding, but similar risks for stroke, MI, and death. Registration: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01468701, NCT01671007. Date of registration: September 2013

Probability of Infestation and Extent of Mortality Associated with the Douglas-fir Beetle in the Colorado Front Range

Infested and uninfested areas within Douglas fir, Pseudotsuga menziesii Ž . Mirb. Franco, stands affected by the Douglas-fir beetle, Dendroctonus pseudotsugae Hopk. were sampled in the Colorado Front Range, CO. Classification tree models were built to predict probabilities of infestation. Regression trees and linear regression analysis were used to model amount of tree mortality in terms of basal area killed in infested stands. Classification trees had cross-validation estimates of classification accuracy ranging from 0.55 to 0.63. The data suggests that Douglas-fir beetle-attacked stands contain a high percentage of the basal area represented by Douglas-fir, high tree densities, and poor growth during the last 5 years prior to attack. Trees prone to attack by the Douglas-fir beetle within infested points also exhibited reduced growth rates. Tree and linear regression analysis indicate that initial amount of Douglas-fir basal area can be used as a predictor variable for the amount of basal area affecte

Within-Stand Spatial Distribution of Tree Mortality Caused by the Douglas-Fir Beetle (Coleoptera : Scolytidae)

The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, causes considerable mortality in Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, forests. Within-stand distribution of mortality was examined in affected stands using geostatistical techniques. A 10 x 10 m grid was established in two 4-ha study sites. Live and beetle-killed host basal area was measured at each node. In a 16-ha stand, a variable-resolution grid was established and the same information collected. The relationship between Douglas-fir basal area and Douglas-fir basal area killed was examined using non-spatially explicit and spatially explicit linear regression models. A positive linear relationship was observed between the variables. Significant spatially explicit models suggest that the relationship is also true at fine scales. Relative variograms were constructed for Douglas-fir basal area before and after the Douglas-fir beetle outbreaks. For the 4-ha sites, increased spatial dependency in the distribution of Douglas-fir basal area was observed as a result of the Douglas-fir beetle outbreak. For the 16-ha site, kriging was used to estimate live Douglas-fir basal area before and after the outbreak to a 10-m resolution and the stand rated for potential mortality illustrating the potential applicability of geostatistical techniques to rating a stand for potential mortality. Cross-validation analysis indicated that although the potential exists for large estimation errors, the majority of the estimates were within acceptable ranges. The study suggests that geostatistical approaches may be suitable to extend our understanding bark beetle ecology and improving the application of extent of mortality models

Variables Associated With the Occurrence of Ips Beetles, Red Turpentine Beetle and Wood Borers in Live and Dead Ponderosa Pines with Post-fire Injury

Recently, wildfires and prescribed burning have become more frequent in conifer forests of western North America. Most studies examining the impacts of insects on trees with post‐fire injury have focused on contributions to tree mortality. Few studies have examined fire‐caused injuries to estimate the probability of attack by insects. Scant data quantifying insect associations with one another, or with live and dead fire‐injured trees, are available. We examined live and dead trees with varying levels of fire injury in wildfires in Colorado, Montana, Arizona and the Black Hills aiming to determine fire injury associated with insect infestation, co‐occurrence between insects and insect association with live and dead fire‐injured trees. Bole scorch height estimated the likelihood of attack by Ips spp. Diameter at breast height, bole scorch height and crown scorch height estimated the likelihood of attack by Dendroctonus valens LeConte. Diameter at breast height and bole scorch height estimated the likelihood of attack by wood borers. Ips spp., Dendroctonus valens and wood borers were associated with one another. Ips spp. beetles and wood borers were associated with dead fire‐injured trees, whereas D. valens was often associated with live fire‐injured trees. Focusing on certain fire‐caused injuries may identify trees targeted by Ips spp. beetles, Dendroctonus valens and wood borers

Evaluating Potential Fire Behavior in Lodgepole Pine-Dominated Forests after a Mountain Pine Beetle Epidemic in North-Central Colorado

A mountain pine beetle outbreak in Colorado lodgepole pine forests has altered stand and fuel characteristics that affect potential fire behavior. Using the Fire and Fuels Extension to the Forest Vegetation Simulator, potential fire behavior was modeled for uninfested and mountain pine beetle-affected plots 7 years after outbreak initiation and 10 and 80% projected tree fall using measured and projected fuel and stand characteristics. Under 90th percentile weather conditions, uninfested plots exhibited proportionally more crown fire than infested plots. Plots predicted to have crown fire were composed mainly of nonhost conifer species and had a lower and more continuous canopy than infested plots. Where surface fire was predicted to occur, live lodgepole pine was the only conifer present, and plots had significantly lower tree mortality from fire than plots predicted to have crown fire. Mountain pine beetle-induced changes in stand and fuel characteristics resulted in increased intensity of surface fire behavior. Furthermore, with 80% infested tree fall, potential smoke production was predicted to be higher. Tree species composition of stands pre and postbark beetle outbreak is important when identifying mountain pine beetle-caused changes to potential fire behavior

Stand Characteristics and Downed Woody Debris Accumulations Associated with a Mountain Pine Beetle (Dendroctonus ponderosae Hopkins) Outbreak in Colorado

Lodgepole pine (Pinus contorta Dougl. ex Loud.)-dominated ecosystems in north-central Colorado are undergoing rapid and drastic changes associated with overstory tree mortality from a current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak. To characterize stand characteristics and downed woody debris loads during the first 7 years of the outbreak, 221 plots (0.02 ha) were randomly established in infested and uninfested stands distributed across the Arapaho National Forest, Colorado. Mountain pine beetle initially attacked stands with higher lodgepole pine basal area, and lower density and basal area of Engelmann spruce (Picea engelmannii [Parry]), and subalpine fir (Abies lasiocarpa (Hook.) Nutt. var. lasiocarpa) compared to uninfested plots. Mountain pine beetle-affected stands had reduced total and lodgepole pine stocking and quadratic mean diameter. The density and basal area of live overstory lodgepole declined by 62% and 71% in infested plots, respectively. The mean diameter of live lodgepole pine was 53% lower than pre-outbreak in infested plots. Downed woody debris loads did not differ between uninfested plots and plots currently infested at the time of sampling to 3 or 4–7 years after initial infestation, but the projected downed coarse wood accumulations when 80% of the mountain pine beetle-killed trees fall indicated a fourfold increase. Depth of the litter layer and maximum height of grass and herbaceous vegetation were greater 4–7 years after initial infestation compared to uninfested plots, though understory plant percent cover was not different. Seedling and sapling density of all species combined was higher in uninfested plots but there was no difference between infested and uninfested plots for lodgepole pine alone. For trees ≥2.5 cm in diameter at breast height, the density of live lodgepole pine trees in mountain pine beetle-affected stands was higher than Engelmann spruce, subalpine fir, and aspen, (Populus tremuloides Michx.), in diameter classes comprised of trees from 2.5 cm to 30 cm in diameter, suggesting that lodgepole pine will remain as a dominant overstory tree after the bark beetle outbreak

Relationships Between Moisture, Chemistry, and ignition of Pinus contorta Needles During the Early Stages of Mountain Pine Beetle Attack

Very little is known about how foliar moisture and chemistry change after a mountain pine beetle attack and even less is known about how these intrinsic foliar characteristics alter foliage ignitability. Here, we examine the fuel characteristics and ignition potential of Pinus contorta (lodgepole pine) foliage during the early stages of a mountain pine beetle attack. Foliar samples were taken periodically from multiple trees identified as green (healthy, unattacked), recently attacked, or red (dead). The fuel moisture con- tent, chemical composition, and time to ignition of needles from each attack category were quantified. Foliar moisture contents varied by an order of magnitude between the attack categories and were lowest for red needles (�12% on average), highest for green needles (�109% on average), and most variable for needles of recently attacked trees. Dry matter proportions of fiber in the needles of attacked and red trees were nearly twice that of green needles. Starch and sugar levels were much lower in the needles of attacked and red trees than green trees. Crude fat contents also differed between the attack categories. Time to ignition was strongly related to time since beetle attack. Ignition times varied from as little as 11 s for red needles to 41 s for green needles. A combined model of foliar moisture content, fiber, and crude fat explained 92% of the variation in the foliar time to ignition. Results show that decreased mois- ture contents and changes in foliar chemistry increase the foliar flammability of mountain pine beetle- attacked trees. This suggests that less heat would be required to ignite the foliage of attacked trees and thus crown fire potential may be higher in attacked stands as long as foliage is retained on the tree. Published by Elsevier B.V