Mountain Pine Beetle Infestation Research Articles

Determination of the compositional change (1999–2006) in the pine forests of British Columbia due to mountain pine beetle infestation

The current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak in British Columbia and Alberta is the largest recorded forest pest infestation in Canadian history. We integrate a spatial hierarchy of mountain pine beetle and forest health monitoring data, collected between 1999 and 2006, with provincial forest inventory data, and generate three information products representing 2006 forest conditions in British Columbia: cumulative percentage of pine infested by mountain pine beetle, percentage of pine uninfested, and the change in the percentage of pine on the landscape. All input data were formatted to a standardized spatial representation (1 ha minimum mapping unit), with preference given to the most detailed monitoring data available at a given location for characterizing mountain pine beetle infestation conditions. The presence or absence of mountain pine beetle attack was validated using field data (n = 2054). The true positive rate for locations of red attack damage over all years was 92%. Classification of attack severity was validated using the Kruskal gamma statistic (gamma = 0.49). Error between the survey data and field data was explored using spatial autoregressive (SAR) models, which indicated that percentage pine and year of infestation were significant predictors of survey error at alpha = 0.05. Through the integration of forest inventory and infestation survey data, the total area of pine infested is estimated to be between 2.89 and 4.14 million hectares. The generated outputs add value to existing monitoring data and provide information to support management and modeling applications.

A NOVEL METHOD OF FITTING SPATIO‐TEMPORAL MODELS TO DATA, WITH APPLICATIONS TO THE DYNAMICS OF MOUNTAIN PINE BEETLES

Abstract We develop a modular landscape model for the mountain pine beetle (Dendroctonus ponderosae Hopkins) infestation of a stage‐structured forest of lodgepole pine (Pinus contorta Douglas). Beetle attack dynamics are modeled using response functions and beetle movement using dispersal kernels. This modeling technique yields four model candidates. These models allow discrimination between four broad possibilities at the landscape scale: whether or not beetles are subject to an Allee effect at the landscape scale and whether or not host selection is random or directed. We fit the models with aerial damage survey data to the Sawtooth National Recreation Area using estimating functions, which allows for more rapid and complete parameter determination. We then introduce a novel model selection procedure based on facial recognition technology to compliment traditional nonspatial selection metrics. Together with these we are able to select a best model and draw inferences regarding the behavior of the beetle in outbreak conditions.

Detecting spatial hot spots in landscape ecology

Hot spots are typically locations of abundant phenomena. In ecology, hot spots are often detected with a spatially global threshold, where a value for a given observation is compared with all values in a data set. When spatial relationships are important, spatially local definitions – those that compare the value for a given observation with locations in the vicinity, or the neighbourhood of the observation – provide a more explicit consideration of space. Here we outline spatial methods for hot spot detection: kernel estimation and local measures of spatial autocorrelation. To demonstrate these approaches, hot spots are detected in landscape level data on the magnitude of mountain pine beetle infestations. Using kernel estimators, we explore how selection of the neighbourhood size (τ) and hot spot threshold impact hot spot detection. We found that as τ increases, hot spots are larger and fewer; as the hot spot threshold increases, hot spots become larger and more plentiful and hot spots will reflect coarser scale spatial processes. The impact of spatial neighbourhood definitions on the delineation of hot spots identified with local measures of spatial autocorrelation was also investigated. In general, the larger the spatial neighbourhood used for analysis, the larger the area, or greater the number of areas, identified as hot spots.

Risk rating for mountain pine beetle infestation of lodgepole pine forests over large areas with ordinal regression modelling

The mountain pine beetle Dendroctonus ponderosae Hopkins is endemic to lodgepole pine, Pinus contorta var. latifolia Engelmann, forests in western Canada. However, the current beetle epidemic in this area highlights the challenges faced by forest managers tasked with prioritizing stands for mitigation activities such as salvage harvesting and direct control methods. In western Canada, the operational risk rating system for mountain pine beetle is based on biological knowledge gained from a rich legacy of stand-scale field studies. Due to the large spatial (millions of hectares affected) and temporal (over 10 years) extents of the current epidemic, new research into large-area mountain pine beetle processes has revealed further insights into the landscape-scale characteristics of beetle infested forests. In this paper, we evaluated the potential for this new knowledge to augment an established system for rating the short-term risk of tree mortality in a stand due to mountain pine beetle. New variables explored for utility in risk rating include direct shortwave radiation, site index, diameter at breast height, the temporal trends in local beetle populations, Biogeoclimatic Ecosystem Classification and beetle–host interaction variables. Proportional odds ordinal regression was used to develop a model for the Vanderhoof Forest District in west-central British Columbia. Prediction on independent data was assessed with the area under the receiver operator curve (AUC), indicating good discriminatory power (AUC = 0.84) for predicting levels of mountain pine beetle-caused pine mortality.

Erratum to “Perceptions of Ecological Risk Associated with Mountain Pine Beetle (Dendroctonus ponderosae) Infestations in Banff and Kootenay National Parks of Canada,” by Bonita L. McFarlane and David O. T. Witson, in Risk Analysis, 28(1), 2008

Erratum to “Perceptions of Ecological Risk Associated with Mountain Pine Beetle (<i>Dendroctonus ponderosae</i>) Infestations in Banff and Kootenay National Parks of Canada,” by Bonita L. McFarlane and David O. T. Witson, in <i>Risk Analysis, 28</i>(1), 2008

Effects of mountain pine beetle ( Dendroctonus ponderosae Hopkins) infestations on forest stand structure in the southern Canadian Rocky Mountains

Forests in the montane and lower subalpine ecoregions of the southern Canadian Rocky Mountains may have been more open and structurally diverse at the beginning of the 20th Century than today. Today, the area of mature Pinus contorta subsp. latifolia Dougl. forest that is conducive to mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) infestations, infrequent high severity fires, and herbivory appears to have increased in Banff and Kootenay National Parks. Based on a review of the literature, we hypothesised that MPB infestations increase forest stand structural diversity and tree species diversity. Stand structure parameters were investigated in mesic montane and lower subalpine stands approximately 15, 25, and 65 years after MPB outbreaks. Parameters measured were stand density (number of trees per ha), diameter at breast height, height class, species, age class distribution, and coarse woody debris mass. Influences of fire frequency, time since fire, and fire severity on these parameters were assessed to determine whether fire history had a confounding influence on stand structure. The Shannon–Wiener index indicated higher stand structural diversity 15 years but not 25 and 65 years after MPB infestations. MPB infestations led to general decreases within stands in the number of living trees, small diameter snags, and Pinus tree species and an increase within stands in the number of large diameter snags. Management that allows the occurrence of the natural fire regime of variable severity fires, in addition to some MPB infestations, would provide for more open and diverse stands. MPB infestations have some effects on stand structure that are similar to those of fire. Changes in stand structure resulting from recent declines in burning rates within Banff and Kootenay National Parks can be reversed to some extent by MPB infestations.

Spatial scaling of mountain pine beetle infestations

1. The relationship between occupancy and spatial contagion during the spread of eruptive and invasive species demands greater study, as it could lead to improved prediction of ecosystem damage. 2. We applied a recently developed model that links occupancy and its fractal dimension to model the spatial distribution of mountain pine beetle infestations in British Columbia, Canada. We showed that the distribution of infestation was scale-invariant in at least 24 out of 37 years (mostly in epidemic years), and presented some degree of scale-invariance in the rest. There was a general logarithmic relationship between fractal dimension and infestation occupancy. Based on the scale-invariance assumption, we further assessed the interrelationships for several landscape metrics, such as correlation length, maximum cluster size, total edge length and total number of clusters. 3. The scale-invariance assumption allows fitting the above metrics, and provides a framework to establish the scaling relationship between occupancy and spatial contagion. 4. We concluded that scale-invariance dominates the spread of mountain pine beetle. In this context, spatial aggregation can be predicted from occupancy, hence occupancy is the only variable one needs to know in order to predict the spatial distributions of populations. This supports the hypothesis that fractal dispersal kernels may be abundant among outbreaks of pests and invasive species.

Working together: a reciprocal wood flow arrangement to mitigate the economic impacts of natural disturbance

Summary This study investigates the regional economic impacts resulting from the current mountain pine beetle infestation in British Columbia, Canada, and proposes a mitigation strategy to reduce the negative impacts. The strategy consists of reducing the abrupt timber supply changes in an infested region through a reciprocal wood fl ow arrangement with an adjacent region less affected by the beetle. Two study areas facing different levels of beetle pressure are investigated: the Quesnel Timber Supply Area (high beetle pressure) and the combined Williams Lake/100 Mile House Timber Supply Area (low beetle pressure). A computable general equilibrium model is constructed for each region and is used to simulate the sensitivity of a suite of economic indicators to various timber supply scenarios for both regions. The results indicate that the negative economic impacts attributed to beetle damage could be reduced under a reciprocal wood fl ow agreement between the two regions. The degree to which the impacts are reduced in each region depends largely on assumptions about forest regeneration and growth and the terms of the reciprocal wood fl ow agreement.

Evaluation of a mature lodgepole pine stand's resistance to the current mountain pine beetle infestation after nitrogen fertilization

Research is currently under way in the Southern Interior Forest Region to determine whether nitrogen fertilization can be used to increase mature lodgepole pine trees' natural defences against the mountain pine beetle (MPB) and thereby reduce the impact of the mpb infestation in pine stands. In fall 2006, three nitrogen fertilizer treatments (0, 200, and 400 kg N/ha) were applied randomly to each of 10 plots in a 140-year-old fire-regenerated stand of mixed lodgepole pine, spruce, and true fir. In 2007, the stand was inoculated with two isolates of blue stain fungus and with local beetle microflora. A forest health survey helped determine the level of MPB within the stand before the plot centres were baited with pheromones. Early results show that the 400 kg N/ha treatment significantly increased nitrogen levels in pine phloem and needles. No significant differences were apparent in lesion length related to nitrogen treatment levels within each of the three fungal isolates. Measurements in 2008 will show whether MPB attack success varies among nitrogen treatments.

Perceptions of Ecological Risk Associated with Mountain Pine Beetle (Dendroctonus ponderosae) Infestations in Banff and Kootenay National Parks of Canada

Western Canada is experiencing an unprecedented outbreak of the mountain pine beetle (MPB). The MPB has the potential to impact some of Canada's national parks by affecting park ecosystems and the visitor experience. Controls have been initiated in some parks to lessen the impacts and to prevent the beetle from spreading beyond park boundaries. We examine the perception of ecological risk associated with MPB in two of Canada's national parks, the factors affecting perceptions of risk, and the influence of risk judgments on support for controlling MPB outbreaks in national parks. Data were collected using two studies of park visitors: a mail survey in 2003 and an onsite survey in 2005. The MPB was rated as posing a greater risk to the health and productivity of park ecosystems than anthropogenic hazards and other natural disturbance agents. Visitors who were familiar with MPB rated the ecological and visitor experience impacts as negative, unacceptable, and eliciting negative emotion. Knowledge and residency were the most consistent predictors of risk judgments. Of knowledge, risk, and demographic variables, only sex and risk to ecosystem domains influenced support for controlling the MPB in national parks. Implications for managing MPB in national parks, visitor education, and ecological integrity are discussed.

Mapping lodgepole pine stand structure susceptibility to mountain pine beetle attack across the western United States

Mountain pine beetle (MPB) outbreaks are important disturbances of forests in the western United States. Stand conditions influence the success of MPB attack through food availability, shelter, and effects on tree vigor and thus the ability of a tree to withstand MPB infestation. We estimated the contribution of stand structure to susceptibility to MPB-caused mortality in lodgepole pine forests by applying a model that incorporates stand age, stem density, and basal area by species. We utilized tree-level measurements across the western United States from the USDA Forest Service Resources Planning Act inventory database that permitted plot-level and county-level analysis. In the western United States, we found that stands were typically in age classes (60–120 years) and stem densities (>400 stem ha −1) that are highly susceptible. A third structural factor, the percentage of susceptible pine basal area within a stand (compared to all trees within that stand), typically reduced stand susceptibility across the region. However, when we considered the susceptibility of only the pine component instead of the entire stand, we found substantially increased susceptibility index values. Regional susceptibility was high (pine component susceptibility index >50, which has been related in past studies to 34% loss of stand basal area) for 2.8 Mha, or 46%, of lodgepole pine forest. Maps revealed variability among regions, with the highest susceptibility in the southern Rocky Mountains and the lowest in the coastal states. Our analysis provides useful information to land managers concerned with future forest ecosystem dynamics and forest susceptibility to MPB outbreak.

Snow accumulation and ablation in a beetle-killed pine stand in Northern Interior British Columbia

This preliminary study examined the impact of mountain pine beetle (Dendroctonus ponderosae) infestation and subsequent canopy mortality on ground snow accumulation and ablation in lodgepole pine (Pinus contorta) stands. During the winter of 2005–2006, meteorological and snow conditions were measured in three stands—dead, alive, and cleared—in Northern Interior British Columbia. Variations in measured snow conditions and meteorological data between stands were assessed. Data were used in an energy-balance model to calculate snow ablation in each stand and estimate effects on meltwater production. Results showed that the dead stand no longer behaved like an alive stand, but had not yet approached cleared stand conditions. Ablation rates in the dead stand remained similar to those in the alive stand, although accumulation was closer to that in the cleared stand. The combination of a low ablation rate and increased ground snow accumulation in the dead stand resulted in a lengthened period of snowpack disappearance. In the cleared stand, however, high ablation rates were sufficient to remove the thicker snowpack earlier than in the dead stand. A multi-year study is under way at a new research site to further quantify the relationship between beetle-kill and its effect on snowpack.

Predicted Fire Behavior in Selected Mountain Pine Beetle–Infested Lodgepole Pine

Abstract Using custom fuel models developed for use with Rothermel's surface fire spread model, we predicted and compared fire behavior in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stands with endemic, current epidemic, and postepidemic mountain pine beetle (Dendroctonus ponderosae Hopkins) populations using standardized sets of wind speeds and fuel moistures. We also compared our fire behavior results with those from standard fuel models. Results indicated that for surface fires both rates of fire spread and fireline intensities were higher in the current epidemic stands than in the endemic stands owing to increases in the amounts of fine surface fuels. In the postepidemic stands, rates of surface fire spread and fireline intensities were higher than in the endemic stands owing to decreased vegetative sheltering and its effect on mid-flame wind speed. Total heat release of surface fires, including postfrontal combustion, was also higher in the postepidemic stands owing to heavy accumulations of large diameter fuels. Crown fires were more likely to initiate in the postepidemic stands owing to greater fireline intensities and lower crown base heights. However, the critical rate of spread needed to sustain an active crown fire was higher in the postepidemic stands owing to decreased aerial fuel continuity. We suggest here that crown fire initiation in the current epidemic stands was also greater because of an abundance of dead aerial fuels; although this relationship is unclear.

A bird's eye view of small tenure holdings in British Columbia

This extension note provides a spatial description of the distribution of small, area-based tenures in the province of British Columbia. It summarizes important socio-economic and biophysical data, including the locations of small tenures. The unique management implications associated with such distribution are highlighted, such as multiple and often overlapping values, implications of mountain pine beetle infestations, climate change, forest restoration, and socio-economic constraints and opportunities.

Environmental characteristics of mountain pine beetle infestation hot spots

A combination of favourable temperatures and abundant host trees has resulted in a mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic over the majority of the lodgepole pine forests of British Columbia, Canada. Understanding temporal trends in the interactions between mountain pine beetle infestations and landscape characteristics can improve our understanding of beetle biology, inform modelling of future impacts, and support management. In this paper, we demonstrate a practical technique for characterizing spatial interactions between beetles and the environment. The locations with the highest-intensity infestations (hot spots) were identified using point data derived from annual helicopter-based surveys of beetle-infested pine, and a kernel density estimator. By examining the environmental characteristics associated with hot spots through time, an increased understanding of how the mountain pine beetle utilizes resources over large areas is generated. The effect of treatment on the persistence of hot spots is also explored. Results indicate that beetles intensely infest mature trees with a shift to younger trees over time. Hot-spot locations are most commonly associated with stands composed of 30–80% pine and almost always occur at elevations between 800 m and 1000 m. In the early years of an infestation, hot spots are typically found on warmer (south and west) aspects. As well, relative to non-treatment, any type of treatment reduces the persistence of hot spots the following year.

Arsenic Accumulation in Bark Beetles and Forest Birds Occupying Mountain Pine Beetle Infested Stands Treated with Monosodium Methanearsonate

The arsenic-based pesticide, monosodium methanearsonate (MSMA), is presently being evaluated for re-registration in Canada and the United States and has been widely used in British Columbia to help suppress Mountain Pine Beetle (MPB) outbreaks. We assessed the availability and exposure of MSMA to woodpeckers and other forest birds that may prey directly on contaminated bark beetles. Total arsenic residues in MPB from MSMA treated trees ranged from 1.3-700.2 microg g(-1) dw (geometric mean 42.0 microg g(-1)) with the metabolite monomethyl arsonic acid (MMAA) contributing 90-97% to the total arsenic extracted. Live adult and larval beetles were collected from treated trees and reached concentrations up to 327 microg g(-1) dw. MPBs from reference trees had significantly lower arsenic concentrations averaging 0.19 microg g(-1) dw. Woodpeckers foraged more heavily on MSMAtreesthat contained beetles with lower arsenic residues, suggesting those trees had reduced MSMAtranslocation and possibly greater live beetle broods. Blood samples from five species of woodpeckers and other forest passerines breeding within 1 km of MSMA stands contained elevated levels of total arsenic but with large individual variability (geometric mean = 0.18 microg g(-1) dw, range 0.02-2.20 microg g(-1). The results indicate that there is significant accumulation and transfer of organic arsenic within the food chain at levels that may present a toxicity risk to avian wildlife.

Assessing approaches to climate-change-related policy formulation in British Columbia's forest sector: The case of the mountain pine beetle epidemic

A growing literature considers how the forest management community will have to adapt to future climate change impacts. Recently in this journal, Spittlehouse and Stewart presented a framework for planning adaptive actions to address forest-related climate change issues. This paper expands on that framework by discussing five policy process approaches that might be used to implement such actions. The policy community approach outlines the complex configuration of policy actors. The policy network approach examines the relationships between those actors on particular issues. The advocacy coalition framework attempts to measure policy change by taking into account the competing policy-oriented belief structures. Agenda setting considers how issues get the attention of politicians. The punctuated equilibrium model attempts to explain how rapid change in government policy direction can alternate with long periods of stability. The authors conclude that understanding the policy process and how recommended policy changes will be realized is as important as identifying issues and the need for change. Examples from the application of these frameworks to British Columbia's mountain pine beetle infestation are highlighted throughout the paper.

Rating the susceptibility of forests to mountain pine beetle infestations: the impact of data

British Columbia is currently experiencing the largest mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic on record. The spatial extent of this infestation highlights the need for large-area forest management. We explore the use of three large-area data sets for implementing a stand-scale model of forest susceptibility that quantifies the probability of loss of pine basal area because of attack by the mountain pine beetle. Using these data sets, we investigate the impact of surrogate variables, which is necessary when variables required for the susceptibility model are not present in a data set. The impact of the source data information content on the susceptibility model output is also analyzed. Results indicate that the susceptibility model is sensitive to both surrogate variables and data sources and suggest that landscape level application of the susceptibility model, which was developed using stand-scale relationships, is problematic. Of particular concern is the use of photointerpreted data sets for model parameterization. The information content in photointerpreted data sets is much different than data on similar forest characteristics collected in the field and provides an inadequate substitute for implementing the forest susceptibility model.

Beetles, trees, and people: Regional economic impact sensitivity and policy considerations related to the mountain pine beetle infestation in British Columbia, Canada

This article investigates the regional economic impact sensitivity to the current mountain pine beetle infestation in five study areas of British Columbia, Canada, using a computable general equilibrium framework. Baseline general equilibrium economic databases are constructed for each region using a hybrid data collection approach involving primary and secondary sources. A computable general equilibrium model is constructed for each region and used to simulate the sensitivity of a suite of economic indicators to changes in forestry sector exports resulting from the impacts of mountain pine beetle on the available timber supply. The computable general equilibrium models constructed for each region provides an indication of economic vulnerability to the infestation and can assist decision-makers with the identification of policy considerations and priority areas for mitigation planning in response to the anticipated fluctuations in timber supply.

Integrating remotely sensed and ancillary data sources to characterize a mountain pine beetle infestation

The ongoing mountain pine beetle ( Dendroctonus ponderosae Hopkins) outbreak in British Columbia, Canada, has reached epidemic proportions, with the beetle expanding into geographic areas outside its known biological range. In this study, estimates of red attack damage were derived from a logistic regression model using multi-date Landsat imagery, and ancillary information including terrain attributes and solar radiation. The model estimates were found to be approximately 70% accurate using an independent set of beetle survey data as validation. This probability surface of red attack damage, along with forest inventory and terrain attributes, were used as inputs to decision tree analyses, in order to identify which forest attributes were associated with stands that had a greater likelihood of mountain pine beetle red attack damage. Three distinct decision tree models were developed, with each having a different set of input variables. The results of the analyses indicated that site index (an indicator of the quality of a forest site) and slope were the principal discriminators of the current mountain pine beetle attack, followed by basal area of pine dominated stands, and to a lesser extent, crown closure and stem density. The results suggest that indicators of site quality, particularly site index, could be a complementary addition to existing stand susceptibility rating models.