The Forest Forum was one in the series of annual research forums that the Mountain Pine Beetle Ecology Program hosts in Edmonton, Alberta. It was held April 24 and 25, 2018, at the University of Alberta. The forum is presented by the fRI Research Mountain Pine Beetle Ecology Program, TRIA-Net, and the Canadian Institute of Forestry and sponsored by Alberta Innovates.
This event has been designed to provide an opportunity for attendees to hear from leading scientists, forest practitioners, community leaders and government executives. Presentations will set the stage for important discussions focused on our forest ecosystem and threats to it. We will also hear and discuss current thinking about new constructs for management that attempt to minimize risks in maintaining ecological sustainability. Our goal in hosting the 2018 Forest Forum will be realized if you leave with an appreciation of the threats and risks facing Alberta’s forests, the science that is available to support decisions and a commitment to a collective role in maintaining the continued flow of ecological services, and ensuring industries and communities remain vibrant and sustainable.
Keynote: Canada’s transitioning forests in the midst of threats and climate change
by Mark Johnston
Abstract: Canada’s western boreal forest is under threat from several sources: fire, insects and disease, drought and human disturbance, all potentially intensified by climate change. This presentation will provide a high-level overview of these threats and how climate change may affect them and the interactions among them. I will then provide some ideas about how climate change risks can be assessed using tools specific to Canadian Sustainable Forest Management (SFM), and will show how climate change considerations can be brought into SFM and become part of day-to-day planning and decision making.
Forest pests and damaging agents under climate change and Alberta’s program adaptations
by Erica Samis
Abstract: Presence of forest pests and the severity of damage caused has been monitored in Alberta for many years by federal and provincial agencies. Cyclic trends and typical pest disturbance patterns can be discerned from the data. Going forward, the cycles and distribution of these same pests are expected to change under climate change. While change is expected, it is unclear which pests may become important in the future. Native forest pests may expand their historic ranges and the severity of the damage caused to Alberta’s forests may increase. Secondary pests that attack weak or dying trees may become primary pests that can cause mortality. As climate changes, an increased number of invasive forest pests may become established if introductions occur. Alberta Forest Health and Adaptation is answering the call for action by taking proactive steps to understand the potential changes in biotic pests that threaten Alberta’s forests.
Chemical ecology of mountain pine beetles: chemical and anatomical defenses
by Nadir Erbilgin and Violet Zhao
Abstract: Host tree colonization by mountain pine beetle involves several stages from host selection to aggregation, establishment (mating and reproduction), and (offspring) dispersal. All these stages are closely linked to the host tree chemistry such as monoterpenes in the tree resin. During the initial phase of host selection, beetles respond to visual or chemical cues, and enter or leave the host based on short-range chemical and tactile stimuli. If the host is acceptable, the beetles bore through the outer bark, excavate a nuptial chamber in the phloem and produce aggregation pheromones that attract conspecifics. After mating, the female excavates egg galleries and deposits eggs along the gallery walls. The developing larvae feed on phloem and/or fungi in the larval galleries. The full development from egg to adult takes a year. In our presentation, we will explain the functional roles of these chemicals on the beetle behaviours that govern host acceptance for mating, oviposition, larval development, and dispersal. Besides defense chemicals, trees also rely on anatomical defenses against mountain pine beetle. Such as the xylem axial resin duct characteristics can be closely linked to resin execution, along with tree chemical defenses. We will provide the roles of resin duct-based defenses in the survival of residual trees during beetle outbreak and post-beetle outbreak phase.
MPBSpread: modelling the spread of the mountain pine beetle through novel pine forests
by Allan Carroll
Abstract: MPBSpread is a spatially explicit cellular automata model that simulates mountain pine beetle (MPB) spread through application of a series of rules that describe beetle behavior in relation to (i) infestation and host characteristics, and (ii) application of beetle control tactics. Using MPBSpread, we assessed the efficacy of efforts by the Government of Alberta to slow the eastward spread of MPB. Empirical data on area colonized agreed well with MPBSpread predictions under the ongoing “slow-the-spread” strategy. Area colonized by MPB was almost always lower under slow-the-spread than a “do nothing” scenario, and separation between the two scenarios increased over time such that by 2018, slow-the-spread reduced the area colonized to roughly 70% of that predicted to have occurred without control efforts. Area colonized was particularly sensitive to the efficacy of early detection and eradication, and the amount of level 1 control (single tree treatments), but not level 2 control (clear cut harvesting).
Population state-dependent invasion potential of the mountain pine beetle in Alberta
by Stan Pokorny for Jordan Burke
Abstract: Global climate change has led to the migration of many taxa beyond their historic range. In North American forests, bark beetles have proven particularly destructive, with some species expanding their range into previously unavailable forests. The mountain pine beetle (Dendroctonus ponderosae) is of most concern, as it has expanded well beyond historic limits and outbreaks have destroyed millions of hectares of pine forests in the west. Mountain pine beetles are now found in the boreal forest of Alberta, Canada, infesting the novel host jack pine (Pinus banksiana). Evidence suggests that high-density outbreak populations of the beetle should perform better in jack pines. However, widespread outbreaks have not been observed. Here, we conducted a field experiment to examine the role of competition in mountain pine beetle endemic population-phase conditions throughout the current range in western Canada. Mortality was induced in lodgepole pine (P. contorta latifolia) and jack pine trees, and woodboring beetle (Coleoptera: Cerambycidae and Buprestidae) and subcortical fungi activity was measured. Jack pines were found to be attacked and colonized at a greater rate and magnitude, and earlier in the mortality process. We conclude that the invasion potential of mountain pine beetle in jack pine is context-dependent, and sub-outbreak populations are unlikely to persist long-term due to a lack of coevolution with these competitors
MPB Winter Survival: How low can they go?
by Katherine Bleiker
Abstract: Given the presence of a suitable food source, temperature likely has the largest overall impact on mountain pine beetle’s (MPB) distribution and population dynamics. Winter is usually the largest single source of mortality even in benign climates like southern British Columbia. Weather during the growing season affects development and MPB needs to maintain an adaptive seasonality – a synchronous one-year life cycle with the most hardy life stage entering winter – to be successful. This presentation reports the results of research on MPB cold tolerance and seasonality (developmental regulation) and what it means for MPB spread east in Canada. The ultimate goal of the research is to improve predictions of annual population trends based on annual weather; and provide the necessary empirical data to improve climatic suitability and spread models to identify areas regions at risk and the potential for eastward spread in Canada.
Rehabilitation of beetle-killed stands by improving pine seedling performance with mycorrhizal fungi
by Justine Karst
Abstract: Ectomycorrhizal fungi are critical for pine survival and performance, and species of fungi vary in benefits conferred to host trees. Our previous research demonstrates that fungal communities in soils change following beetle-induced tree mortality, with consequences for pine seedling survival and performance. While novel, this previous research had several limitations: 1) it covered a limited spatial scale, 2) it was correlative, and 3) it did not account for changes in fungal communities due to disturbance per se. Our next stage of research addresses these limitations to inform strategies to triage beetle-killed stands for rehabilitation. Specifically, we investigate the response of fungal communities to beetle-induced tree mortality at a regional scale with considerable sampling depth and landscape coverage. Moreover, we experimentally test whether inoculation by mycorrhizal fungi differing in origin influences performance of seedlings planted into beetle-killed stands. And finally, we compare the community composition of fungi in beetle-killed stands to that found in response to disturbances typical in the boreal forest: fire and harvesting.
Introduction to TRIA-Net
by Janice Cooke
Abstract: Over the course of nearly 20 years, we have witnessed the spread of mountain pine beetle into regions where this devastating forest insect pest has not been documented in contemporary times. These novel habitats differ markedly from historic mountain pine beetle habitats. Decision support systems that rely on the ability to forecast risk of mountain pine beetle attack are a cornerstone of spread control programmes, but the efficacy of these tools is limited by our lack of understanding of how the differing conditions in these novel habitats might impact mountain pine beetle population dynamics. Over the last decade, members of the Tria consortium of researchers have undertaken novel molecular, genetic and ecological studies to shed new light on mountain pine beetle and the fungi that they carry, the pine hosts that they attack, and beetle-pine interactions in these novel habitats. Different aspects of these studies have been used directly or indirectly to develop several new models of mountain pine beetle spread risk and stand level risk. Researchers have also looked at economic and socioeconomic impacts of mountain pine beetle on communities, forests products and ecosystem services. Findings are provided in real time to stakeholders in Alberta and other jurisdictions, who have used these new insights to guide policy and management decisions.
Theme 1: Chemical ecology of MPB, hosts, and symbionts - management implications
by Dezene Huber
Abstract: Our TRIA-Net work and its predecessor project have now been funded for about ten years. During that time we have been able to investigate the genomics of the mountain pine beetle system – host, insect, and fungi – in substantial depth and detail. Our work has provided the first ever bark beetle genome. We have discovered new things about how the insect colonizes its hosts, how the hosts respond to the insect invasion, and how the insects survive and often thrive in the face of those defenses and a hostile environment. Above all we have had the opportunity to train a large number of talented new scientists. We now look forward to continuing our work in new ways, and to seeing how others – including many of our trainees – carry on this research both on the mountain pine beetle system and in other emerging areas of Canada’s natural resources sector.
Theme 2: Population genomics of MPB, hosts, and symbionts – management implications
by David Coltman
Abstract: Population genomics – the use of high density genetic markers to compare populations - has revealed many new biological insights into the MPB system that may improve forestry management outcomes. We have shown that beetle, fungal and pine populations are genetically structured, show distinct signatures of spatial and environmental correlation, and gene by gene associations among taxa. These findings have two important management implications. First, as it suggests that populations are locally co-adapted, not all populations are biologically equivalent, particularly along outbreak expansion axes. Second, the spatial analysis of genetic signatures provides a better understanding of outbreak dynamics. For example, analysis of beetles in Jasper shows that they are a mixed stock of northern and southern genetic backgrounds. If outbreaks extend eastward from Jasper, we can now identify the origin of new outbreak populations and more precisely monitor outbreak dynamics. For a second example, we now have mapped the lodgepole and jack pine hybrid zone in Alberta, a potential bridge between outbreaking populations in lodgepole and the vast naïve jack pine range, at a much finer resolution. Our new hybrid map reveals a second potential bridge in the northern hybrid zone between lodgepole and jack pine in the Yukon and NWT.
Theme 3: Dynamics of mountain pine beetle populations in novel habitats: implications for management
by Allan Carroll
Abstract: Within its native range, the eruptive population dynamics of the mountain pine beetle (MPB) are a result of its complex interactions with a distinct suite of density-dependent and density-independent agents. The potential for MPB to erupt and spread in recently invaded pine forests east of the Rocky Mountains is unknown. This presentation will summarize the results of a five-year-long investigation initiated to determine (i) if MPB can exist in the endemic phase in novel pine habitats, and if so, what density of beetles is required to transition to the epidemic phase, and (ii) how dispersal/spread of epidemic MPB in novel habitats is affected by population state, invasion status, and host-tree conditions. Implications to management efforts intended to minimize MPB impacts and spread will be discussed
Theme 4: Consequences of mountain pine beetle outbreak on forest ecosystem services and landscape resilience
by Lael Parrott
Abstract: Ensuring ecologically resilient future forests requires a management approach that maintains the ability of the landscape to provide a range of ecosystem services upon which human communities depend for their livelihoods and well-being. Research in Theme 4 of the TRIA Network has explored the ecological and social impacts and responses to mountain pine beetle (MPB) outbreaks. While management responses to mountain pine beetle (MPB) outbreaks have typically addressed impacts on timber supply, the potential landscape-scale impacts extend beyond this single ecosystem service. We describe the range of consequences that MPB can have on forest ecosystem services and discuss how management approaches might take these into consideration.
Managing Risk in Forest Management: Challenges and Policy Impediments
by Marty Luckert
Abstract: Though foresters in Canada have historically engaged in long-term planning, such practices have generally not been sophisticated in dealing with uncertainty. Changes in climate and other trends affecting the forest industry, and their potential importance to future forests and their management, suggest new approaches could be considered for dealing with arising uncertainty. But there are a number of forest policies that constrain forest planning and management responses. Though such policies have historically been designed to enhance sustainability, they could actually stand in the way of such objectives in the context of current changes. Potential changes to these policies could improve our ability to alter forest planning and management practices to adapt to climate change.
Genomics and its applications to support forest sustainability
by Janice Cooke
Abstract: The first genomic resources for forest trees were developed a little more than 20 years ago. Today, genomic resources have been generated for many of western Canada’s economically and ecologically important forest tree species. These resources are being used by a number of research groups to investigate a wide array of questions related to forest resiliency and the sustainability of our forest resources. Importantly, with the maturation of genomics as a science and decreasing costs of using genomic resources, it is becoming increasingly feasible to develop practical genomic tools and applications that can be used to address key issues that impact forest sustainability. A number of examples will be presented from different research groups that illustrate recent application of genomics to pest risk assessment, tree improvement, traceability of genetic stock, diagnostics for insects and diseases, and reclamation. Emerging areas where genomic technologies could be applied to address forest sustainability will also be discussed.
Emerging forest insect threats in Canada: looking beyond mountain pine beetles to what might come next
by Allan Carroll for Jordan Burke
Abstract: While the threat of mountain pine beetle migration still stands, there are emerging threats from insect pests that are expanding into territory perilously close to the borders of the eastern provinces, as well as those expanding their range and impact in the west. Some of these insects potentially pose a bigger threat to the forest industry than MPB, and we must apply the lessons learned from the MPB situation in BC and Alberta. The most important factor if mitigation efforts are to succeed is early detection and rapid response. This is a difficult thing to accomplish, as often damage to trees might be conspicuous in the first and second year of attack. That means that predictions, based on models and field experiments, are critical to the effort, allowing practitioners to have some idea of where to look. Here, I will present information on insects we consider to be of concern, and some strategies learned from MPB that might aid in efforts to control them.
How healthy are Alberta’s forest landscapes?
by David Andison
Abstract: Threats to forests and landscapes come in many different forms. The most obvious are disturbances such as fires, floods and even MPB that have relatively sudden impacts that tend to demand most of our attention. But over the longer term, Alberta’s forested landscapes are slowly changing. Taken as a package, the various forms of human activity are decreasing diversity at both the landscape and stand scales, increasing risk to natural disturbance, and reducing, or even eliminating entire habitat types. Although slow and not particularly dramatic, most of Alberta’s forests are well into unfamiliar territory. The real danger is that because change is slow, we tend to not consider it a real threat that requires our immediate attention. The challenge is that by the time it becomes a more noticeable problem - or, more likely when it negatively impacts one or more of our goods and services - the time for effective mitigation may be past. I will use some meta-analyses from our new LandWeb model to demonstrate both actual and potential dangers.