Forest Investment Account (FIA) - Forest Science Program
FIA Project M075006

    Alternate Harvesting Policies on Area Harvested and the Area of Mature and Old Forest in the Nadina Landscape
Project lead: Steventon, Doug
Author: Steventon, J. Douglas
Imprint: Smithers, BC : Bulkley Valley Research Centre, 2007
Subject: Forest Investment Account (FIA), Dendroctonus Ponderosae, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
As harvest rates are dramatically increased in response to the Mountain Pine Beetle (MPB) (Dendroctonus ponderosae) epidemic, how to conduct harvesting in a way that best respects stewardship goals is a key question. Bunnell et al. (2004) provide a useful review of mostly stand-level approaches, but do not address the landscape scale in depth. Eng (2004) reviewed both stand-scale and landscape-scale stewardship principles, but did not conduct any assessment of feasibility. Our project proposes to build on those reviews, 'testing' some of the management principles on a real landscape through simulation modelling. The spatial patterning of salvage harvesting has been identified as a high priority topic in the Ministry of Forests and Range MPB research strategy ( There are many specific management questions. Given accelerated harvest rates, MPB-caused mortality and the existing management legacy, are there management strategies that better achieve stewardship goals? Does it likely make substantive difference how we pattern harvesting through time and space? How critical is it to effectively target the beetle kill? Do strategies such as seral-stage objectives by Landscape Unit, reserves and corridors still have application? How does potential climate change affect the outcome? These landscape-scale questions can only be explored rapidly enough for decision making through simulation modelling that applies theory and field research already available, explicitly recognizing the substantive uncertainties. The opportunities for designing longer-term adaptive management experiments can also be explored through modelling prior to making substantial investments. This project builds incrementally on work already underway . Ongoing field research is examining the responses of some key species (marten (Martes americana), flying squirrel (Glaucomys sabrinus), northern goshawk (Accipiter gentilis), lynx (Lynx canadensis) , hare (Lepus americanus)) to different harvest patterns. Modelling work associated with these projects has focused on creating habitat suitability models that account for the spatial distribution of habitats. Simulations of beetle-disturbance and timber harvesting have been developed in order to evaluate the future implications of the beetle outbreak and related management. We now feel the models have matured enough that with additional funding we can work with managers interactively to examine management inferences of particular importance to them. Additional funding will allow us to expand the number of MPB management scenarios, pursue questions about climate change interaction with MPB management strategies, and provide extension of the results to resource managers by working with them interactively. The management criteria we currently sumulate are harvest rate by Timber Supply Area (TSA); the distribution of harvest blocks (clumped vs. dispersed); assuming high priority for harvesting lodgepole pine. Additional criteria requested to-date in discussion with managers include Landscape Unit seral stage guidelines from the Land and Resource Management Plans (LRMPs), spatially fixed and/or 'floating' old-growth management areas and connectivity corridors, partial cutting, and varying priority of harvesting pine. Managers are interested in examining the relative benefits of such strategies, compared to, or in conjunction with, coarse-filter strategies that emulate natural disturbance (such as promoted under the Forest and Range Practices Act). An additional key question is how might landscape-scale MPB strategies interact with climate change scenarios for the region (Woods et al. 2005). Stewardship implications of these potential future landscapes are then assessed through a series of assessment models to examine impacts on species of varying life history attributes. Some Background Why do we need a spatially explicit modelling approach? Patterns created through forest harvesting are difficult and costly to change once established (Wallin et al. 1994), and thus need to be considered as early in stewardship planning as possible. Interactions among management strategies, natural disturbance, and the biophysical characteristics of large complex landscapes can only be explored using a spatially and temporally explicit approach (e.g., Fall et al. 2004; Armstrong 2005). This project examines the range of disturbance patterns that may be created in the context of dealing with MPB and evaluates selected ecological consequences. Historic timber harvesting, the biogeography of the landscape, the MPB epidemic, and perhaps climate change, are creating constraints on the landscape that affect the possible landscape patterns that can emerge. The conditions under which harvest pattern is important to stewardship objectives (beyond simple harvest rate which largely determines landscape composition) remain under debate. More data are needed from varying real-life landscape contexts (Boutin and Hebert 2002; D’Eon 2002). There is no debate about the importance of habitat variety and amount (composition). The importance of landscape pattern (as distinct from composition), however, has been debated for some time in landscape ecology circles, but not often rigorously tested at large spatial scales (Harrison and Bruna 1999; D’Eon 2002; McGarigal and Cushman 2002). There has been a recent swing of opinion (although far from a consensus) towards the view of pattern being of minor importance except when habitat abundance is very low (see reviews by Boutin and Hebert 2002; D’Eon 2002; Fahrig 2002). We feel this conclusion may be premature. The evidence against pattern being important is mostly based on empirical studies of the abundance of smaller vertebrates (especially song birds, e.g., Schmiegelow and Mönkkönen (2002)), and on dispersal processes affecting simulated metapopulation dynamics (e.g., Fahrig 2002). These are perhaps not the limiting processes compared to edge effects or habitat dilution (patch density) effects (Harrison and Bruna 1999; Daust et al. 2003). While most vertebrate species likely disperse adequately through fragmented landscapes (D’Eon 2002), pattern may affect access to sufficient resources on a daily or seasonal basis. Species body sizes and spatial requirements may have evolved to be consistent with the structural attributes of landscapes (Holling 1992; Schmidt and Jensen 2003). This effect is expected to be strongest for territorial species that must integrate sufficient suitable habitat within a limited size area, and/or species that are strong habitat specialists (With and Crist 1995; Andren et al. 1997). We are examining the implications of both this 'habitat dilution' effect and the potential for dispersal effects.
Contact: Steventon, Doug, (250) 847-6393,


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Updated August 16, 2010 

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