Forest Investment Account (FIA) - Forest Science Program
FIA Project Y081160

    The application and evaluation of an ecosystem model to project the recovery of old-growth attributes in second-growth stands
Project lead: Seely, Brad (University of British Columbia)
Contributing Authors: Seely, Brad A.; Gerzon, Michael
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
One of the key issues facing forest resource planners throughout BC is the conservation and promotion of old-growth characteristics in managed forest landscapes. The economic viability of the relatively young forest products industry in British Columbia is dependent on the continued harvesting of old-growth or previously unharvested forest (Beese et al. 2003). Yet, consumers, environmental organizations, and BC residents alike have made it abundantly clear that the preservation of old-growth forests is essential for the industry to maintain its social license to harvest on public lands. These issues continue to be debated with the ongoing development of the North Coast and Central Coast Land and Resource Management Plans (LRMPs) ( While stakeholders in the LRMPs generally agree on this goal in principle, there is still much uncertainty with respect to the development of specific management practices, criteria, and indicators to be employed towards this end.
One approach to dealing with this dilemma has been the development and application of new silviculture systems such as variable retention harvesting designed to maintain within-block, large live trees with the objective of mitigating the prolonged loss of old-forest structure associated with clearcut harvesting. While these systems have showed some promise in addressing this issue in the short-term (e.g. Beese et al. 2003), we lack the long-term field experience with such systems required to effectively project their long-term impacts on the growth and development of forest resources and associated values. In the meantime there are significant areas of previously harvested or otherwise disturbed ‘second-growth’ stands distributed throughout the Central and North Coast forest regions. As these forests continue to develop and mature they too will develop or have already begun to develop old growth attributes and thus should be accounted for, to an appropriate degree, within existing forest resources inventories. Despite the fact that "old" forests are widely recognized as reservoirs of biodiversity containing a wide range of unique habitat structures, the definition and quantification of these and other attributes that qualify a forest as "old-growth" have been notoriously difficult to define and quantify in the context of forest resource planning (Kimmins 2003). Presently, the lack of viable alternatives has forced managers to rely upon estimated stand age as the principal determinant of "old growth" with somewhat arbitrary thresholds based on expert opinion. This is further problematic as habitat relationships of old-growth-associated species are typically understood in terms of structural characteristics as opposed to age itself (e.g. Wells 1996; Mosseler et al. 2003).
The use of normalized old-growth indices (OGIs) has been suggested by several authors as a good alternative for quantifying the old-growth characteristics in managed landscapes. However, these have been shown to be ecosystem specific and are only effective if supported by extensive regional field data (Mosseler et al. 2003). The Ecosystem Recovery Project, established by the BC Ministry of Forests in 2003, was developed to assess how quickly specific old-growth characteristics can develop in second-growth stands resulting from both harvesting and natural disturbance agents by sampling a wide variety of stands of many ages, site qualities, and species combinations. Measurements have included overstory and understory vegetation species and cover, CWD surveys, timber cruise plots for volume, stems per ha by diameter class and species, etc., seedling surveys, epiphyte surveys on sample trees, soil descriptions and soil faunal sampling. Efforts to date have been focused in the coastal western hemlock (CWH) zone of north/central BC but funding has been recently increased to expand the project into several other zones including the ICH and SBS in the northern interior in 2007.
To effectively harness the knowledge derived from this extensive database and extend it to landscape planning operations, it is necessary to go beyond summarizing the data and basic statistical analysis. The effective extrapolation and extension of this information to support sustainable forest planning requires the development and use of scientifically credible decision-support tools. Such tools should allow for the representation of ecosystem development following various management activities and should be able to project trends with respect to the development of old-growth stand characteristics as defined by an appropriate suite of indicators and/or old-growth indices. The FORECAST (Kimmins et al. 1999) model and its spatially explicit, watershed-scale derivative LLEMS (Seely 2005) have been developed for such applications and have been used within the BC forest industry in developing SFM plans (e.g. Seely et al. 2004, Welhem et al. 2004). However, to gain confidence in model projections it is necessary to validate or evaluate output against field observations. The Ecosystem Recovery Project provides this opportunity.
Literature Cited (all sections) Blanco et al. (In Review). Testing the performance of FORECAST, a forest ecosystem model, against 29 years of field data in a Pseudotsuga menziesii plantation at Shawnigan Lake. Can. J. For. Res; Beese et al. 2003. For. Chron. 79(3):570-578; Kimmins et al. 1999. Ecol. Mod. 122:195-224; Kimmins 2003. For. Chron. 79(3):429-440; Kneeshaw et al., 2000. For. Chron. 76: 481-493. Kremsater 2003; For. Chron. 79(3) 429-440; Mosseler et al. 2003. Environ. Rev. 11: S1–S7; Seely et al. 2004. For. Ecol. Manage. 199:283-305; Seely 2005. South Coast LLEMS Project Phase 3: Application and Evaluation. Report prepared for International Forest Products.; Seely et al. (In Review). Evaluation of an ecosystem-based approach to mixedwood modelling. For. Chron.; Welhem et al. 2004. Establishing targets and trajectories for selected ecological indicators of SFM on TFL 57. Report prepared for Iisaak Forest Resources Ltd.; Wells 1996. Developmental trends of stand structure in CWH forests. Masters Thesis. SFU.; Yamasaki et al. 2002. For. Chron. 78:487-491.
Related projects:  FSP_Y092160
Contact: Seely, Brad, (604) 822-8958, brad.seely@ubcca


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Updated August 16, 2010 

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