“Forestry is not rocket science…it is much more complicated than that”. 1
Managing for biodiversity in harvested forests is no easy task. Managers have few ecologically-based rules that can be used to guide practices and for those that do exist, there is often much uncertainty in their use. For example, if ‘large cutblocks’ are generally avoided, subsequent use of smaller cutblocks across landscapes eventually results in more ‘edge habitat’ in the short-term, and less large tracts of old growth forest in the long term. This cutblock pattern will benefit some species, but will also negatively affect others, like those that reproduce less or die at forest edges (eg. some lichens and bryophytes) and those requiring large tracts of old growth forest (eg. marten martes americana). In the absence of specific rules and with limited knowledge of the impact of management actions on forest biodiversity, various approaches or steps have been recommended to help with management decisions. Among others, McComb (1999) recommended 10 steps (see textbox below).
This website describes a four-steps approach, using a Criteria and Indicator framework, for assessing and monitoring the effects of forest practices on biodiversity. It also summarizes six approaches to biodiversity management mostly used: management by objectives (Criteria and Indicator), management by species, management by a natural range of variability approach, adaptive management, ecosystem management, and a minimal ‘default’ approach outlined by laws and policies in British Columbia.
Three more broad topics are discussed in this section of the website:
Why manage for biodiversity? This page briefly summarizes the social and economic pressures under which managers operate and the importance of sustainable biodiversity.
Management issues This page describes scale of management and planning, location/geography, knowledge limitations, natural disturbance, and fragmentation and connectivity.
10 steps to forest management for biodiversity (adapted from McComb 1999)2:1. Relax, your job is not only way more difficult than you think, but way more difficult than you can think. [“Ecosystems are not only more complex than we think they are, they are more complex than we can think they are.” Frank Egler, 1977].
2. Ensure that there is enough habitat first, then worry about how that habitat is distributed across the landscape.
3. Before you harvest, first figure out how harvesting will change the landscape through time to avoid irreversible patterns in patch sizes and distribution.
4. While harvesting, retain habitat structures like snags, shrubs, decaying wood, and large live trees.
5. Use modeling and other tools to predict the consequences of various management options on species, especially those negatively impacted by forest harvesting.
6. Think: landscape scale. Work with managers and owners of adjacent landscapes.
7. Think: natural disturbances.
8. Monitor. Evaluate. Adapt.
9. Don’t do the same thing everywhere all the time.
10.Remember Step 1 while figuring out what to do for Step 11.
1Bunnell, F.L. 1999. Forestry isn’t rocket science – it’s much more complex. Forum. Publication of the Association of British Columbia Professional Foresters 6:7.
2McComb, W.C. 1999. Forest fragmentation: wildlife and management implications synthesis of the conference. In J.A. Rochelle, L.A. Lehmann and J. Wisniewski (eds.), Forest Fragmentation: Wildlife and Management Implications (pp. 295-301). Brill, Leiden, Netherlands.