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| Trees engulfed by competitor plants may grow slowly or even die, hindering the renewal of our forests. Vegetation management helps free valued trees from the competition. |
Over the past few years, OFRI researcher Wayne Bell, Lakehead University’s Nancy Luckai, and the Canadian Ecology Centre-Forestry Research Partnership’s Al Stinson and Sue Pickering have co-led a project with partners from British Columbia, Ontario, Quebec, and New Brunswick to summarize what is known about methods to control vegetation that competes with conifers.
These researchers have been looking at not just the environmental consequences of using various vegetation management treatments but also the social and economic implications of conifer release at the stand and landscape levels. They have focused primarily on results of studies in Ontario’s managed forests begun during the early 1990s under MNR’s Vegetation Management Alternatives Program but have also reviewed results from other studies across Canada.
“We wanted to pull together all the work that has been done over the past two decades,” Bell explains. “Individual projects have been reported on in various places, but the information was scattered and needed to be summarized and made accessible to practitioners. The goal is to help forest managers choose the most effective treatment for their sites and circumstances.”
He points out that vegetation management helps direct light, water, and nutrients towards crop trees to improve their survival and growth. ”Forest managers choose treatments based on a combination of the autecology of the site’s competitor species, management objectives, and other values, as well as environmental and socioeconomic considerations.”
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| During a field tour, OFRI research scientist Wayne Bell (far right) reveals new insights into managing vegetation that competes with crop trees. |
Al Wiensczyk and Kathie Swift, of FORREX (Forum for Research and Extension in Natural Resources), a not-for-profit organization in British Columbia, have been key players in summarizing the literature to determine what’s known about the silvicultural effectiveness and ecological effects of various treatments. Wiensczyk explains that treatment options can be categorized into:
- Harvest systems and physical: site preparation, brushing, girdling, mulching
- Thermal: fire, steam
- Cultural: seedling culture, cover crops, grazing
- Chemical and biological spray treatments
“These reviews have been based partly on information from the Canadian Forest Management Database set up and maintained by Dean Thompson, Natural Resources Canada, and co-sponsored by the Canadian Ecology Centre-Forestry Research Partnership,” Wiensczyk says. “This database contains about 14,500 citations relevant to forest management in Canada, particularly controlling competing vegetation, insects, and diseases.”
When asked to share some of the findings to date, Lakehead University graduate student and former OFRI intern Krishna Homagain reports: “Herbicides are still the most cost-effective alternative we have. For example, tenth-year results from one of our biggest studies, the Fallingsnow Ecosystem Project, show that brushsaw and mechanical brush cutter treatments cost three times as much as herbicide per cubic metre of wood volume.”
Researchers Stephen Wyatt, Université de Moncton, and Marie-Hélène Rousseau, Université Laval, are summarizing the social issues related to vegetation management alternatives. They have proposed a framework within which to evaluate public concerns and stress that people view and accept vegetation management alternatives based on context, risk, aesthetics, trust, and knowledge. They caution that people’s acceptance of alternatives can change over time and among situations and they perceive risk based not just on science but also values, concerns, and trust in decisionmakers and resource managers.
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| Brush saws are one option for controlling the growth of plants that compete with high value trees such as jack pine and black spruce. |
“Regardless of method, early release treatments generally result in more conifer fibre in the long term,” Bell says. “The trick is getting a combination of treatments that ensures we achieve the long-term objectives for a given site.”
According to Eacom Timber Inc. (formerly Domtar) biologist and research team member Kandyd Szuba, based in Espanola, ON, the landscape-level case study analysis focused on the longer-term consequences of various release alternatives within the framework of forest management plans (FMPs). The wood supply models used for this analysis represented two MNR-approved FMPs (including all objectives and ecological constraints): for the Spanish Forest (non-spatial SFMM analysis) and for the Romeo Malette Forest (spatial Patchworks model).
Working with Szuba is OFRI forest research ecologist Jennifer Dacosta, who reports: “In our case studies, reducing herbicide use resulted in less area harvested, less spruce-pine-fir wood volume harvested, lower net revenue to the Crown, a larger network of active roads, and higher cost to maintain roads and haul wood. But it produced more old growth forest – more than needed to meet ecological targets; more habitat for wildlife preferring mature and old forest, such as black-backed woodpecker; and less habitat for wildlife species preferring young or recently disturbed forest, such as kestrel, moose, and white-throated sparrow.”
So how are the researchers sharing their findings? Project partner John Pineau of the Canadian Institute of Forestry (CIF) says, “We are now transferring the results via regional workshops, presentations, the CIF lecture series, and articles in a special issue of The Forestry Chronicle in March/April 2011 to get this information out to as many resource managers as possible.”
Partners in the synthesis project are Lakehead University, the Canadian Ecology Centre-Forestry Research Partnership, Canadian Institute of Forestry, FORREX, Eacom Timber Inc., Tembec Enterprises Inc.-Forest Resource Management Group, Spatial Planning Systems, Université de Moncton, Université Laval, Canadian Forest Service, Québec Ministère des Ressources naturelles et de la Faune, University of Guelph, and the National Council for Air and Stream Improvement-Canadian Operations.
Want to read more about vegetation management?
- The March/April 2011 issue of The Forestry Chronicle focuses entirely on vegetation management
- Also see Insights (Vol. 8, No. 1, Page 14) | Insights (Vol. 5, No. 2, Page 1)
- Also available: Vegetation Management Alternatives - A Guide to Opportunities (for a paper copy, e-mail OFRI)
- Or listen to a WebEx recording of the 2010 presentation Vegetation Management Alternatives in Boreal and Temperate Forests: What Do We Know About Releasing Conifers?
