NEW RESEARCH GUIDES ECOSYSTEM MANAGEMENT
by Sylvie Gauthier, Marie-Andrée Vaillancourt, and Yves Bergeron

Ecosystem management is a concept that emerged in western North America in the 1990s as the extent of logging activities and concomitant threats to species encouraged the adoption of ecologically sensitive forestry practices. This shift has been observed in several Canadian provinces with various initiatives such as the ecosystem-based BC Forest Practice Code and Ontario Ministry of Natural Resources’ Forest Management Guidelines. In Québec, the Coulombe Commission, an independent inquiry on forest management held in 2004, made the recommendation that an ecosystem-based forest management regime be implemented on public lands. As this recommendation created important expectations from the public, forest industries now need information on how ecosystem management (EM) frameworks must be designed and implemented throughout Québec’s forested land. The results from research projects conducted within the Sustainable Forest Management Network are providing important insights into the ways natural forest disturbances can develop ecological forestry. 

Numerous studies have been conducted, especially in the boreal zone, to promote the understanding of forest dynamics and functioning, and how forest harvesting practices can more accurately maintain or create conditions similar to those induced by natural disturbances on the landscape. One of the fundamental findings of this work is that the boreal forest is a system that is more complex than originally thought. In fact, complex fire patterns, insect infestations, and windthrow create considerable diversity in forest conditions. This leads to the following question: how can forest management deal with and maintain such complexity? This is exactly what EM is about.

What is ecosystem management?
Defining EM is not an easy task and agencies have their own definitions. However, there is consensus on the main goal and characteristics of EM. According to the Coulombe Commission, the main goal of EM is to maintain biodiversity and viability of all forest ecosystems while meeting socio-economic needs with respect to social values linked to the forest. Adopting EM in forest policies and practices implies a major change of perspective notably with regards to spatial and temporal scales. Since forest ecosystems have variable boundaries and change over time, forest management must integrate larger spatial and temporal scales. Furthermore, EM must be based on relevant, scientific knowledge about forest dynamics and natural disturbances while being flexible enough to integrate new findings and uncertainties. 
Knowledge of natural disturbance effects and variability should guide the development of management strategies that complement natural forest conditions. Integrating this knowledge does not mean that we can mimic nature. Instead, we can use our understanding of natural ecosystem functioning and disturbance dynamics and their effects on the forest mosaic to conceive management strategies and silvicultural methods that can reduce the negative impacts of forestry practices. Using natural disturbances as a template to develop an EM framework is probably the best way to maintain biodiversity in forest ecosystems while ensuring that forest productivity and associated economic activities are maintained over the long-run.

Implementing an EM framework can be accomplished in five steps:
1. Reconstitution of the natural disturbance regime and long-term evolution of forest stands following disturbance.
2. Comparative analysis of natural and managed landscapes and identification of the main differences.
3. Fixing management objectives and silvicultural actions to minimize differences between forest management and natural forest dynamics.
4. Implementation of silvicultural actions in the context of a forest working plan that takes into account social acceptability and economic feasibility. 
5. Monitoring interventions to evaluate management objectives and modify silvicultural actions if needed.

Is even-aged management ecosystemic?
The assumption that the boreal forest was characterized by the occurrence of large and severe fires occurring approximately every 100 years has justified the use of clearcutting. However, recent results have shown that in many boreal regions fire intervals exceed 100 years, leading to large areas of old-growth forest cover. The proportion of old-growth forest cover has decreased due to current even-aged forest management practices, which risk the biodiversity and viability of these ecosystems. To reduce this risk, alternative forest practices recreating old-growth conditions must be developed and deployed on the land base.

Knowledge of historical fire intervals can help determine even-aged management targets within a global EM strategy. In many parts of the boreal forest, fire occurs less frequently than it used to. Thus, even-aged management systems could be used to replace the proportion of territory that would have burned under past fire regimes. (However, in a large proportion of the forest management units, this even-aged management has to be complemented with other silvicultural treatments aimed at maintaining old-growth characteristics.) Fire size and configuration must also be considered when planning harvest block dispersion in even-aged systems. Fires can range in size from small fires covering less than a hectare, to large fires covering thousands of square kilometers. Like fire, forest management tends to create large regenerating areas. However, large fires don’t occur that frequently. To recreate patterns of fires, harvesting should be variable in size and large regeneration areas could still be created. However, they should be distributed within a management unit in order to keep large tracts of both mature and old-growth forest in which alternative practices could be used to compensate for the reductions of even-aged management areas.

Alternative management practices
Silvicultural practices aimed at maintaining structural and compositional characteristics of overmature stands within treated stands could, in the boreal forest, guarantee maintenance of habitat diversity while slightly affecting allowable cut. Forest stands that have not been affected by fire for a long period of time are more susceptible to be affected by other disturbances such as insect outbreaks and windthrow which, like fire, have variable effects on forest stands with respect to size, frequency, and severity of disturbance events.

Thus, it is possible to treat some stands by partial and select cuts in order to reflect the dynamics of old-growth stands. Several uneven-aged practices exist in silviculture, but for economic and productivity reasons, these techniques have not been widely used in boreal forests to date. However, with EM management, managers can utilize a wider variety of silvicultural treatments which are closer to natural disturbances in relation to their impacts on the forest ecosystem. 
It is important to note that the choice of silvicultural techniques used to set up the uneven-aged management system will depend on management objectives determined from natural disturbance regimes. Therefore, there is no single recipe in the utilization of such a management system. The key to creating appropriate silvicultural systems will be the creativity of the foresters and not adherence to a predefined set of rigid rules.

Paludification
Paludification is the gradual conversion of a dry forest to a forested peatland through the accumulation of organic material. In the northern Clay Belt region (Québec and Ontario), forests are very susceptible to paludification because of the flat topography. Black spruce stands in heavily peated areas tend to become successively less productive because of the accumulation of organic matter. High severity fires can reverse the paludification process by consuming the organic layer while contributing to the recovery of stand productivity. On the other hand, low severity fires that do not consume the organic layer can contribute to the creation of unproductive forest stands with low tree density. Predominant harvesting practices (CPRS in Québec and CLAAG in Ontario) currently remove the tree layer while leaving the organic layer (forest floor) intact. Interestingly, although these practices were designed to increase yields and reduce regeneration costs by protecting advanced regeneration, their effect is similar to low-severity fires. Hence, these practices may be leading to increased paludification and significant losses in stand productivity. Alternative treatments that would reproduce the effect of fire on soil’s organic layer include soil scarification disturbance and prescribed burning.

Conclusion
Current forest management practices are eliminating old forest habitats at an alarming rate. One management option to avoid this outcome, with negligible impact on timber supply, is to rely more on uneven-aged silviculture. In some regions, to counteract paludification, the industry also needs to adopt silvicultural treatments that mimic natural disturbances such as fire to create a healthy, organic soil layer and productive stands.

Dr. Sylvie Gauthier is a research scientist at Natural Resource Canada - Canadian Forest Service working on the effects of fire on dynamics of boreal forests. She is the principal editor of an upcoming book on EM in boreal forests. She can be reached at sylvie.gauthier@cfl.forestry.ca. Marie-Andrée Vaillancourt is a biologist and co-edited the upcoming book with Dr. Gauthier. Dr. Yves Bergeron is professor at the Université du Québec in Montréal and the Université du Québec in Abitibi-Témiscamingue. He holds an industrial chair in sustainable forest management and a Canada research chair in ecology and forest management.