The Integration of Climate Change and the Development of Adaptive Capacity into the Determination of Allowable Cuts in Quebec Forests

Context

Climate change transforms forest ecosystems by altering their productivity, composition and structure. These changes are now taken into account in the management of forest resources, and doing so is a legal requirement under Quebec’s Sustainable Forest Development Act. It is becoming essential to apprehend the risks associated with climate change and to understand how the forest management strategies applied today could influence the forest of tomorrow.

In Quebec, the main mission of the Chief Forester is to determine allowable cuts. To do this, changes in the forest over a 150-year period are modelled using assumptions based on stable environmental conditions derived from historical data. Currently, in the determination of allowable cuts, the risks to the forest mosaic associated with climate change are not taken into account due to a lack of knowledge and of a methodology compatible with the calculation of allowable cuts.

Objective(s)

To undertake the process of integrating climate change adaptation measures into the process of determining allowable cuts
To develop an approach that will allow better decision-making with regard to the sustainability of forest resources and the choice of the most appropriate forest management strategies in the face of the apprehended risks
To meet the requirements of the Sustainable Forest Development Act and guide today’s strategic choices to ensure the permanence of the forest and a resilient forest industry under future conditions

Methodology

Development of regional modelling integrating the effects of climate change
Modelling of the effect of forest management and natural disturbances
Development and testing of adaptation methods and communication of results to support decision-making

The work undertaken in this project is not intended to replace the calculation of allowable cuts. Rather, it is a complementary process that is independently assessed and aimed at informing decision-makers about the risks associated with different climate scenarios.

Results

For the Saguenay–Lac-Saint-Jean region, given the assumptions of the model, the results suggest that the forest of tomorrow will be different from that of today. Shorter fire cycles are to be expected and could result in a significant loss of productive forest area. Although some gains in the growth of softwood and hardwood species are expected, these will not compensate for the effect of fires on long-term forest resources; hence the need to develop effective adaptation methods.

Figure 1. Probabilities of fire initiation in the landscape.

In light of the results presented, it is reasonable to believe that the structure as well as the dynamics of the forest will alter due to climate change, and adaptations in forestry practices will be required. For example, enriching the forest composition with deciduous trees would reduce the flammability of the forest, but would have the consequence of inverting the softwood and hardwood proportions of the forest. This would require significant adaptation by the forest industry, which would no longer have access to its usual supply. In addition, land-based forest firefighting and large-scale recovery of burned wood rely on maintaining constant access to the forest by means of a sufficiently well-developed road network. However, this is not desirable with respect to the protection of the woodland caribou habitat.

In such a context, maintaining the current management strategy in the face of climate change risks producing forest conditions that are unacceptable in terms of the sustainability of the forest resource. Although the results of certain adaptation methods, such as the intensification of forest management and enrichment with deciduous trees, demonstrate that it is possible to mitigate the impacts of climate change, actions must be taken today to ensure that the forest of the future lives up to the public’s expectations. We must therefore collaboratively define a vision for the forest of tomorrow and promptly act accordingly.

Figure 2. Average values of merchantable volume modifiers (weighted by area) over the 150 years of simulation of the status quo scenario under (a) RCP 4.5 and (b) RCP 8.5 for the volume of softwood (in green) and hardwood (in orange). The dotted line is the value of the modifier (equal to 1) under the assumption of a historical climate.

At the same time, it will be necessary to deepen knowledge of the impacts of climate change and integrate it into modelling in order to obtain a clearer picture of the future. The role that assisted migration can play in adaptation will need to be explored and tested in the field. The effects of existing and innovative silvicultural treatments under climate change will also need to be assessed. The deciduous forest, with its own dynamics and silvicultural management, will have to be integrated into the process. The effect of the spatial context on the initiation and spread of fires should be better understood and integrated into the modelling. The uncertainty associated with the stochasticity of natural and anthropogenic disturbances and the effect of having multiple decision-makers must also be integrated into the decision-making process.
Lastly, the results underline the importance of maintaining efforts to mitigate greenhouse gas emissions, as the simulations under the RCP 8.5 scenario predict a situation that is difficult to maintain for the forest and all the ecosystem services that it provides, including carbon storage. Indeed, significant losses of productive forest area, as suggested by the results, would lead to reduced storage capacity.

Benefits for adaptation

The approach developed provides decision-makers with a decision-making aid process that summarizes the results of the model.

The Chief Forester recommends the pooling of research and development efforts among the various stakeholders and researchers, both within the Ministère des Forêts, de la Faune et des Parcs and externally, to find innovative solutions to adapt the forest, the forest environment and forestry practices to climate change.

This pooling could save time when implementing new strategies, and could also save money if research efforts are well coordinated. The Chief Forester will continue to apply this new knowledge.