Theme 6 | Implementation of Alternative Silvicultural Treatments and Multi-Species Plantations

There’s almost always something new to learn about forests; about how they grow, and how they evolve through time in their own peculiar way. That’s why, although we now have powerful computer models to try and predict how they change through time (see theme 4), there’s always a need for more data coming from observation.

Such data is crucial for the DIVERSE project, as we’ll recommend the implementation of new forest management strategies and practices. We need to have as much precise data as possible as to the effect of these strategies and practices. How will new tree species recommended in theme 2 to be planted grow in the different provinces of Canada ? Would plantations work better as multi-species plantations ? How do different types of forest cuts affect the natural regeneration of the species we want to keep in a given forest stand ?

Theme 6 aims to design and field test the most promising silvicultural approaches that will be needed to implement the CSF (Climate Smart Forestry) and FCN (Functional Complex Network) strategies studied in theme 1-5. The selected sites will become both a testing ground for these approaches, but also demonstration sites to showcase various silvicultural approaches aimed at adapting forest to climate change and increasing their resilience.

In particular, we will focus on three types of treatments : First is the manipulation of the soils and the composition of tree species of forest stands. The goal of such treatments will be to favor the natural regeneration of the tree species with key functional traits whose abundance in the stand we want to increase. These treatments will create canopy openings of different size and intensity to allow more or less light to reach the ground, but they will also act on the soil of the forest to favor some species among others. Second is what we call enrichment planting, which aims to increase the functional diversity and resilience of the forests treated by planting species with key functional traits. We will test the planting of species from more southern provenances, but also of species not present in the research site. Thirdly is the test of mono and pluri-specific plantations, to see if the juxtaposition of fast-growing and slow-growing trees in plantations might perform better than the use of only one species while planting.

The first step will be to identify suitable locations for these field tests across our research sites, as well as the treatments that will be tested there. We will do that by 1) identifying the tree species and mixtures that have performed well in the past while suffering from several stressors (theme 1), 2) review the literature to inventory existing field trials and plantations in Canada, 3) determine which tree species should be planted and where in Canada (from theme 1-3), and 4) evaluate the social acceptability of the different practices we select (theme 5). We will also identify older experimental treatments and forests that might provide important data and insights for the goal of DIVERSE with a careful re-examination.

We will then establish demonstration silvicultural sites across Canada based on the sites and treatment we have identified. We will do this around year 2 and 3 of the DIVERSE project, around 2026-2027. We will then carefully monitor the aboveground and belowground of the naturally regenerated and planted tree species in the field sites, while taking into account the presence of browsing by different animals which might influence their growth.