By Megan de Graaf, Forest Ecologist, Posted on May 3, 2019
Climate Change in the Acadian Forest
Here in New Brunswick, we live amid a unique forest type known as the Acadian Forest. This forest type covers all of the Maritime provinces and northeastern US, and is a mix of cold-loving (boreal) species like spruces, poplar, grey and white birch, and balsam fir, and more southerly species like oak, hemlock, maples, and ash. Climate change, along with a number of other human-based activities, threaten this unique mix of species and habitats, which is why it was listed in 2005 as an endangered forest type by the World Wildlife Fund. Climate change is modifying the growing conditions of the region, in very broad terms, this region is becoming warmer and wetter. That means that the species of trees growing here must either adapt to the changes, or lose the fight.
For trees, which grow slowly and therefore can adapt only slowly, these changes are likely to disadvantage those cold-loving boreal species and provide more encouraging growing conditions for the southern-affiliated ones. Species like the spruces and fir have growing ranges that will shift northward as the climate here warms. Southern-affiliated species like oaks and ash will find their growing ranges expanding and also moving northward as the climate warms. When adding into this the uncertainties and influences of incoming forest diseases and pests, many of which may have widespread effects on our forest, this means that in the next 100 years, our forest composition is likely to change dramatically.
There has been quite a lot of research done in the last several years in the region on modeling what this future forest will look like, and in calculating the changes in growing ranges for individual species. Our friends at The Fundy Biosphere Reserve have done quite a lot of modeling on which native species will decline, persevere, and prosper over the next 100 years, and have come up with a list of eight winners under the changing climate.
These eight species are those native to New Brunswick that are most likely to prosper as the climate changes: black cherry, eastern hemlock, red maple, white pine, ironwood, American beech, red oak, and sugar maple. They cover a range of growing conditions (i.e. moisture and light tolerances), and since they already grow in the province, they can be safely planted throughout the province. In fact, we should all be making a concerted effort to plant these species throughout the province, to get a jump on filling in the gaps in our forest that may arise as those other boreal species decline.
Non-Native Species and “Assisted Migration”
A number of species that are currently not native to eastern Canada are likely to migrate into this region over the next 100 years, as conditions here favour those southerly species. There is a lot of debate swirling about assisted migration: proactively planting those non-native species to keep our forested landscape forested as other species dwindle. But assisted migration comes with a whole host of unknowns: what will they do to wildlife habitat in the region, how potential pests and diseases of those species will interact with native species, the possibility of a non-native species becoming invasive and crowding out native species, just to name a few. For now, the safest place for non-native species to be planted and monitored is in urban parks and botanical gardens, and not out in woodlots. For the vast Acadian forest of this region, the best trees to plant are those that are native and projected to survive the changes ahead.
For more detailed information on what the Acadian forest will look like over the coming years, including maps and a planting guide visit The Fundy Biosphere Reserve’s website.