Bark type reflects growth potential of yellow birch and sugar maple at the northern limit of their range

We carried out a study to determine if bark type could reflect the growth potential of yellow birch (Betula alleghaniensis Britt.) and sugar maple (Acer saccharum Marsh.) at the northern limit of their range in Québec, Canada (47°N, 75°W). We measured a large sample of 266 trees that ranged in size from 95 to 712 mm in diameter at breast height, on two independent study sites. Our results suggest that trees with smooth bark type had mean 5-year diameter increment 8 and 11 mm higher than trees with rough bark type, depending upon the study site. Differences in growth of 8 and 11 mm represented 85% of the overall rough bark type increment in the first site and 78% of the overall rough bark type increment in the second site. The rapid identification of a tree’s growth potential using bark type could be of great use to practitioners because it avoids the need to bore trees to collect increment cores, which injures trees and may serve as an entry point for disease. Moreover, the proposed method helps protect or release the smallest trees with high growth potential and remove trees with low growth potential. While the proposed method is valuable to practitioners operating in uneven-aged forests, its applicability still needs to be tested in evenaged forests.