The history and tree stratum of an old-growth forest of Haut-Saint-Laurent region, Quebec

Abstract

An old-growth forest of presettlement origin was recently discovered at the northern limit of the Eastern Deciduous Forest (sensu Braun 1950) of North America, in an area that is extensively affected by logging, land clearing, and agriculture. In a study of the disturbance history, forest composition, and dynamics of this old-growth forest, we found that (1) the preservation of the forest can be attributed to the initial settler’s lack of interest in exploiting it and to a strong sense of conservation by his descendants; (2) an American elm-black ash (Ultnus americana L.-Fraxinus nigra Marsh.) community occupies more hydric sites(approximately 15% ofthe forest) and a sugar maple -American beech (Acer saccharum Marsh.-Ftzgws grandifolia Ehrh.) community occurs on mesic sites; (3) larger canopy trees range in age from 150 to 300 years; (4) despite the absence of any major perturbation in the mesic portion of the site, the composition is not in equilibrium and beech is apparently increasing in abundance over the presently dominating maple; (5) the average tree growth has been very slow compared to that of trees in adjacent disturbed forests. Ecological information obtained from old-growth forests can contribute to decision making in management of natural areas.