A reexamination of moose damage to balsam fir–white birch forests in central Newfoundland: 27 years later

Abstract

A 1960 study from central Newfoundland suggested that moose (Alcesalces L.) would: (i) reduce the commercial value of second-growth forests of central Newfoundland by excessive damage to balsam fir (Abiesbalsamea (L.) Mill.); (ii) eliminate white birch (Betulapapyrifera Marsh.) from the forest canopy; (iii) alter conifer species composition; and (iv) reduce the carrying capacity of the area for moose. We resurveyed the original study areas in 1987. Our data suggest that moose have altered species composition in favour of white spruce (Piceaglauca (Moench) Voss) and black spruce (Piceamariana (Mill.) B.S.P.) on some sites and have reduced the mean height of balsam fir trees. White birch was generally absent from the canopy. However, contrary to the 1960 prediction, moose appear to have had a positive influence on forest growth by thinning most areas to stem densities comparable with those of precommercially thinned stands. Data from this study were compared with a general model of the influence of moose on balsam fir forests developed for Isle Royale, Michigan. Our data supported two predictions from Isle Royale: moose damage was highest at low balsam fir densities and at highest moose densities. Our results contradicted a third prediction, that height growth was greater in high density stands of saplings. Also, unlike at Isle Royale, despite heavy browsing pressure for extended periods, balsam fir will continue to dominate central Newfoundland forests.