Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Abstract

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples of Calluna in western Europe, Kalmia in Newfoundland, and Gaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth of Calluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controlling Kalmia and Gaultheria, however, have yet to be developed. While the Kalmia- and Gaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range of Calluna heathlands of western Europe are being conserved as natural and seminatural vegetation. © 1995 Springer-Verlag New York Inc.