Vegetation management alternatives in young plantations: An integrated ecological approach

摘要

World-wide rise in demand for forest products particularly wood fiber and lumber has put increased pressure for producing more of these products from limited forested land base. Even in the optimistic scenario under the existing extensive forest management regime predicts wood supply shortage in Ontario in the very near future. The 'wood supply gap' has been identified as the most critical issue facing the forest industry in the northeast and northwest Ontario (OMNR 2004). In the boreal forests of Ontario interfering vegetation layer at the early stage of conifer regeneration has been a serious impediment of forest productivity. Competition control at this stage of secondary succession is often predicated to forest productivity. However, the commonly used competition control strategy by using herbicides has been faced with public criticisms (Wagner et al. 1998). Although forestry application of herbicide such as 'Vision' (Glyphosate) and 'Release' (Trichlopyre) can successfully control certain competing vegetation and thereby improve crop tree growth their adverse effects on non-target plants such as blueberry (Vaccinium angustifolium and V. myrteloides) an important food source for human as well as wildlife such as black bare (Ursus americanus) raised serious concerns (Rogers 1976, 1987). Manual and motor-manual brush cutting have been suggested as alternative to chemical control of competing plants (Wagner et al. 1998). In order to compare the efficacy of different vegetation control techniquesin young plantations the Ontario Ministry of Natural Resources (OMNR) established several experimental trials under a provincial Vegetation Management Alternative Program (VMAP) in the early 1990s (Wagner et al. 1994). Canadian Forestry Service also established similar experimental trials to determine crop tree response to vegetation management (Sutton 1994). Results of these studies have been published in several peer-reviewed journals and internal reports focusing on response of competing plants andcrop trees (Mallik et al. 1997a,b, 2002; Bell et al. 2000; Pitt and Bell 2005; Greifenhangen et al. 2005), non-target species (Moola et al. 1998; Moola and Mallik 1998), understory species diversity and composition (Mallik et al 2002; Newmaster and Bell2002; Bell and Newmaster 2001) to vegetation management alternatives.