POTENTIAL ADAPTATION AND GROWTH OF ORNAMENTAL TREES EVALUATED UNDER THE CLIMATIC CONDITIONS OF QUEBEC AND NORTHEASTERN ONTARIO

Thirty ornamental species and cultivars, grown at eight sites in Quebe c and at one site in northeastern Ontario, were evaluated for hardines s and growth potential over a period of 5 yr. This article presents th e results for four deciduous trees studied: Acer platanoides L., Acer saccharinum L., Malus baccata (L.) Borkh. and Quercus macrocarpa Michx . Overall, all species had a low level of mortality due to cold. Malus baccata and Q. macrocarpa showed a similar potential for acclimation, although their potential for growth differed between sites: M. baccat a could be produced advantageously in any area, while the production p otential of Q. macrocarpa was enhanced by the summer heat of the warme st region. The species with the greatest number of plants suffering wi nter damage was Acer saccharinum, which could not be grown without ris k anywhere in the area studied. Acer platanoides was severely damaged in the coldest of the three biogeographic areas and should not be cult ivated there.