Ecophysiologie du pin blanc (Pinus strobus L.) en plantation soumis a des traitements sylvicoles intensifs

The impact of intensive silvicultural treatments and competition on leaf level morphological and physiological response of Pinus strobus L. saplings was studied. Herbicide application and scarification had a significant positive impact on eastern white pine saplings. The foliage of eastern white pine showed a certain capacity to acclimate to conditions of competition (and shade). Leaf nitrogen and leaf-dry mass per unit area were both driving variables for leaf level-photosynthetic capacity of saplings, whether there is competing vegetation or not. Soil temperature proved to be an important environmental factor for the establishment of young eastern white pine. The effects of foliar absorption of dew by eastern white pine seedlings were also investigated in a greenhouse experiment. Dew significantly increased shoot water potential, stomatal conductance and seedling root growth. This finding has practical implications for field studies of water relations of eastern white pine.