PHYSIOLOGICAL PROCESSES IN PLANTATION ESTABLISHMENT AND THE DEVELOPMENT OF SPECIFICATIONS FOR FOREST PLANTING STOCK

Evidence is discussed that indicates that the stress of transplanting is primarily water stress, resulting from confinement of roots to the planting hole, poor root-soil contact, and low root permeability. These deficiencies are overcome by root growth, a central process in plantation establishment. Root growth depends largely on current photosynthesis, which depends on assimilation of CO2 at the expense of lost water in transpiration. Transpiration is limited by water uptake and hence depends on root growth. Root growth and photosynthesis in newly planted trees are thus mutually dependent. Plant water status immediately after planting, or as soon as conditions favorable to root growth occur, is thus a crucial factor in determining plantation establishment success. Stock characteristics that enhance plant water status immediately after planting are reviewed and the scope for their control considered. -from Author