Tree Nutrition » Forest Disturbance and Regeneratlofi . 



Studies are under way on the effects of prescribed burning and 

 scarification on nutrient release in the soil and the uptake of these nutrients 

 ; and the growth of tree seedlings. Part of this work is being co-operatively 

 studied by the Division of Forest Biology, Canada Department of Forestry, to 

 ascertain the effects on the microbial population of the soil. 



Red Spruce Ecology . 



This tree has characteristics which may be useful in improving the 

 productivity of derelict tolerant hardwood and mixed-wood stands. Studies de- 

 signed to measure its productivity on different sites in pure and mixed stands 

 across its range are being carried out. It is hoped to provide explanations of 

 differences in spruce growth in terms of nutrient uptake from the soil. Work is 

 also proceeding in the examination of different strains for the best ecological 

 characteristics. A large scale experimental underplanting has been established 

 which should provide information useful in silvicultural practice and of a funda- 

 mental nature on shade tolerance. 



Smelter Fume Pollution . 



In the vicinity of Sudbury, Cutler and Wawa, large areas of forest 

 have been removed from forest productivity due to effects of smelter fumes. The 

 research officer and a member of the Botany Department, University of Toronto, 

 who was hired for the summer, have carried out studies at both Sudbury and Wawa on 

 the fallout from the smelter fumes and the effects on forest soil, lake waters, 

 aquatic and forest vegetation. Two papers have been published. 



South-Central Region 

 Forestry research in the South-Central Region is aimed primarily at 

 developing investigative methods to study quality and growth performance of 

 tolerant hardwood species in relation to environment. 



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