regeneration. It includes studies of the ecology of red spruce, and work on smelter 

 fume pollution in relation to forest soils and vegetation. 



Tree Nutrition, Forest Disturbance and Regeneration. These studies are 

 designed to provide explanations for such questions as why some tree seedlings 

 grow better than others as a result of different types of scarification, and whether 

 or not repeated prescribed burning has a detrimental effect on forest soils. 



Studies are under way on the effects of prescribed burning and scarification on 

 nutrient release in the soil, and the uptake of these nutrients on the growth of 

 tree seedlings. 



Productivity Ecology of Red Spruce. The red spruce tree has characteristics 

 which should prove very useful in improving the productivity of derelict tolerant 

 hardwood and mixed-wood stands. The study is designed to measure the growth 

 and productivity of red spruce in pure and mixed stands on the complete range 

 of physiographic sites across its range in Ontario. 



Information derived from this study should prove useful in studying all 

 spruces, and comparative measurements are being made on white and black spruce 

 when these species occur in association with red spruce. 



It is hoped to provide explanations of differences in spruce growth as related 

 to nutrient uptake from forest soils. In addition, total productivity (dry weight 

 production) and ground flora relationships are being investigated. 



This is probably the first time in Canada that foliar sampling and analysis 

 of tall trees is being attempted. It is hoped to make use of the most modem 

 techniques available, such as computer programming in working up the data in 

 order to save time and obtain the most definitive information. 



Work proceeding on the genetic variation in spruce includes the examination 

 of different strains for the best ecological characteristics. Early indications are 

 that natural or artificial hybrids between red and black spruce, while possibly 

 possessing some hybrid vigour, are not nearly as desirable as the parent species. 

 The hybrids are exceedingly rough and limby. A large scale experimental under- 

 planting has been established, and assistance to the Timber Branch on the establish- 

 ment of seed production areas is continuing. This includes the location and 

 demarcation of suitable spruce stands, and the selection of the trees to be used for 

 release and subsequent seed collection. 



Smelter Fume Pollution. The objective of this study is to provide information 

 on the nature of smelter fume damage and its effects on forest vegetation, forest 

 soils and waters as a prerequisite for suggesting means of jx)llution control and 

 the best means of forest land management under the circumstances. 



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

 Toronto, have carried out studies at both Sudbury and Wawa on the fallout from 

 mine ore smelter fumes and the effects on forest soil, lake waters, aquatic and 

 forest vegetation. A series of four papers on this subject has now been published. 



SOUTH CENTRAL FOREST RESEARCH UNIT 



Most of the research effort has been directed towards the major commercial 

 species in this region: white and red pine, hard maple and yellow birch. 



Sugar Maple Growth and Quality. Studies are being conducted to show how 

 defect is associated with growth or growing conditions and to define the conditions 

 under which suitable growth and quality of sugar (hard) maple can be attained. 



Cross sections of sugar maple trees which were felled commercially were 

 obtained for tree development studies. Growth measurements taken from these 

 samples indicated that tree quality was dependent on continued rapid growth. 

 Defects and decay tend to be associated with slow growth. 



255 



