Central Unit 



The research work includes growth studies of commercial species in the 

 central portion of Ontario. 



The main study at the present time is on the usefulness of red spruce to 

 improve the quality and value of the cut-over hardwood stands. All spruces are 

 receiving attention in this work. Laboratory and field studies are being made of 

 the ecology of spruce species, and the racial variation of the spruce genus in 

 relation to growth and relative efficiency in nutrient uptakes. 



Particular attention is being given to red spruce, which has characteristics 

 which make it very useful in improving the productivity of derelict tolerant hard- 

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

 productivity of red spruce in pure and mixed stands on all physiographic sites 

 across its range in Ontario. Some emphasis was given in 1965 to a comparison of 

 white and black spruce where these species occurred on the same sites as red 

 spruce. 



In addition, studies were continued on the effect of prescribed burning and 

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

 on the growth of tree seedlings on different landtypes. 



South Central Unit 



The objective of this Unit is to provide information for the management of 

 the important commercial tree species that occur in this region — sugar maple, 

 yellow birch, red and white pine. Work is done on problems of regeneration, 

 growth and quality of these species. 



STAND CONVERSION — TOLERANT HARDWOOD TO MIXEDWOOD 



A trial was established to study and demonstrate the effectiveness of using 

 prescribed burning in the preparation of an area for planting coniferous species. 

 A block of low-quality hardwoods growing on a shallow soil was treated in the 

 fall of 1963 and in the fall of 1964 by burning the fallen leaves. This greatly 

 reduced the numbers of hardwood seedlings and saplings which normally interfere 

 with the growth of planted trees. Leaving the better quality immature trees, the 

 stand was cut to recover merchantable logs from the mature and poor-quality 

 trees. The openings thus created were planted, according to local soil conditions, 

 with white pine, red pine, white spruce, basswood and sown with acorns of red 

 oak. Additional felling of low quality trees was done to provide better light 

 conditions for the planted stock. 



STAND IMPROVEMENT — TOLERANT HARDWOODS 



Detailed information on stand structure and tree quality was obtained from 

 five, twenty-acre blocks of hardwoods which had been lightly cut some forty years 

 previously. This information was used to prepare a plan for improvement cutting 

 trials to be carried out in co-operation with the Timber Branch. A computer 

 programme was prepared by the Mathematics Unit and was used to facilitate 

 compilation in this project. The use of this programme for similar projects in the 

 future will be of great advantage. 



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