The development of defect associated with natural branch pruning was 

 analyzed with respect to growth rate and stand conditions using an I.B.M. 650 

 computer. This study showed that by manipulating growing conditions through 

 cutting or improvement work, this defect may be reduced. Additional information 

 of a similar nature was collected in the field on other wound types such as logging 

 scars and fire scars. An artificial wound inducement experiment was commenced 

 in co-operation with the Federal Forest Pathology Laboratory to substantiate these 

 findings. 



Stand structure and basal area studies were started in a stand of hard maple, 

 beech and yellow birch. All trees on a 6-acre block were measured and mapped. 

 Preliminary analysis of this information indicates that useful control guides for 

 timber marking may be developed. 



Preliminary plans are being made to develop a demonstration management 

 area in co-operation with the Parry Sound District. This should provide a useful 

 training and study area for silvics, timber marking, tree grading, stand structure, 

 regeneration and growing stock regulation on some of the major combinations of 

 cover types and land types in the region. 



Yellow Birch. The large quantities of mature yellow birch which occur in the 

 Parry Sound and Pembroke Districts have been available to meet the heavy demand 

 for this valuable tree. However, the paucity of second growth yellow birch timber 

 and the general failure of its regeneration after logging indicated a need to learn 

 its requirements. 



Basic studies have been undertaken to determine the seedbed and light 

 requirements on sites where yellow birch reaches its best development. Knowledge 

 gained from the studies supjxjrts the belief that successive crops may be obtained 

 under suitable conditions. 



Experimental cutting methods have been undertaken and tallies are continuing 

 on plots in the Swan Lake forest research reserve. 



White and Red Pine Regeneration and Growth. This work is designed to 

 evaluate various techniques for establishing regeneration and improving the growth 

 of pine to re-establish the once extremely important pine lumbering industry. 

 Ten-year measurement data were obtained in thinned plots in Pembroke District. 

 A second group of plots, to be remeasured in 1963, will provide the last data 

 required for reporting purposes. Present results indicate the thinning treatments 

 were effective in modifying growth rates. Good growth of survivors occurred only 

 where the heavier cuttings were made. On dry sites important reductions in 

 numbers of natural seedlings occurred with all regeneration treatments. 



An underplanting experiment using white pine is now nine years old. Release 

 of these trees by axe-girdling has indicated that immediate release is most beneficial 

 for all species in terms of growth and survival. 



Tubed Seedlings. The objective of this work is to develop an acceptable and 

 inexpensive method of reforestation which could be useful in extending the planting 

 season and in providing stock for planting immediately after wildfires, and on 

 short notice. 



The survival of tubed seedlings one year following planting has been good 

 (about 90%) and height growth in open plantings was only slightly less than that 

 of nursery seedlings. A small-scale operational planting was carried out in a recent 

 burn, using stock six weeks old. 



SOUTH WESTERN FOREST RESEARCH UNIT 



The research program of this unit is confined to the specific woodlot and 

 plantation problems of primary importance in southern Ontario. For example, 



256 



