growth and that germination conditions and seed treatments 

 have a marked effect upon germinative energy. 



TREE BREEDING UNIT 



The work of the unit continues to concentrate on four major 

 projects: poplar and spruce breeding, white pine breeding, 

 and hard pine breeding. 



The best selections of hybrid and native poplars were 

 propagated and field tested. A major pilot project was in- 

 itiated in co-operation with Timber Branch for poplar pro- 

 duction in short rotations in southeastern Ontario. 



Twenty-three superior trembling aspen and cottonwood 

 trees were selected from native Boreal Forest stands and 

 from southern Ontario. They were established at the Maple 

 nursery for testing purposes. One hundred and ninety-five 

 superior new hybrids were also selected at Maple for clonal 

 propagation and testing. 



The best 58 aspen hybrid clones, observed and propagated 

 for three years, were selected for larger-scale propagation 

 and field testing. The selected clones demonstrated excellent 

 performance and showed a consistently good rooting ability 

 of stem cuttings. 



As new spruce hybrids are obtained, it becomes possible 

 to compare their performance and relate this to the planting 

 stock currently used. Several experiments were started last 

 winter, and results of preliminary nursery measurements for 

 some of the hybrids are favourable, but field performance 

 will be the criterion used to judge their value. 



In order to confirm the hybridity of interspecific hybrids, 

 it is essential to readily identify a species or hybrid at an 

 early age. A technique developed of examining cross- 

 sections of primary needles seems promising. 



Vegetative propagation trials have produced good results 

 in rooting of spruce. 



White pine studies were concentrated on developing and 

 testing Pinus griffithil x P. strobus hybrids, on vegetative 

 propagation, and on blister rust testing of the progenies of 

 putatively resistant trees. 



Significant progress was made in vegetative propagation 

 of white pines. Good rooters were found among the tested 

 trees, and the development of white pine clones is 

 anticipated. 



FORESTRY ECONOMICS UNIT 



The Unit's aim is to assemble, analyze and develop eco- 

 nomic information which may be combined with biological 

 findings in subsequent practical implementation. 



McCullough Lake sample plot area. May, 1970, showing re- 

 generation in a 50-foot wide plot heavily thinned in 1961 . 

 The basswood was planted: the white ash is natural. Photo 

 by T. Jenkins. 



"-if 



