Water table levels, soil moisture content, soil water poten- 

 tial', and radial growth of red pine were measured through- 

 out the growing season. 



Silver maple seedlings with divided root systems were 

 grown in nutrient solution culture for a study of the effect 

 of non-uniform moisture availability. 



Analysis of radial and length growth in the stem and root 

 systems of four 33 year-old, 46-foot-tall red pine was com- 

 pleted. Maximum length of roots approximated 23 feet. 

 Average roots grew 16 feet in the first 12 years. Radial growth 

 usually declined after 10-15 years following crown closure 

 and increasing distance between roots and their carbo- 

 hydrate supply. 



TREE NUTRITION UNIT 



Studies were conducted in the greenhouse and nursery beds 

 to develop methods of fertilizing young outplanted trees on 

 adverse sites. Changes in the foliar nutrient concentration 

 and growth of container-grown trees, outplanted to a nur- 

 sery site, are being examined to establish bench marks. 



Fertilization trials, in conjunction with annual growth 

 measurements at various heights on the bole, were carried 

 out. These measurements are being taken on black and 

 white spruce, jack and red pine, and sugar maple to obtain 

 comparative growth rates of different sizes and the annual 

 volume increase. 



Sample plots were established in natural stands of trem- 

 bling and large tooth aspen in the Madawaska Valley to 

 study the growth and type and degree of defects. Studies 

 will determine whether the defects are due principally to 

 poor nutrition or to other factors such as frost damage, root 

 fungi or rodents. 



ENVIRONMENTAL PHYSIOLOGY UNIT 

 The aims are to determine the effects of various environ- 

 mental factors on the physiological processes of trees, and 

 to assist and improve nursery procedures and practices by 

 the implementation of the findings. 



Emphasis is placed on determining the varying degrees 

 of frost hardiness and dormancy of our native coniferous 

 species throughout the year, and the development of 

 methods of determining these characteristics. Indications 

 are that during certain periods of the year, under natural 

 conditions, the degree of frost hardiness is related to the 

 degree of dormancy. 



FOREST ECOLOGY UNIT 



Studies continued on yellow birch and sugar maple relating 

 to the optimization of the growth and development of 



established yellow birch regeneration and with character- 

 ization of sugar maple defect especially with regard to fac- 

 tors which regulate defect syndrome development. 



Additional evidence for the strong interaction between 

 overhead and lateral competition, and their joint effects on 

 height and diameter growth and the form and quality of 

 yellow birch saplings, was obtained. 



Tentative evidence for the adverse effects of high light 

 intensity, on internode elongation of yellow birch germina- 

 tion, was gathered in a growth room experiment. 



Occurrences of bole damage due to insects and to frost 

 cracking show definite chronological trends which are being 

 compared to climatological data to determine the specific 

 ecological conditions under which such high incidences 

 occur. 



Winter sunscald was studied in relation to intensity of cut 

 in a drumlin-situated stand with severe damage level. 



WOOD SCIENCE UNIT 



Investigations aim at defining the specific physical and 

 chemical vsood characteristics which contribute to the supe- 

 rior quality of the manufactured products, and to relate 

 their characteristics to heritable and environmental factors. 

 The principal species has been black spruce with new em- 

 phasis being directed to develop a program on poplar in 

 co-ordination with the Tree Breeding Unit. 



A contractural arrangement with the Ontario Research 

 Foundation allowed that organization to conduct research 

 on the anatomical and chemical properties of wood. 



The Faculty of Forestry at the University of Toronto has 

 initiated studies at the post-graduate level in conjunction 

 with Research Branch and the Foundation. 



SEED UNIT 



Studies continue of the effects of physical seed characteris- 

 tics on the growth of seedlings. Included are investigations 

 of the variability in growth and yield related to seed source, 

 and management problems involved in production of seed 

 on selected sources of phenotypically superior stands. 



Practical improvement in seedling growth due to separa- 

 tion of seed on the basis of physical characteristics was 

 obtained for black and white spruce and jack pine, at a 

 maximum shippable size for tubelings. 



There is strong indication from experiments carried out 

 for the spruces and jack pine, under greenhouse conditions 

 at least, that germinative energy is related to subsequent 



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