Reservation. 



On another page in this report will be found a study of the 

 rate of tree growth in respect to diameter and volume. This shows 

 that for a given time that the different species of trees, as well as 

 the individuals of the same species, vary considerably in diameter 

 and volume. "Why this variation? The answer to this question 

 is valuable to the man who expects to plant forest trees and to 

 the woodlot owner. They are interested in knowing which species 

 of trees grow the fastest and will produce the greatest amount of 

 merchantable wood products in a definite period. 



However, as yet we have only an imperfect knowledge of how 

 to make our forest trees produce the most in the shortest space of 

 time. Additional information is desirable, which must be obtained 

 by experiments which will extend over long periods of time. The 

 habits of each species of trees are fixed by heredity, and man, in 

 cultivating them, is obliged to meet the requirements of each spe- 

 cies or change their habits by breeding. 



Many experiments are now in progress at the forest experi- 

 ment station, in which the habits of many species are being studied 

 and an effort is being made to discover the laws of tree growth. 

 The different species are studied as units, and the several species 

 are contrasted and compared. 



The experiments now in progress are for the most part to de- 

 termine the relation of the more important species to soil and 

 moisture conditions; the effect of pure and mixed stands; the 

 effect of spacing on the rapidity of growth and quality of product ; 

 the kind and amount of pruning that should be done; the effect 

 and value of cultivation. The results of the above experiments 

 must be deferred for future reports, since they have not been in 

 progress a sufficient time to warrant conclusions. 



Several auxiliary experiments have been undertaken which 

 will take several years to complete. Since a preliminary report 

 was made last year on the experiment to determine what time of 

 the year the several species of trees make their growth, the data 

 obtained this year on this experiment are here given, 



[2—28415] (15) 



