ANNUAL INCREMENT OF SPRUCE AND SCOTS PINE. 



55 



As might be expected there is considerable variation in the 

 growth of individual trees, and after another year's observations 

 it will be possible to ascertain whether these variations are 

 constant. 



One of the most striking results obtained is in Plantation K, 

 where the whole increment growth was made in the months of 

 June and July, whereas in the other plantations growth extended 

 from May to September. It is not unnatural that on a poor, cold 

 soil the commencement of the season's growth should be delayed 

 by three or four weeks as compared with more favourable 

 situations. It is not so apparent, however, why growth should 

 stop in July, when there would appear to be still another four 

 or six weeks of favourable conditions as regards temperature 

 and moisture. 



It will be noticed in Plantation I, where the spruce and Scots 

 pine are the same age and growing under identical conditions, 

 that the growing season of the latter seems decidedly shorter by 

 fully a month. 



The results obtained from a single season's observations are 

 perhaps not sufficiently definite or accurate to enable exact 

 conclusions to be drawn. It may be of interest, however, to 

 compare in each case the estimated growing stock, the mean 

 annual increment, and the current annual increment, as revealed 

 by the measurements taken. The figures given represent, in 

 every case, quarter-girth measurement over bark. 



In every case, it will be observed, there are too few stems per 

 acre, and the density might be better. This seems to be 

 partly due to thinness in the original crop, and partly to 

 subsequent overthinning. There is no record of what has 

 been obtained in thinnings, but in the case of Plantation I, at 

 any rate, the mean annual increment would be somewhat larger 

 if thinnings were taken into account. The results obtained are 



