l62 TRANSACTIONS OF ROYAL SCOTTISH ARBOKICUI.TURAI, SOCIETY. 



Planiation I. 



Sco^s Pi lie. — Observations of five trees. 



Circiimtor- 

 ence over 



b.irk I St May 



I 1911 



Averacje 



32 68" 

 29-50" 

 38 12" 

 3063" 

 33 '50" 



;2-S8" 



% 1911 

 % 1910 



24 



43 

 38 



14 

 19 



100 

 100 



= -'-59 -l. 



Estimated number of 

 stems per acre 220. 



Average total 

 height 36'. 



Reference was made last year to the considerable variation 

 in the growth of individual trees. The second season's observa- 

 tions are of considerable interest in this respect. The figures 

 show that generally speaking there is a corres[:)ondence in the 

 results, individual trees which made good growth in 1910 having 

 maintained their position in 191 1, and vice versa. 



A comparison of the average figures obtained for each plot 

 in the two seasons shows a variation which is almost certainly 

 attributable to the dry and warm summer. It may be remarked 

 in passing that the district, while enjoying a full share of the 

 fine summer and autumn, was also favoured with a fair rainfall, 

 and that for only two comparatively sliort periods was there 

 any actual drought. 



It will be noticed that in practically every instance the 

 {percentage of growth in May was higher than in 19 10, while 

 in every case excei)t that of Plantation K (Scots pine) the total 

 season's growth was rather less than in 1910. The results 

 obtained in the latter plantation are somewhat remarkable. 

 In i9ro the whole girth-increment, averaging -350 inches, was 

 laid on in June and July--25 in the former and 75 % in the 

 latter month, the percentage rate of growth being 4-24 %. In 

 1911 the girth-increment averaged -450 inches, and was laid 

 on over a period of )io less than five months, from May to 

 September, the proportion of the season's growth in the month 

 of May being as high as 30 %. The percentage rate of growth 

 also rose to 4-75 %. It was remarked last year that the short 



