1888-89.] Annual Increase in Girth of Trees. 407 



diminution did occur after the loss of its top-shoot in the 

 same winter, but there were other causes of failure. 



2. Density and healthiness of foliage are not necessaril}- 

 proofs of rapid growth. The most striking example of this 

 occurred in the lime at Craigiehall, a perfectly healthy look- 

 ing tree, well clothed with foliage every summer, which 

 nevertheless increased in girth at the ainiual rate of only 

 about one-sixth of an inch in ten years. But other examples, 

 almost equally remarkable, may be quoted, such as the two 

 younger limes and the young sycamore in the Botanic Garden. 

 It does not follow, however, that a tree should be condemned 

 for slow grow^th near the ground, as it may be adding sub- 

 stantially to its timber higher up. 



3. Unusual density of foliage in a tree does not necessaril}' 

 imply quicker growth than in other trees of the same species 

 and age. Thus the density of foliage in the beech No. 8 is 

 nearly every year twice as great as in its neighbour No. 7, 

 a tree of about the same age, yet the latter grows somewhat 

 quicker than the former. 



4. Early foliation does not necessarily produce greater 

 growth. This is illustrated by the two trees just mentioned, 

 as No. 8 comes into leaf from ten days to a fortnight sooner 

 than No. 7, yet grows a trifle slower. 



5. We cannot with safety conclude that a tree is increasing 

 well in girth merely from its healthy appearance. This 

 follows from conclusions 2, 3, and 4. 



6. It is only by measurement that we can ascertain 

 positively whether a tree is increasing in girth rapidly or not. 

 But measurement for a single year only is insufficient, and 

 even for three years, as suggested by Sir Robert Christison, 

 may be misleading. The great annual range in the girth- 

 increase of almost all the trees proves this in a general way. 

 But taking particular examples : — For a period of three years 

 we may select beech No. 7, which grew at the rate of 0"81 

 from 1879 to 1881, and at the rate of 117 from 1884 to 

 1886 ; and for single years — avoiding the three consecutive 

 bad seasons when extreme differences might may be expected 

 — we may quote the horse chestnut No. 9, which increased 

 0-70 in 1882 and only 0-05 in 1885, although in both years 

 the foliage seemed perfectly healthy, and the sycamore No. 

 28, which grew 0-55 in 1884 and only 0-20 in 1887. These 



