THE GIRTH-INCREASE OF TREES, 55 
infancy. Deducting the year 1888, which appears to have been 
unusually unfavourable to Nos. 71 and 74, the range of these 
two and of No. 16 in eighteen records was moderate, 1°00 
16. FUE. 
ACER CAMPESTRIS. 
This young Maple, No. 12, at the N.-W. corner of the 
Arboretum, has only been under observation since 1892, and its 
increments have been 1°60, 1°30, 0°85, 1°55, 100, and ‘90, 
giving an average of 1°20, the girth being now twenty inches. 
Since 1896 the tree has not looked so healthy as at first, possibly 
the result of pruning, although it was not excessive. The 
increase has been very erratic, and the range, 85 to 1°60, is high 
for so short a period. 
CESCULUS HIPPOCASTANUM. 
ANNUAL INCREMENTS. 
Av. : 
Total. ne 
Ist 
Decade 1998, | 1889. | 1890. | 1891. | 1892. | 1893. | 1894. | 1895. | 1896. | 1897. 
1°65 | 16 | 53°75 
33 ia es) 10 00 | 259 10 | 25}; 25) 30) 00 
70.| 1:10 | 90] *80 | 85 § 90 | "75 | “60 | ‘25 | °60 | 660 | ‘82 | 11°85 
1°05 | 1°35 | 1°30 | 1°15 | *10 | *40 | “55 | 1°25 | 1°25 $5 $8°30 | 1°19 | 15°45 
1:35 [1°40 | 105 | 105 | °75 | -60 [4°85 | 1-21 | 19°00 
aed oC | No. in List. | 
No. 9, the only Horse Chestnut observed in the first decade, 
was somewhat crowded, but had a fair head of foliage, and was 
four feet in girth. In 1878 the girth-increase was 0°70, but it 
suffered a decided fall from the very low temperatures of the 
next two winters, only to rally again to 070 in 1881. Next 
year, from some cause that affected the species universally near 
Edinburgh, the foliage withered in May, but it revived next year, 
and has been dense and healthy ever since. Nevertheless, the 
average increase for the six years following 1882 was only 0°17, 
and for the next ten 016. In twenty years it has increased 
only five inches. Is the singular fact of apparent healthiness 
and vigour, along with an extremely low rate, the prolonged 
effect of the disease of 1882? Or may it be due to the over- 
cd 
