THE GIRTH-INCREASE OF TREES. 107 
No. 17.—BETULA ALBA. 
x | 
| Girth in 
Year. | Apr. |May. |June. | July.| Ang. | Sept. |1stHalf 2nd Half} Inches at 
Observation, 
1892 30 | 50 | 40 | 45 | 5 | 80 90 
| 1808. | 15 | 50 | 35 | 40 | 30 | 10 | 100 80 
| 1894. | 15 | 35 | 40 | 40 | 25] 5 | 90 70 
__ 1806 5 | 2 | 30 | 80 | 30 | 15 | 6 | 75 
| Total, | 35 | 140 | 155 | 150 | 180 | 85 | 330 | 315 
| P.C, | 54 7 24-0 fees 20:2} 54 | 511 | 48-9 | 20 
| : : Two YounG TREES, 1887-91. 
| Pe. | 15 | 15 (325 7 | 19 | 45 | 49 | 51 | 25,14 
No. 17 agrees closely with the other two in the half-season pro- 
portions, which are nearly equal. The chief difference in details 
is that the increase of the first half-season was more equably dis- 
tributed in No. 17 than the others. The former was much quicker 
in growth, so that all the highest scores occur inits records. They 
are April 15, May 50, June 50, July 40, August 45, September 15. 
A much larger Birch, at Craigiehall, five feet in girth, and 
growing at the rate of half an inch yearly, gave quite different 
and altogether anomalous results. During the six years’ obser- 
vations it had no increase whatever in April and May, the only 
instance in any tree of any kind I ever met with. Consequently 
the proportion of the first half-season, confined to the single month 
of June, was only 27 p.c. With all this the tree seemed quite 
healthy. 
No. 11.—CRATAGUS OXYACANTHA. 
Girth in 
1st HAlf |2nd Half} Inches at 
Year. | Apr. | May. |June.| July. | Aug. | Sept. | coocon | Season. 
Observation. 
1892. Soe ee eee 5 45 55 
1908 [28 ase) Bacio ae 4 SS 5 55 55 
1894. ae ee Se ae 40 45 
1895. ib ae ee bo oo 7 IS tT a 40 60 
Total, | 10 | 40 [130 | 110 | 75 | 30 | 180 215 
PC, 25 | 10-0 | 33:0 | 279 | 190 | 76 | 45% | 54°5 14 
One Younc TREE, 1887-91. 
i 
| P.C, 45 | 95 | 2 992 us| 42 | 58 | 15 
24°5 
