THE GIRTH-INCREASE OF TREES. 105 
Although only one Willow was under observation, the results 
are probably among the most reliable of all, from the large incre- 
ments all through the nine years. The tree also has been steadily 
under chservation for the long period of nine years, which 
enables a comparison to be made between three years of infancy 
and six of youth, observations having been begun when it was a 
mere wand, an inch and a half in girth, and continued till it 
measured two feet. It will be seen from the Table that there is 
scarcely any difference in the monthly percentages between the 
earlier and later stage, a larger proportion for April in the later 
stage being alone noticeable. The second half-season pre- 
ponderates in the large proportion of above three to two. No 
single menth has the mastery, July and August being equal, 
and June not much behind them, September is unusually high, 
and thus the increase is more equably distributed over the 
growing season than in any other species. 
Very high individual scores are numerous. Three times, once 
in June and twice in August, the tree nearly accomplished a 
score of an inch, but perhaps the record of nearly three-quarters 
of an inch in September of 1895 is more remarkable. The 
highest records for each month are :—April, 25; May, 55; June, 
95; July, 85; August, 95 ; September, 70. 
No. 9.—POPULUS FASTIGIATA. 
| Girth in 
1st Half |2nd Half} Inches at 
Year. Apr. | May. | June, | July. | Aug. | Sept. Sanaier Gaaaah. ee 
| Observation. 
| 
1892 10 | 2 | 55 | 30 5 35 90 
1893. 15 | 45 | 50 | 25 60 75 
1894 SB 1.-10 | 38 | is 88 30 75 
1895 15 | 45 | 40 | 30 60 70 
| Tota, | 5 | 50 | 130 | 185 {120 | 5 | 18 | 870 
| 
P.C. - | 10 | 10-1 | 26-4 | 37:5 | 24 | 10 | 875 | 62% 14 
Two Younc TREES, 1887-91. 
P.O; | 1 | 8 | 208 34°5 | 38 | 3 | 29°5 | 70°5 | 14, 12 
