THE GIRTH-INCREASE OF TREES. 117 
by comparison, all that can be done is to give the results in the 
same tabular form as in the other two classes, and although there 
is a considerable variety in their reliability it does not seem to 
be practicable to divide them into categories in that respect, and 
it will be sufficient to point out the species which appear to be 
most worthy of confidence, as we go along. 
Apr. | May. | June. | July. | Aug. | Sept. lst Half pve Half 
Robinia Pseudacacia, .../ 6 | 9°5 | 16 |25 | 34 | 105 | 305 | 69% 
Quercus rubra, .| 85 | 11 | 225 | 3865 | 25 15 | 387 63 
BaliS tps | 25 }14 |21 |26 |265}10 | 375 | 625 
Acer campestris, = 3 {12 |29 |82 |215| 25] 44 | 56 
Ulmus campestris, ' 4 {105/986 {29 [17 | 6 | 48 | 50 
Quercus Cerris, | 75 | 18 | 245 | 815 | 16 | 25) 50 | 50 
| a3 ]155]33 [27 (155 | 75 | 50 | 50 
Pyrus communis, 
The Rodinza, always in good condition, growing consistently, 
and under observation for six years, may be considered reliable 
for so very young a tree. It threw no less than 70 p.c. of its 
Increase into the latter half of the growing season, surpassing in 
this proportion all my other trees, save Leriodendron tulipiferum, 
another native of sunnier climes, in which the proportion rose to 
90 p.c., but which does not appear in the Table, as it is an old 
tree 
If results in any single tree may be relied on as representative 
of its species, our Sa/éx may make the claim, owing to its large 
increments and the regularity and consistency of its conduct 
during the long period of nine years. 
Quercus rubra and Q. Cerrts are not quite so favourably 
situated, as although they are fine, healthy trees, growing at good 
rates, they were somewhat erratic in conduct, due perhaps to 
extreme youth. Q. Cerrts also disagrees with the two adult and 
very fine trees that were under observation in the earlier period. 
Ulmus campestris and Acer campestris are species that can 
scarcely be said to thrive in Scotland, and the example of Pyrus 
