174 CHRISTISON—-OBSERVATIONS ON 
2. Distribution of the girth-increase over the growing 
season in the younger Conifere, ... 190 
53 eee. increase and decrease in jee growing 
seaso eee 
4. cca with a Tetras group of ae same ‘ 
period, ave : a = IgI 
THE Conifer under observation have not thriven so well as the 
Deciduous trees, not from a faulty selection, but owing to general 
causes affecting all of the tribe in the Garden. Poverty or 
incompatibflity of soil may be the main cause, but not impro- 
bably increasing influences of town atmosphere contribute to the 
evil. That the nature of the soil is not the only cause is 
indicated by some pines having attained a size and beauty, when 
our observations began more than twenty years ago, such as 
none of the younger trees now coming forward give promise of 
reaching; and that the Conifer are extremely sensitive to Edin- 
burgh atmosphere, so that they might possibly be affected even 
by the present comparatively slight. town-surroundings, seems 
proved by the almost total absence of pines in the city gardens, 
and the miserable appearance of the few that are to be seen. 
Another contributory cause, in some of the pines under observa- 
tion, has been overcrowding in the Pinetum, which, owing to the 
stress of more necessary work in rearranging the Gardens of late 
years, could not be dealt with in time to prevent injury. 
The only species that has thriven well in the past, and continues 
to thrive well still, is the yew, but not a few other species have fared 
not badly up to and from the 15th to the 25th year of life, some 
individual trees to even a considerably greater age. To these, 
therefore, I shall mainly confine my attention, beginning, as in 
the Deciduous class, with the history of the species separately, 
although, unfortunately, except with a few, it is not possible to 
follow them out in the same manner, tracing the old trees from 
decade to decade and comparing them with younger sets in the 
second decade, because nearly all the Conifere of the first 
decade disappeared or became ineligible near or soon after the 
expiry of that period, and because there was no such difference 
in age between the sets in the Coniferze as in the Deciduous 
class. : 
