1088 ARBORETUM ET FRUTICETUM 
of the tree is slow when young, but 
rapid after it has attained the age of 
10 or 12 years. Cones with fertile 
seeds are seldom produced before the 
tree has attained its 40th year ; though 
cones without seeds often appear be- 
fore half that period has elapsed. The 
female catkins are often produced for 
years together, without any males ap- 
pearing on the same tree. Young 
trees are apt to lose their leaders by 
very severe spring frosts; and, hence, 
we frequently find old silver firs with 
forked trunks and branchy heads. The 
wood of the silver fir is elastic, and the 
1938. P. pectinata. 
colour is whitish. The grain is irre- 
gular, as the fibres which compose it 
are partly white and tender, and partly - 
yellow, or fawn-coloured, and hard. 
The narrower the white lines are, the 
more beautiful and solid is the grain 
of the wood. The wood of a tree 80 
years old weighs 66 lb. 1402. per 
cubic foot green, and 41 lb. 5 oz. when 
dry ; while that of a tree 40 years old 
weighs only 37 lb. 90z. when dry. It 
shrinks considerably in drying, like all 
white woods. It is used for planks 
and carpentry of all kinds, for the 
masts of small vessels, for joists and 
rafters, and for building the boats 
used for navigating rivers. It is said 
to endure a long time when used as 
piles, and to be much employed in 
Holland for that purpose. From the 
resin of this tree are manufactured 
Strasburg turpentine, colophony, and 
white pitch. The silver fir, like all the 
other Abiétine, will attain a large size 
BRITANNICUM. 
“1959. P. pectinata. 
on soils of a very opposite description ; but a loam, rather rich and deep than 
otherwise, appears to suit it best. 
The silver fir requires a low situation, 
comparatively with the spruce fir, not being nearly so hardy as that tree, either 
when in the nursery or full grown. The cones, which are produced in abun- 
dance in Britain, are apt to shed their seeds in spring ; they ought to be gathered 
in October or November, and kept in a dry place till the sowing season. The 
