164 FORESTS, WOODS, AND TREES 
a distinct geographical area characterised by wild forests of 
Scots pine and of Betula verrucosa. 
(2) Red birch (Betula pubescens), with hairy twigs and 
spreading or ascending branches, is found on wetter soils 
and in moister climates than the silver birch, and is the 
prevailing species in Ireland and the west of Scotland. It 
is a more rigid tree, of less size, and with a darker bark. 
It will grow on marshy ground and wet peat, but of course . 
under such circumstances is only a small tree. 
Birch is useful for temporary fencing, and lasts a long 
time when creosoted. It is also valuable for pitwood, 
furniture, bobbins, spools, ete. 
Poplar.—Of the numerous kinds of poplar, those of 
interest to the forester are grey poplar, aspen, and black 
Italian poplar. 
1. Black Italian poplar (Populus serotina) is of hybrid 
origin, being the result of a cross between the European 
Populus nigra and the American Populus deltoidea, two 
wild species. Black Italian poplar is always propagated 
by cuttings or sets, and bears male flowers. It is the latest 
of all the poplars in coming into leaf. Its hybrid origin 
accounts for its astonishing vigour, Grown in the open, it 
produces a larger volume of timber and comes to maturity 
earlier than any other broad-leaved tree in this country. 
In good situations, it reaches 100 to 120 feet in height 
in 50 or 60 years, a single stem often containing 100 
cubic feet of timber at that age. It grows freely in 
most soils, and is extremely hardy, resisting frosts at all 
seasons. Except in sheltered positions, it suffers from wind 
in Ireland and on the western seaboard of Scotland and 
Wales ; but in England and in the other parts of Scotland and 
Wales it bears a fair amount of exposure. The main value 
of the tree lies in its capacity for growth in situations and 
soils where ordinary trees fail. It succeeds in cold, wet, 
and undrained valleys and meadows; and thrives even on 
wet clay, provided the stagnant water is drained off. It 
grows well on shallow bogland and on gravelly soils. 
