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THE ESSEX NATURALIST
become a common conifer in this country, to which it was intro-
duced a little more than 100 years ago. It has been extensively
planted here as a plantation tree and home-grown Douglas Fir
timber is now well known., particularly by reason of its wide
growth rings. The tree seems to have taken kindly to Britain
and sets seed here; it may even establish itself naturally. What
it can do in Britain there has not yet been time to discover, but
trees 50 years old may rise to over 100 feet in favoured localities
and Ackers (1947) claims that healthy Douglas Fir only begins
to grow after it is 40 to 50 years old. . Douglas Fir is a tree which
is favoured by a high rain-fall and which is likely, therefore, to be
more common on the western side of Britain. It wants a some-
what sheltered position because its leading shoots tend to be
damaged or broken by the wind ; one writer has suggested that
woodpigeons alighting on leading shoots may do as much damage
as wind.
Another of these American invaders is the Sitka or Silver
Spruce (Picea sitchensis Carriere), and this is a tree which is likely
to become more prominent in our English landscape, for it is
one which has found favour with the Forestry Commission and
in the west it will probably replace the Common Spruce. It may
well provide an important source for pit props in our coal mines
in the future. The tree seems to thrive here, although we do not
yet know how big it will grow, for it has only been growing in
Britain for a little over a century; even so, there are trees which
are 120 feet high and five feet in diameter.
Two of the North American silver firs are also being tried out
experimentally in plantations and may become features of our
countryside in years to come. These are the Giant Fir (Abies
grandis Lindl.) and the Noble Fir (A. nobilis Lindl.), the former
producing a very heavy yield of timber and being characteristically
free from disease, the Noble Fir yielding a wood which for silver
fir is of good quality.
Many more conifers ought to receive consideration, were I to
deal with popular ornamental trees, but I will refer only to three
more, all from western North America and all being tried
out experimentally in plantations—the Californian Redwood
(Sequoia sempervirens (Lamb.) Endl.), Lawson's Cypress or Port
Orford Cedar (Chamaecyparis Lawsoniana (A. Murr.) Parl.)
which is probably also the commonest cypress grown as an
ornamental tree in this country, and Western Red Cedar (Thuja
plicata D. Don.). All three trees yield rather soft but very
durable woods. Western Red Cedar, with its tapering trunk
and red-brown stringy bark, would certainly add variety to our
landscape, as would the redwoods, if and when they had attained
the colossal dimensions of the North American sequoias.