Not to be semantically confused with : Hemlock (Conium maculatum), Hemlock Water-Dropwort (Oenanthe crocata) [some very poisonous plants with similar names]
Easily mis-identified as :
Eastern Hemlock aka
Eastern Hemlock-spruce (Tsuga canadensis) the main differences being that the reverse sides of the flat narrow leaves of Western Hemlock have two slightly wider whitish lines and the sides of the leaves of Western Hemlock are more or less parallel with any widest part in the middle whereas in
Eastern Hemlock they taper sightly towards the ends with the widest part nearest the shoot and its leaves are lemon scented. Like Western Hemlock, there is a second pair of leaves above the first, but on
Eastern Hemlock the upper leaves are shorter and reversed (upside down!). Also the trunk in
Eastern Hemlock often forks into several smaller trunks on its way up. The cones of Eastern Hemlock are smaller at only 18mm long whereas they are 25mm long on Western Hemlock. Also, new shoots (leaders) on
Eastern Hemlock do not droop or drape.
Can be mistaken for several differing fir trees such as
Douglas-fir (Pseudotsuga menziesii) (which is not a fir) but the leaves of Western Hemlock have distinctive stalks and the female cones are small (about 15-25mm long) and egg-shaped and has short dark-green and shiny leaves. The drooping curtain-like leafy shoots draping from the ends of main branches are also quite distinctive.
Possibly mistaken for :
Brewer's Spruce and for European Larch (Larix decidua) which both have long dangling leafy shoots.
It is frequently planted in coniferous plantations often with other hardwoods.
Western Hemlock is a coniferous evergreen tree and grows to a height of about 46m, taller than
Eastern Hemlock and was introduced and subsequently naturalised in the UK. Many Western Hemlocks in America grow to 70m, the record being 83m but even half that height worries your Author, for the roots are quite shallow not far below soil surface. Moreover, it was sold to him as a tree which grows to just 20 feet! It is very shade tolerant, matched only by
Pacific Yew and
Pacific Silver Fir. It is long-lived; the oldest up to 1200 years old.
The leaves are in two distinct rows each side of the shoot: those which spread out horizontally are distinctly longer than those on the upper part of the twigs. Although it is evergreen, it does shed some leaves especially in very hot dry weather when they fall to the ground as a gentle rain, but never so many for the tree ever to be leafless. A brown peg is left where leaves have departed. They have one resin duct. Underneath the tree a carpet of brown needles can smother the grass in summer. The leaves, like most (all?) needles, are slightly poisonous (containing terpenoids) to other plants and act like gentle weed killers inhibiting the growth of grass and other plants which then grow less vigorously.
The main root system is only shallowly below ground with sometimes the upper parts visible. Coniferous trees can more easily be blown over than can deciduous trees with roots that delve deep underground. Trees with a shallow root system can suffer from lack of water in dry heat-waves much more than do trees with deeper roots which can find water in the depths.
The cambium below the bark is edible without any other preparation. Western Hemlock encourages some well known edible fungi such as Chanterelle. It is used as a tree for timber. The crushed leaves have little or no aromatic smell.