LARCH, a name applied to a small group of coniferous trees of the class Gymnosperms. The members of the genus Larix are distinguished from the firs by their deciduous leaves, scattered singly on the young shoots of the season, but on all older branch lets growing in whorl-like tufts, each surrounding the extremity of a rudimentary or abortive branch; they differ from cedars (Cedrus) not only in the deciduous leaves, but in the cones, the scales of which are thinner and persistent. There are about io species, natives of Europe, or the northern plains and mountain ranges of Asia and North America, though one (Larix Griffithii) occurs only on the Himalayas.
The common European larch (L. europaea) is a stately tree with tall erect trunk, gradually tapering from root to summit, and horizontal branches springing at irregular intervals from the stem, and in old trees often becoming more or less drooping, but rising again towards the extremities ; the branchlets or side shoots, very slender and pendulous, are thickly studded with the spurs, each bearing a fascicle of 3o or more narrow linear leaves, of a peculiar bright light green when they first appear in the spring, but becom ing of a deeper hue when mature. The erect, oblong cones, which remain long on the branches, are about 1 in. long, with reddish brown scales. The tree flowers in April or May, and the winged seeds are shed the following autumn. In the common European varieties the bark is reddish-grey, and rather rough and scarred in old trees. The trunk attains a height of from 8o to 14o ft., with a diameter of from 3 to 5 ft. near the ground, but in close woods is comparatively slender.
The larch abounds on the Alps of Switzerland, on which it flourishes at an elevation of 5,000 ft., and also on those of Tirol and Savoy, on the Carpathians, and in most of the hill regions of central Europe. It grows extremely rapidly, the stem attaining a large size in from 6o to 8o years, while the tree yields good use ful timber at 4o or so years. The wood of large trees is compact in texture, in the best varieties of a deep reddish colour varying to brownish-yellow. When well prepared for use, larch is one of the most durable of coniferous woods. Its strength and toughness render it valuable for naval purposes; its freedom from any tendency to split adapts it for clinker-built boats. It is much em ployed for house-building in Switzerland, the log-houses there deriving their fine brown tint from the hardened resin that slowly exudes from the wood after long exposure to the summer sun. It answers well for fence-posts and river piles; many of the foundations of Venice rest upon larch.
In the trunk of the larch, where the sun is powerful in summer, a fine clear turpentine exists in great abundance; in Savoy and the south of Switzerland, it is collected for sale, though not in such quantity as formerly, when, being taken to Venice for ship ment, it was known in commerce as "Venice turpentine." Real
larch turpentine is a thick tenacious fluid, of a deep yellow colour, and nearly transparent ; it does not harden by time ; it contains 15% of the essential oil of turpentine, also resin.
The larch does not seem to have been much grown in England till early in the 18th century. It grows as rapidly and attains as large a size in British habitats suited to it as in the Alps, and often produces equally good timber. The European larch has long been planted in the eastern United States for ornament and to a limited extent for timber. The Japanese larch (L. Kaempferi) is widely planted. This Oriental species attains a height of 90 ft.; it has horizontal branches, soft bluish-green leaves marked with two white bands beneath, and ovoid cones 1 in. to II in. long.
The golden larch (Pseudolarix amabilis) is a beautiful ornamental I tree planted for its light-green feathery foliage, which turns yellow in autumn. It is native to eastern China, where it grows to a height of 130 ft., and differs from the true larches in having larger cones with deciduous scales, longer and broader leaves, and pendulous clusters of staminate flowers.
In North America there are three native species of larch. Of these the most widely distributed is the American larch (L. laricina), commonly called tamarack, known also as hackmatack and to the French Canadians as epinette rouge. It attains a height of 5o ft. to 6o ft. and a trunk diameter of I 4 ft., and re sembles the European larch, but has much smaller cones. The tamarack grows from Newfoundland and Labrador north-west ward to Mackenzie, where it extends in dwarf forms to the Arctic ocean, and also in western Alaska. It occurs sparingly southward to West Virginia, northern Indiana, Minnesota and the eastern base of the Rocky Mo•intains in Alberta. At the south it is found only in deep cold swamps, but at the north it often grows on well drained uplands. The tamarack reaches its greatest size north of Lake Winnipeg and is the largest tree in Labrador. The hard, strong, durable wood is put to numerous uses, as for railway-ties, telegraph-poles and fence-posts.
The largest North American species is the western larch (L. occidentalis) ; this Lometimes grows 25o ft. high, with a tapering, naked trunk, 6 ft. to 8 ft. in diameter, terminating in a short nar row pyramidal head of fine branches. It occurs, usually at from 2,000 ft. to 7,00o ft. altitude, from southern British Columbia to northern Oregon and eastward to Montana. The heavy, close grained, very durable, light red wood is suitable for many uses. In 1925 the total lumber cut of western larch was 286,459,000 bd.ft., valued at the mill at $5,127,876. The alpine larch (L. Lyallii), a tree, usually 4o ft. to so ft. high, is restricted to a nar row belt near the timber line on high mountains from southern British Columbia and Alberta to Oregon and Montana.