Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/329

 LARCH 311 does not seem to have been much grown in England till early in the last century. In Scotland the date of its introduction is a disputed point, but it seems to have been planted at Dunkeld by the duke of Athole in 1727, and about thirteen or fourteen years later considerable plantations were made at that place, the commencement of one of the largest planting experiments on record ; it is estimated that 14 million larches were planted on the Athole estates between that date and 1826. The cultivation of the tree rapidly spread, and the larch has long become a conspicuous feature of the scenery in many parts of Scot land. It grows as rapidly and attains as large a size in British habitats suited to it as in its home on the Alps, and often produces equally good timber, but has sometimes been planted under circumstances little adapted to its successful growth. The larch of Europe is essentially a mountain tree, and requires, not only free air above, but a certain moderate amount of moisture in the soil beneath, with, at tho same time, perfect drainage, to bring the timber to perfection, conditions often occurring on the mountain slope and rocky glen that form its natural habitats, but not always so readily provided in artificial culture. Complete freedom from stagnant water in the ground, and abundant room for the spread of its branches to light and air, are the most necessary requirements for the successful growth of larch, the contrary conditions being the most frequent causes of failure in the cultivation of this valuable tree. Where these important needs are com plied with, it will flourish in a great variety of soils, stiff clays, wet or mossy peat, and moist alluvium being the chief exceptions ; in its native localities it seems partial to the debris of primitive and metamorphic rocks, but is occasionally found growing luxuriantly on calcareous sub soils ; in Switzerland it attains the largest size, and forms the best timber, on the northern declivities of the mountains ; but in Scotland a southern aspect appears most favourable. The best variety for culture in Britain is that with red female flowers ; the light-flowered kinds are said to pro duce inferior wood, and the Siberian larch does not grow in Scotland nearly as fast as the Alpine tree. The larch is raised from seed in immense numbers in British nurseries ; that obtained from Germany is preferred, being more perfectly ripened than the cones of home growth usually are. The seeds are sown in April, on rich ground, which should not be too highly manured ; the young larches are planted out when two years old, or sometimes transferred to a nursery bed to attain a larger size ; but, like all conifers, they succeed best when planted young ; on the mountains, the seedlings are usually put into a mere slit made in the ground by a spade with a triangular blade, the place being first cleared of any heath, bracken, or tall herbage that might smother the young tree ; the plants should be from 3 to 4 feet apart, or even more, according to the growth intended before thinning, which should be commenced as soon as the boughs begin to overspread much ; little o r no pruning is needed beyond the careful removal of dead branches. The larch is said not to succeed on arable land, especially where corn has been grown, but recent experience does not seem to support this prejudice ; that against the previous occupation of the ground by Scotch fir or Norway spruce is probably better founded, and, where timber is the object, it should not be planted with other conifers. On the Grampians and neighbouring hills the larch will flourish at a greater elevation than the pine, and will grow up to an altitude of 1700 or even 1800 feet ; but it attains its full size on lower slopes. In very dry and bleak localities, the Scotch fir will probably be more successful up to 900 feet above the sea, the limit of the luxuriant growth of that hardy conifer in Britain ; and in moist valleys or on imperfectly drained acclivities Norway spruce is more suitable. The growth of the larch while young is exceedingly rapid ; in the south of England it will often attain a height of 25 feet in the first ten years, while in favourable localities it will grow upwards of 80 feet in half a century or less ; one at Duukeld felled sixty years after planting was 110 feet high; but usually the tree does not increase so rapidly after the first thirty or forty years. Larches now exist in Scotland that rival in size the most gigantic specimens standing in their native woods, a tree at Dalwick, Peeblesshire (said to have been planted in 1725), is 5 feet in diameter; one at Glenarbuck, near the Clyde, is above 140 feet high, with a circumference of 13 feet. The annual increase in girth is often consider able even in large trees ; the fine larch near the abbey of Dunkeld figured by Strutt in his Sylva Britannica increased 2^- feet between 1796 and 1825, its measurement at the latter date being 13 feet, with a height of 97-| feet. In the south of England, the larch is much planted for the supply of hop-poles, and is considered one of the best woods for that purpose, the stems being straight and easily trimmed into poles, while they are extremely durable,, though in parts of Kent and Sussex those formed of Spanish chestnut are regarded as still more lasting. In plantations made with this object, the seedlings are placed very close (from 1| to 2 feet apart), and either cut down all at once, when the required height is attained, or thinned out, leaving the remainder to gain a greater length ; the land is always well trenched before planting. The best season for larch planting, whether for poles or timber, is the month of November ; the operation is sometimes performed in the spring, but the practice cannot be commended, as the sap flows early, and, if a dry period follows, the growth is sure to be checked. The thinnings of the larch woods in the Highlands are in demand for railway sleepers, scaffold poles, and mining timber, and are applied to a variety of agricultural purposes. The tree generally succeeds on the Welsh hills, and might with advantage be planted on many of the drier mountains of Ireland, now mere barren moor land or poor unremunerative pasture. The European larch has long been introduced into the United States, where, in suitable localities, it flourishes as luxuriantly as in Britain. Of late years some small plan tations have been made in America with an economic view, the tree growing much faster, and producing good timber at an earlier age, than the native hackmatack, while the wood is less ponderous, and therefore more generally applicable. The larch in Britain is occasionally subject to destructive casual ties. The young seedlings are sometimes nibbled by the hare and rabbit ; and on parts of the Highland hills both bark and shoots are eaten in the winter by the roe-deer, which is a great enemy to young plantations ; larch woods should always be fenced in to keep out the hill-cattle, which will browse upon the shoots in spring. The &quot;woolly aphis,&quot; &quot;American blight,&quot; or &quot;larch blight&quot; (Eriosoma laricis) often attacks the trees in close valleys, but rarely spreads much unless other unhealthy conditions are present. A far more formidable enemy is the disease known as the &quot;heart-rot&quot; ; it occurs in all the more advanced stages of growth, occasionally attacking young larches only ten years old or less, but is more com mon at a later period, when the trees have acquired a considerable size, sometimes spreading in a short time through a whole planta tion. The trees for a considerable period show little sign of un- healthiness, but eventually the lower part of the stem near the root begins to swell somewhat, and the whole tree gradually goes off as the disease advances ; when cut down, the trunk is found to be decayed at the centre, the &quot;rot&quot; usually commencing near the ground and gradually extending upwards. Trees of good size are thus rendered nearly worthless, often showing little sign of unhealthiness till felled. Great difference of opinion exists among foresters as to the cause of this destructive malady ; the manner in which it spreads would seem to indicate a fungoid origin, and the previous growth of pine on the ground is one of the most usual explanations offered. That some fungoid mycelium may be the remote cause of the disease seems not improbable ; but there is little doubt that anv circumstance that tends to weaken the tree acts as