The European larch was known in England fully one hundred years before it arrived in Scotland, having been introduced into Southern Britain early in the seventeenth century. But it was long before this tree was grown except for ornament and by those curious in exotics; it was John Evelyn who first drew attention to the value of its timber, upon which he reported very favourably after seeing it in Continental forests. Writing in 1678, he refers to one growing near Chelmsford, "arriv'd to a flourishing and ample tree, [which] does sufficiently reproach our negligence and want of industry"—for not planting more larches.

The introduction into Scotland of the larch, the most valuable of all European conifers, was delayed a full century after the tree had become known to English planters. When it did come, it opened a new era in the forestry of that country; and, if credit may be given to local traditions, its coming was not devoid of romance.

Among the other resources of the northern realm, which had been sorely exhausted during three centuries of war with England, Scottish woodland, once so rich and extensive, had well-nigh disappeared, and so bare was the country that when Dr. Johnson made his tour in 1773 he declared that in the whole of it he only saw three trees big enough to hang a man upon.[19] Nevertheless, after the Legislative Union in 1707, landowners very generally set about planting on their estates, none of them more diligently than James, second Duke of Atholl, who received from a neighbour returning from the Continent the present of a few seedling trees which he had brought in his portmanteau from the Tyrol. It is said that these were given to the gardener, who tried to grow them in a greenhouse. Having languished under such unsuitable conditions, the plants were thrown out upon the rubbish heap, where two of them, reviving in the free Highland air, took root and grew vigorously.

The date of this incident is variously given between the years 1727 and 1738; anyhow, there the pair of "Mother Larches" stood, close to the west end of Dunkeld Cathedral, until 1909, when the larger of them was destroyed by lightning, after attaining the age of 170 years or thereby. It measured 102 feet high, with a girth of 15 feet 1 inch at 5 feet from the ground, and contained about 530 cubic feet of splendid timber.

The Duke of Atholl was so well pleased with the growth and appearance of these two trees, and of three others of the same age, which, I believe, are still standing at Blair, that before his death in 1764 he had wholly altered the appearance of the landscape by planting many square miles of hillside with larch. His example was followed by other landowners, so that during the nineteenth century larch was planted in greater quantity than any other tree, except perhaps Scots pine, for it was found that, owing to the durable character of the wood even in trees from ten to twenty years old, the thinnings of a larch plantation were serviceable and readily saleable.

Unfortunately, it became the practice to plant larch and Norway spruce in mixture. No more mischievous combination could have been devised, owing to a peculiarity in the life history of the spruce-gall aphis (Chermes abietis), a plant louse which bores into the buds of young spruce and lays eggs therein, causing the tree to throw out a cone-like gall from the site of the puncture. This gall is the nursery whence issues a swarm of sexual and sexless aphides. The sexless form has wings, and, alighting on a larch, speedily lays numerous eggs, which in turn are hatched into minute sexless lice, each with a coat of white down, easily detected as snowy dots on the foliage. In a few weeks these creatures acquire wings, and, despite their sexlessness, lay fertile eggs, successive swarms being produced till the fall of the leaf. Feeding by suction of the juices in the leaves, these creatures seriously, often fatally, reduce the vitality of the tree, the foliage appearing as if blighted by frost.

It must be admitted that this diagnosis of the life-history of the spruce and larch louse is to some extent tentative. It is true that no instance is recorded of the male Chermes being found on the larch, and it is also true that, as stated by Elwes, larches are often infested with Chermes where there are no spruces near.[20] But it is well known that many, if not all, of the AphidÆ multiply by parthenogenesis (that is, without the intervention of the male), and although it has not yet been ascertained that this can be continued for more than four years,[21] that is a period quite long enough to allow of the swarms inflicting deadly injury to any tree not in the most robust health.

Now, whereas larch and spruce may often be found growing together in natural woods on the continent of Europe, it may be asked why the result of planting them together in British woods should be attended with such evil consequences. The explanation is to be found in the climatic conditions to which the larch is exposed in these islands. Naturally a mountain tree, in regions where a high summer temperature, long and strong sunshine, with little rainfall, but with much subterranean moisture from melting snow, promote vigorous growth, to be followed by total rest during severe winter weather, the larch meets in Britain with the reverse of these conditions—namely, a cool, cloudy, generally wet, summer, and an open and still wetter winter. The wonder is that the tree can adapt itself to the change as well as it does; there can be no doubt that its constitution does not remain so well able to resist attack by insect or fungoid parasite. Nature, which is ever as solicitous to provide for the perpetuation of what we consider ignoble vermin as she is for that of more admirable forms of life, has adapted the spruce-gall for a dual existence upon two species of tree growing in company; but she has also endowed these trees with a constitution vigorous enough not to suffer materially from the presence of the parasite. When that constitution becomes impaired by unnatural conditions of climate and environment, the parasite gets the upper hand, just as lice multiply upon a diseased bird or mammal. In the case of the larch, the mischief does not end with the aphides.

Another enemy lies in wait for the tree that has been weakened by loss of its sap. A minute fungus (Dasicypha calycina), gaining access by its spores through any lesion of the bark, causes that incurable ill known as larch canker, which has now become so generally spread through British woodlands as to cause many landowners to give up planting larch at all. In this case, also, we have a parasite which may be found on larches in their native forests, but which the inherent vigour of the trees keeps in check. That this is the true and only reason for the excessive prevalence of larch canker in this country, causing incalculable pecuniary loss to many owners of woodland, is shown by the behaviour of the Japanese larch (Larix leptolepis). The fungus may easily be found upon this species; but so great is the vigour of the young trees that the fungus exists, and no more. The tree repels the inroads of mycelium into its tissues affording the invader foothold merely as a harmless guest.

Serious doubts are entertained as to whether the Japanese larch will prove as valuable a tree commercially as the European species; it has not been grown long enough in Britain to prove its quality as a timber producer. But the extraordinary rapidity and vigour of its growth in early years, its beauty and the readiness with which it takes hold when planted out, have induced many people to discard European larch in favour of this Asiatic species. Travellers in Japan report that the larches of that country never attain the bulk and stature of European larches; but it does not follow from this that they may not do so in this country. The holm-oak, more commonly known as ilex, is a native of the hot and dry Mediterranean region, yet what is probably the tallest specimen in the world is growing in the moist atmosphere of County Wicklow. So with the horse chestnut, only to be found wild in a few spots in Macedonia and Asia Minor, lands which can show none to equal the noble trees of this species at Bushey and elsewhere throughout the British Isles.

Meanwhile, the lesson of our experience is that we must still treat the European larch as a foreigner of great distinction. Let it never be exposed to contact with the Norway spruce, a useful tree in its way, but, commercially, not half the value of larch. Let it not be planted as a pure crop, but let it be mixed with other trees, as it is usually found in a wild state. There is no better companion for it than the beech, none, indeed, equal to that beneficent tree, owing to the manner in which it screens the soil from evaporation and radiation, and refreshes it with an abundant annual leaf fall. Finally, let the utmost care be bestowed upon the critical operation of planting; see that in removal from the nursery the roots are not suffered to get dry, as they often become when sent to a distance by rail; and let these roots be fairly spread in the pit dug for them, instead of being rammed in a bunch into a mere notch in the ground, as is too often done. It is worth much effort to retain such a desirable denizen of our woodlands in health and vigour.

Attention has been drawn within the last few years to the Western Larch (L. occidentalis) of North America, a tree which Douglas found in British Columbia in 1826, and mistook for Larix europÆa. It has now, however, been recognised as a distinct species, the mightiest of the genus, reaching a height of 180, perhaps 200 feet.[22] In habit and outline it is very different from the European larch, still more so from the Japanese species, for the side branches, though horizontal, are short, which gives the tree a fine columnar habit. Owing to the great height of the trees in Montana and British Columbia, and to the cones opening and scattering the seed as soon as ripe, it is difficult to collect a supply of seed, which can only be done from trees in September. Dr. Henry visited Montana in the autumn of 1906 on purpose to obtain a supply. Unluckily, very few cones were formed that year; but a good supply was obtained in 1907, whereof I was given some. It germinated freely; the seedlings grew as rampantly as those of Japanese larch, forming beautifully rooted plants; I cleared the hardwood off three acres of good land, and planted it with 12,000 western larch, fine rooted plants, in the spring of 1910. The result has been discouraging; about 50 per cent. died outright, and by the end of 1914 the remainder have made poor growth. On the other hand, a dozen seedlings which Mr. Elwes sent me, raised from seed in 1904, and planted on moist but well-drained bottom land, have grown fast and well, being now 14 to 18 feet high. Evidently this tree, like the Sitka spruce, requires moist deep land; the other place, though far from being poor, was not wet enough for it.

There are three specimens of the western larch at Kew, one being 34 years planted and about 35 feet high; but the soil of Kew is too dry to nourish without much coddling a tree whereof all reports go to show that it demands so much moisture at its roots as would be fatal to the European and Japanese species. Sheltered valleys on the western side of Great Britain seem to be the likeliest environment for the development of this most valuable timber tree, and probably nearly all parts of Ireland.