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ARBORETUM AND FRUTICETUM.

PART III.

suckers, are consequently killed in toto; while the oak, now sole possessorof the soil, starts up and grows vigorously. On the other hand, land whichhas been solely occupied by oaks previously to its cultivation, is invariably ofa superior quality to what is termed pine land; and is naturally a longerperiod under cultivation before it is turned out, by which means the rootsof the oaks are completely eradicated. The pine seeds, being winged, andthereby easily carried by the wind to a considerable distance, if the groundis free from the roots of other trees, are the first to establish themselves;and, being of a free and rapid growth, they take the lead of all other speciesof timber, and become the principal occupiers of the land: but when theroots of the oaks are not destroyed, they will take the lead, and resist thepine and other trees. All pine lands, which originally had no oaks, willinvariably produce pines again, whether they have been under cultivation fora long time or a short period.” ( Gard. Mag., vol. viii. p. 287.) In the northof Europe, including the Highlands of Scotland , a pine forest, unless it hasbeen cleared, and the soil brought under the plough, or laid down inpasture, continues such for ever; the seeds of the older trees coming up inthe open spaces, as thick as in the nurserymen’s seed-beds.

Accidents. With reference to the goodness and value of the timber, themost injurious accident that can befall a pine or fir tree is to have the deadstumps of the side branches left on, whether through neglect in artificialplantations, or from the trees not being sufficiently close together in naturalones. In such cases, the dead stump is buried under the living wood; and,when the tree is sawn up into boards, every point where these stumpsintersect the board forms a knot, which, if not glued in, generally drops out,leaving a hole through the board. The pine and fir tribe, from their resinousnature (resin being a powerful non-conductor), are said to be less liable tobe struck by lightning than broad-leaved trees; and hence they are con-sidered as particularly suitable for growing on mountains. (See Nuttall in Gar-dener’s Magazine, vol. xiii. p. 351.) As, when standing singly, their spirytops do not oppose so large a surface to the wind as those of round-headedtrees, and as their narrow leaves offer very little resistance, they are notso liable to be blown down by high winds as might be imagined from theircomparatively small roots; and they are still less so when associated toge-ther in dense masses of plantation or forest. As forests of the pine and firtribe are generally situated on hills or mountains, and for the most partin climates where they are subject to be covered with snow for severalmonths in the year, they are very liable to what may be called geologicaland meteorological accidents. In Switzerland , those movements of rocks,stones, and soil which take place in the mountainous districts, more or lessevery spring, and are called eboulemens, often destroy several acres of pm eforests at a time. In scattered forests, the snow falling on the trees ;individually is retained by their branches, and, when these are of greatlength, often weighs them down, and breaks them; while those move-ments of snow known by the name of avalanches are sometimes as injuri-ous as the eboulemens. We have seldom been more gratified with winterscenery, than when passing through a spruce fir forest in Sweden . W ehave seen trees of all ages grouped and distributed in innumerable ways; ,here weighed down with snow, and there boldly shooting through it theirvivid green pyramidal heads. When a sudden thaw takes place in spring, the ;snow and the branches seem all in motion; some branches, being relieved jfrom their load of snow, are rising up in consequence of their elasticity! jand others, from the snow falling on them from branches still higher up the itree, are bending, and perhaps breaking, under the additional weight. In the ,pine and fir forests of Europe , a number of branches, and also of entire trees,are damaged in this way every year; but this is nothing to the havock whicdtakes place in America , during what is called an “ ice storm.” In the Magaa* eof Natural History (vol . vi. p. 100.), a very striking description of one ethese storms at Philipsburg, near the Alleghany Mountains , is given by R.

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