CHAP. CXIII.

coni'fekjs. ^bie'tinae.

2139

a tremendous roaring in the woods, resembling the incessant rolling ofthunder; while, at the same time, the atmosphere became thickly darkenedwith smoke. They had scarcely time to ascertain the cause of this pheno-menon, before all the surrounding woods appeared in one vast blaze, theflames ascending more than 100 feet above the top of the loftiest tree ; andthe fire, like a gulf in flames, rolling forward with inconceivable celerity. Inless than an hour Douglastown and Newcastle were enveloped in one vastblaze, and many of the wretched inhabitants, unable to escape, perished inthe midst of this terrible fire.” (Sketches of the Mar. Col. of British America .)

In some parts of Sweden , also, the pines and firs are purposely burnt, toclear the fields for agricultural purposes; but there are also extensiveaccidental fires. Dr. Clarke, describing his journey from Stockholm northward, says : “ As we proceeded to Hamrange, we passed throughnoble avenues of trees, and saw some fine lakes on either side of the road.Some of the forests had been burned, by which the land was cleared forcultivation. The burning of a forest is a very common event in this coun-try; but it is most frequent towards the north of the Gulf of Bothnia .Sometimes a considerable part of the horizon glares with a fiery' redness,owing to the conflagration of a whole district, which, for many leagues inextent, has been rendered a prey to the devouring flames.” In Lapland ,beyond Tornea , he adds, “ some forests were on fire near the river, andhad been burning for a considerable time.” Mr. Tipping informed us thatthese fires were owing to the carelessness of the Laplanders and boatmenon the rivers, who, using the .Boletus (Polyporus) igniarius (Germantinder) for kindling their tobacco-pipes (see p. 1834.), suffer it to fall in anignited state among the dry leaves and moss. They also leave large firesburning in the midst of the woods, which they have kindled to drive awaythe mosquitoes from their cattle and from themselves; therefore, the con-flagration of a forest, however extensively the flames may rage, is easilyexplained. Yet Linnaeus , with all his knowledge of the country, and customsof the inhabitants, attributed the burning of forests in the north of Sweden to the effects of lightning. During these tremendous fires, the bears, wolves,and foxes, are driven from their retreats, and make terrible depredationsamong the cattle.” ( Travels, fyc.)

Diseases. The pine and fir tribe are subject to some diseases, and moreparticularly to the flow of resin, in consequence of being wounded by pruningwhen the sap is in active motion in spring. They are also affected by can-kerous excrescences; and the wood is liable to become shaky; an evilwhich, of course, is not observed till the tree is cut down, and sawn intoboards, when the annual layers are found to separate from each other.The larch is subject to a very peculiar disease, called pumping, which rotsout the heart wood, and which we shall describe when speaking of that tree.

Insects. Mr. Westwood, to whom we are indebted for this article, ob-serves, that the attacks of the insect tribes upon the genus -/hnus are not,in this country, so prejudicial as in Sweden and some parts of Germany ;where, owing to their very great extent, the pine forests are of such vastimportance. Hence it is that in these countries the investigation of thehabits of the different species of insects which attack the pine and fir tribehas been pursued with much more care than among us. We shall availourselves in this article of the most recent labours both of Continental andEnglish authors, adding thereto some original matter, which we have notfound noticed in their works.

The insects which attack the different species of Pinus may be divided intotwo classes; viz., internal feeders, and external feeders. The former maya i= alr ‘ he separated into those which burrow into the wood, and those whichMerely reside beneath the bark: not, indeed, that the latter are less injuriousnan the former; because, as in the elm-destroying Scolytus, the presence® great numbers of subcortical species causes the death of a tree aspeedily as those which strip it of its leaves, or burrow into its solid sub-

ice, and, indeed, often more speedily.