EEPORT ON LARCH FORESTS. 381 



of larch has continued, and uniformly increased since its first 

 introduction ; the markets have continued well supplied, and the 

 quantity has gradually increased. The trade in larch is an im- 

 portant one ; numberless are the purposes to which it is applied, 

 and endless the demand. The disposer of larch finds a good and 

 ready market, and the buyer can always be supplied at moderate 

 rates. Judging from present appearances, the larch forests through- 

 out Great Britain, taken as a whole, will continue to yield abund- 

 ance of sound and healthy wood for many years. Instead of larch 

 wood being exhausted, or even scarce, the prospects are those of 

 increase and abundance. From all the information we can gather, 

 it appears that the failure of larch seventy years ago was due to 

 the same causes as we now find in operation, — wet clay soils ; 

 low situations ; rich black loam ; loose light sand ; hard moor, or 

 cultivated and manured soils, having been planted which should 

 never have been. 



The Duke of Athole, speaking of the larch blight which oc- 

 curred in 1725, says — " Trees thirty feet in height, and in high 

 situations, escaped this affection, where the wind could shake 

 them. This blight destroyed the flower of the larch, and pre- 

 vented the formation of the seed, and consequently the propa- 

 gation of the plant. The first indication of the blight was a 

 substance upon the leaves resembling small balls, of a fine white 

 matter like cotton. These balls or nidi enclosed small insects, a 

 species of aphis, the two sexes of a very different appearance. 

 They appear to live upon the juice exuding from the bark of the 

 tree, and not upon the leaves, and they probably prevented the 

 sap from ascending, at least no fresh shoots were thrown out 

 by the tree that season. Many trees were much injured by this 

 disease, and for a long time afterwards they presented a remark- 

 able appearance — that of being completely covered over with 

 lichens. On cutting the wood, the fogged part was no more 

 injured in quality than the wood of the healthiest trees, though 

 the lichens had adhered to them for fifteen years. The effect of 

 this blight then was only superficial." The writer has uniformly 

 regarded the Coccus laricis of itself a harmless thing, but looks 

 upon it as an indication of confinement, low situation, richness 

 of soil, and general sluggish growth. Healthy growing trees are 

 often partially infested with Coccus laricis, and yet attain large 

 dimensions, and are quite sound in the wood. The probability is, 

 that the Duke of Athole describes two or more diseases as one, viz., 

 Coccus laricis, and the effects of spring frosts or wet soils. The 

 lichens upon the trees were doubtless due to a wet surface, which 

 luxuriant herbage often induces or promotes. On examining the 

 forests, the writer was very much surprised at the immense 

 quantity of lichens upon the trees at high altitudes, and yet 

 the trees quite healthv. The rocks, stones, palings, and stone 



2 c 



