288 ENGLISH ESTATE FORESTRY 



dying trees alone merely hasten natural decay, and it is only 

 when exceptional circumstances occur that they attack and 

 possibly kill trees which, otherwise, would carry on a more or 

 less sickly existence. Such circumstances occur when trees 

 of a large size, or those scantily furnished with fibrous roots, 

 are transplanted. The check in their regular growth 

 experienced by such trees, and their inability to meet the 

 extra call made upon their resources, in all cases throws 

 them into a temporary state of debility, and in many cases 

 permanently cripples them. This weakened condition is 

 often taken advantage of by insects which, under normal 

 circumstances, would be perfectly harmless. Amongst such 

 beetles may be named the elm-bark beetle, the ash-bark 

 beetles (H. fraxini and crenatus), Tomicus bidens, etc. Of 

 these, T. Helens appears to us to be the most troublesome. 

 Newly planted coniferous trees are frequently attacked by 

 this beetle, and often destroyed outright. Such trees are, no 

 doubt, weakened by transplanting, but not to an extent 

 which would render recovery impossible under normal 

 conditions. But when attacked by T. Widens in May and 

 June, the burrowing of the beetles has a most injurious 

 effect upon the trees, and it is seldom that an attacked tree 

 recovers. It is one of the moat impartial bark beetles in 

 the country ; for, although its most frequent host plant is 

 Scots fir and pines generally, it may be found on larch, 

 spruce, deodar, cupressus, and conifers of all kinds. 



FUNGI. 



In common with the vegetable kingdom generally, trees 

 have their fair share of enemies amongst those fungi which 

 are known under the name of " parasites." Whether genuine 

 saprophytes can be termed injurious to living trees or not, 

 is a difficult question to answer off-hand ; but there are 

 certainly one or two of them which bear a very doubtful 

 character. But probably the worst foes the forester has to 

 deal with are those which combine the properties of both, 

 and are able to exist as a parasite to-day and a saprophyte 

 to-morrow. Such fungi are known as " facultative," and it 



