THE FAILURES OF THE LARCH. 61 



V. The Failures of the Larch* By William Gorrie, Rait 

 Lodge, Trinity. 



The failures of the larch, whether considered economically or 

 scientifically, is the most important subject that now forces itself 

 upon the attention of both forest-owners and foresters ; for not 

 only have failures of the larch involved vast pecuniary losses in 

 many districts of Britain, but the diversity in appearance which 

 the plague-stricken trees present under apparently similar, as well 

 as very different influences, has led to the adoption and dissemina- 

 tion of many theories regarding their causes and prevention, most 

 of which have not stood the tests of minute inquiry and careful 

 experiment. Under such circumstances, I cannot expect that the 

 opinions I now promulgate will entirely coincide with those of 

 many members, so that ample room will be afforded for eliciting 

 information on the important subject before us. And in regard 

 to the opinions, or rather convictions, that I express, I may state 

 that they are the results of long-continued as well as widely- 

 extended practical observations. 



The principal causes of larch failures I shall notice under three 

 heads : — 



I. Heart-i'ot, dry-rot, or pumping. 



II. Surface-rot, cancer, cankering, or blistering, and top-rot. 



III. The larch bug, or blight {Adelgis laricis of Vallot, and 

 Coccus laricis of previous authors), which is also frequently desig- 

 nated the Aphis disease. 



I. Heart-rot, dry-rot, or pumping. — The outward indica- 

 tions of fully-established heart-rot are — the tree becoming per- 

 ceptibly thickened under about two feet from its base ; the 

 bark of both stem and branches assuming an unhealthy, dried, 

 and more or less moss or lichen covered appearance — the 

 length and abundance of such covering being in proportion to 

 the atmospheric dampness of the situation ; and the stunted, de- 

 creasing growth of the annual shoots and foliage, till the tree 

 becomes partly and ultimately wholly dead. When cut down, the 

 internal appearances are — first, unhealthy, darkish discoloration of 

 the portions of the red or heart-wood, spreading and changing from 



* Read by the author at the Twenty-Second Annual Meeting in opening a 

 discussion on the Failures of the Larch. — Ed. 



