304 ENGLISH ESTATE FORESTRY 



isolated larches that can be found, and the fructifications are 

 invariably present on them. This fact is sufficient to prove 

 that the mere existence of the fungus does not necessarily 

 lead to diseased trees — using the term " diseased " in its 

 practical sense. 



Heakt-Eot in Laech. 



Although the true larch disease has received its full 

 share of attention of late years, and is considered by many 

 to be the most destructive pest that we have in England, it 

 is probable that a careful examination of the various planta- 

 tions throughout the country would reveal the fact that 

 " heart-rot " is equally, if not more, destructive to the tree, 

 and more detrimental to the value of the timber than Peziza 

 Wilkommi. That this has not met with such attention as 

 the latter in late years is probably due to its obscure nature, 

 and to the fact that it is only when the trees are cut down 

 that it can be diagnosed with certainty. But fifty years ago 

 it was considered to be the only disease that affected larch 

 to any serious extent, and, when old foresters spoke of the 

 larch disease, heart-rot was always referred to. M'Intosh, 

 in his book already cited, devoted a great deal of time to its 

 examination, and collected all the existing literature and 

 opinions available on the subject, although no very definite 

 conclusions were arrived at after all. Hartig refers to it 

 under the name of " root-rot," but more in reference to trees 

 generally than larch in particular. He considers it due to 

 stagnation of the air in wet or compact soils, and often to 

 the cultivation of the ground previous to planting, and its 

 subsequent settling down after the roots have spread freely 

 into it. But, whatever the authority we consult, all agree 

 in believing it to be the direct result of unsuitable soil, 

 although the belief that wet soil is the cause has as many 

 adherents as that which attributes it to dry. 



The average heart-rot in larch, however, must not be 

 confounded with that caused by Trametes radiciperda, although 

 the latter produces the same effect in its early stages. But 

 attacks by Trametes radiciperda invariably kill the tree in a 

 year or two, while the progress of heart-rot may continue 



