l8o TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Sometimes climatic reasons bring about an epidemic, as for 

 instance when trees are grown in a humid, still hollow where the 

 wind does not reach them. Unsuitable soil, as for instance a wet 

 heavy alluvium or even a poor dry soil, may render the trees 

 feeble and unhealthy so that they cannot throw off the effects 

 of the disease, and eventually they succumb. 



Cieslar (i), one of the very best continental authorities, 

 considers that any one of these conditions may produce a 

 dangerous epidemic of Peziza. 



But so far as ir-cotland is concerned, there is no question 

 but that first-rate larch can be grown in our climate in suitable 

 localities. Magnificent larches have, in fact, been grown, and 

 in many different districts. 



So far as one can gather from observation, those plantations 

 which are over fifty years old hardly seem to have been seriously 

 attacked by the disease. The damage is most visible in planta- 

 tions of from ten to fifty years of age. There has been a great 

 improvement during the last ten years, but this may be due to 

 the undoubted development in forestry that is now obvious 

 everywhere in Scotland. 



As a matter of personal observation, much of the injury seems 

 to be due to careless silviculture. I have myself seen larches 

 planted in a perfectly flat peat moss with a subsoil of stiff 

 estuarine clay and in a sheltered place. They happened, in this 

 case, to be attacked by insects rather than by Peziza, but it was 

 obvious enough that whoever it was that planted larch in such a 

 situation was guilty of arboricide. 



Mr S. J. Gammell of Drumtochty also informs me that in 

 humid, windless places. Aphis and not Peziza is usually the 

 executioner selected. 



I know also of cases where, on the same property and within 

 half a mile of one another, one plantation on a steep hillside 

 was healthy and vigorous, hardly showing a trace of disease, 

 whilst others on the flat alluvium of the river valley were rapidly 

 dying and obviously doomed to destruction. 



But although the question is confused by these considerations, 

 it is certain that very fine larch have been and are still, in a few 

 places, being grown in Scotland. Therefore our climate is not 

 solely to blame for the bad state of so many plantations to-day. 



Are we using the same variety of the larch that was planted 

 seventy and more years ago ? 



