LARCH DISEASE INQUIRY. 215 



Sylvicultural Treatment. 



16. Under similar conditions as to elevation, aspect, soil, etc., 



have you observed whether disease is more prevalent — 

 {a) In pure or in mixed crops ? {b) In dense pure crops 

 or in open ones ? {c) In planted or in self- or artificially- 

 sown crops ? {d) In plantations formed with plants raised 

 from home-grown seed, or in those formed with plants 

 raised from foreign-grown seed ? {e) In pure crops on 

 shallow soils or in those on deep soils ? 



17. What particular mixture (or mixtures) of other species with 



the larch seems to be most effective in warding off 

 disease ? 



18. What is your experience of the disease in a mixture of larch 



and spruce ? 



19. Have you ever observed crops to be badly attacked by 



Aphis, although no spruce existed in the locality ? 



20. Have you observed whefrier there has been less liability to 



disease when in a mixture the larch plants have been 

 planted in advance of the other species ? 



21. Have you observed whether the tree was specially suscept- 



ible to disease when planted on land which had previously 

 been under agricultural crops ? 



22. Under similar conditions as to age, density, soil, etc , is 



disease more prevalent in pure crops on certain aspects 

 than on others, and, if so, on which ? 



23. Have you observed whether the growing of successive crops 



of larch on the same ground has any effect in inducing 

 the disease ? 



Miscellaneous. 



24. Have you observed whether, on soils on which the trees 



seemed particularly susceptible to the disease, there 

 was also a tendency for them to become affected by 

 "heart-rot".? 



25. Have you observed whether wounds made on the stems of 



healthy trees during the growing season heal by occlusion 

 as readily as when made in the resting season ? 



26. Have you ever observed wounds produced on the stem to 



remain unhealed for several years, and to continue to 



