Detection of Disease. 



endeavour to deal directly with it, and show 

 (i) how its presence may be detected; (2) 

 the probable causes ; (3) the cure; and (4) the 

 prevention; and, lastly, how far the yield of our 

 woodlands may be increased by the introduc- 

 tion of useful conifers hitherto grown for 

 ornament only. 



Disease or impaired health may be detected 

 in various ways — ;by that which is apparent to 

 the passer by, and by that which is apparent 

 only to the trained observer. In the former 

 case we have premature defoliation, the 

 presence of lichen, the dead upper branches, 

 the holes in the stem, the decayed base, and 

 the visible general enfeeblement. In the 

 latter, we have the short and feeble shoots, 

 the undue presence of seed on young trees, 

 the bark-bound condition, the cancerous con- 

 dition, the presence of insect and fungoid 

 attacks, and the early or late development of 

 leaf. It will be seen that the manifestations 

 are both numerous and apparent, and, as I 

 have stated, the gist of the whole matter lies 

 in the ability to detect these when in an 

 incipient state. 



