Is root disease more common now than in the past? In general, root diseases were 

 probably less frequent and in smaller centers in the past than currently. Why? 



• Harvesting root-diseased trees left infected roots in the ground and 

 increased chances for contact with roots of healthy trees. 



• Regeneration of root-disease-susceptible species has 

 been encouraged. 



• Compaction on sensitive soils has reduced vigor of residual trees, 

 leaving them more vulnerable to armillaria root disease. 



• Fire suppression has favored root-disease-susceptible species. 



• Injury of roots and lower stems during harvest operations can attract 

 insects that spread black stain root disease in susceptible hosts. 



• Creation of more stumps has resulted in more habitat for some root 

 disease fungi 



Insect and disease damage 

 can often be reduced by 

 planting seedlings of resistant 

 or tolerant species and using 

 local seed sources. 



The Future— 83 



