I have been recommending stump grinding with every tree removal on the public right-a-way. I am concerned that if a new tree is planted in the area of the ground stump that it will be susceptible to root rot,even if there is no rot in the old tree. Any wisdom? Mike Bowman

Reply to post by Mike Bowman, on January 31, 2000 at 17:41:54:

The big stress in planting in the same spot is that the decay prosses will use up all the nutrients.

Are you recomending removal of debris too, or allowing the site to remain "fallow" for a year or two?

Reply to post by Mike Bowman, on January 31, 2000 at 17:41:54:

Mike, at CSU, Chico campus we have a number of locations where there has been oak root fungus. Often it is associated with trees whose large roots were severed in the past in conjunction with sidewalk, curb, and gutter replacement. When some of these trees eventually fell or were taken down, the decision was made to have the stumps ground on-contract. Many times the job was not thorough, so large roots remained. Then trees were sometimes directed to be placed in the hole, often with the chips still there, without bringing in soil. So far I have not seen new trees show signs of infection, but I have read warnings that roots from the removed tree may harbor the organism, providing a base from which to attack the next plant. Besides this concern, I have a concern about planting in the chips, due to the competition between decay microbes and new tree for nutients, and also due to the possible subsidence of the tree as the organic matter under and around it loses volume through decay. I suppose that the trees could be supplemented with fertilizer, and the trees could be planted a bit higher, to deal with these issues. Since ORF seems to be endemic here, I wonder whether the concern should be less with the removal of old stump and roots, and more with preventing the kinds of root injury that lead to massive infection. Also, with the discussion about Tricoderma (?) I've read lately, I wonder what we can do to effectively enhance microbial interactions that may limit the population of ORF at the site.