(1) Whenever it is found with reasonable certainty that the infestation exists, he or she shall proceed as follows. If the tree inspector finds that the danger of infestation of other oak, elm, or ash trees is imminent, he or she shall notify the owner of the property on which the nuisance is found by certified mail addressed to the owner at his or her last known address that the nuisance must be abated within a time specified in the notice, but in no event later than April 15 of the following year. The tree inspector shall immediately report the action to the Council and after the expiration of the time limited by the notice, the tree inspector may proceed to abate the nuisance as herein provided. The cost of the abatement shall be assessed against the owner of the property involved or against the property itself.
(2) All oak trees within the city diagnosed as having oak wilt should be isolated from neighboring healthy trees of the same species by chemical or mechanical disruption of common root grafts to prevent the root graft transmission of the oak wilt fungus.
(3) To control the overland spread of oak wilt, the pruning of oaks shall be avoided during the most susceptible months of May and June. If wounding is unavoidable during this period, as in the aftermath of a storm or when the tree interferes with utility lines, an asphalt-based tree wound dressing shall be applied immediately.
(4) Trees of the red oak group diagnosed as having oak wilt may be girdled as soon as they are detected in order to speed drying and reduce spore production. Girdling shall be done only in areas where a weakened tree will not constitute a hazard to life and/or property should it fall. Trees included in this group are commonly known as red oak, pin oak, scarlet oak and black oak.
(5) To prevent oak wilt fungus spore production and control overland spread of this disease, any diseased material of the red oak group desired for use as fuel wood or to be salvaged for other purposes must be debarked or else completely covered by heavy plastic (four mil or greater) until July 1.
(6) Any branch or other material of the red oak group not to be salvaged shall be disposed of by burning, chipping or removal to an authorized dump site. The city forester shall advise accordingly.
(7) Stumps of trees of the red oak group removed due to oak wilt shall be completely covered, removed or debarked to the ground-line to eliminate all possibilities of spore formation and overland disease spread.
(8) Trees of the white oak group (i.e. white oak, bur oak) diagnosed as having oak wilt should be isolated by root graft disruption, as previously stated. Diseased material originating from the trees will not support spore formation and salvaged material therefore will not require special treatment to control overland disease spread. Standing trees of this group showing symptoms of minor oak wilt infection may have the infection successfully removed by selective pruning. The city forester will advise accordingly.
(9) Ash trees found to be infected with emerald ash borer must be treated and/or disposed of in compliance with all recommendations of the Minnesota Department of Agriculture and the Minnesota Department of Natural Resources.
(Prior Code, § 902.05) (Am. Ord. 07-10, passed 4-26-2010)