Emerald ash borer (EAB) infestations are difficult to identify in the early stages of the infestation. Emerald ash borer infestation areas grow via human-assisted movement and through natural dispersion. For these reasons, when new emerald ash borer infestations are discovered, quarantines are enacted on a large scale (county) with the assumption that the infestation is spread beyond what is observed. However, while the quarantine necessarily covers a large area where emerald ash borer may be present, the distribution of emerald ash borer is likely not uniform throughout the quarantine and may be in areas outside these boundaries.
These guidelines ideally should be followed 100 percent of the time when working with ornamental or urban ash trees throughout the state of Minnesota. However, once an area is considered generally infested* with emerald ash borer, conducting ash tree removals during the emerald ash borer active period may be necessary to avoid risk to public safety and property. Following these guidelines will provide the lowest degree of risk for movement of emerald ash borer.
Guidelines
EAB Active Period - May 1 through September 30
- Avoid removal of ash branches, trees, and stumps**
- If removal is necessary due to a hazardous condition or being in a generally infested area, then,
- Chip the outer 1” of bark/wood from ash logs on-site and transport to the nearest facility that can quickly process the material, if necessary*** or
- Transport logs and branches (as small as 1 inch in diameter), ideally enclosed, to the nearest facility that can quickly process the material.***
EAB Dormant Period - October 1 through April 30
- Conduct ash branch, tree, and stump removal as desired.
- Transport ash logs, branches, and stumps to a facility where they will be processed*** prior to May 1.
Explanations
*Generally Infested
- Point at which EAB infested ash are widespread and many ash are already weakening and becoming hazardous.
**Active vs. Dormant Period
Branch / Tree / Stump removal should be avoided during the EAB Active Period for two reasons:
- When an infested ash is left in place during the EAB Active Period, EAB often will re-infest it and not fly farther beyond the currently infested area. When these infested ash are cut and properly disposed of*** during the EAB Dormant Period, EABs within the tree will be destroyed.
- Material moved during the EAB Active Period may release adults at any time during transportation into a previously un-infested area.
***Disposal of outer 1” of bark/wood vs. whole tree
- Only the outer 1” of bark/wood harbors EAB. If this material is removed, the remaining wood may be utilized as desired and does not need to be destroyed.
- Options for effectively treating the material include grinding to a small diameter (less than one inch in two dimensions), burning or burying.
