Oak Wilt #3

Garden Clippings for April 14, 2018

Sarnia City Council did an oops.  If they knew then what we know now, they would have approved the proposed tree preservation by-law at their October 2017 meeting.

At issue is Oak Wilt, a nasty pathogen that is busy attacking Oak trees in all the Northeastern States.  To date, the problem has not yet crossed the border, although experts say its only a matter of time.  Some say the problem is already here.

If there were a tree preservation by-law in place, homeowners would need to acquire a permit in order to cut down trees.  Cumbersome though that would have been, the City forestry staff would be able to control the timing of Oak tree removal.  Without a by-law that level of protection does not exist.

With or without a by-law, we can expect that some unsuspecting homeowner will borrow a chain saw and trim or chop down an oak tree without realizing the consequences.  Today, education is the best defence against the introduction of Oak Wilt into Ontario.

In last week’s Garden clippings, I wrote that the pathogen affecting Oak trees needs a sap beetle to move and spread the fungal spores from infected to healthy trees.  The beetle needs an open wound or fresh cut to obtain a point of entry into an unaffected Oak tree.  The sap beetle will only do the deed in the period just prior to leaf flush and after leaves are fully developed.

To be on the safe side, Oak trees should not be pruned or cut down during the months of April, May, June, and July.

If it is absolutely necessary to cut Oak trees, perhaps for safety reasons, apply tree wound paint over the fresh cut.  Don’t wait till after lunch to apply tree paint but do so within minutes.  If an Oak limb breaks during a windstorm, make a clean cut as soon as possible and apply tree wound paint to seal the spore openings.

Be careful when cutting the grass at the base of an oak tree.  Even a line trimmer can create an entry point.  Putting down a mulch ring at the base of a tree will provide protection from mechanical injury.

For those who need to cut down trees, consult with and hire a professional arborist who is well versed in Oak tree issues.  Don’t be tempted to hire a fly by night tree cutter who wants to make some quick cash.

Do not move firewood.  The Canadian Food and inspection Agency has strict rules and guidelines regarding the buying and moving of firewood.  No firewood is permitted to cross borders.  Firewood that is cut locally ought to remain local.  Many Canadian National parks prohibit firewood from entering their grounds.

If you suspect an Oak tree on your property may be affected by Oak Wilt, call the CFIA and they will follow up with a visit.  The most visible sign of Oak Wilt are browning sections of green leaves, starting at the outer perimeter of the tree.  Oak Wilt is easily confused with Anthracnose which often shows symptoms of leaf browning beginning in the inside of the tree.