birch bark borer intervention

This is my first post. Recently a street tree lost a limb and the City sent out a work crew to fix the problem. The employee told me that he could see that my birch tree (about 50 ft or more tall) had birch bark borers (dead leaves in the top several feet of two of its three trunks), and that the infestation was probably 10-15 feet below this point. It's close to the sidewalk and I don't want branches falling on passers-by.

I don't like to deadhead trees but I will be sorry to lose the beautiful bark. Is it possible or even worth it to have the tops cut off below this point to extend its life; can a tree company (any recommendations?) do that sensitively and give a reasonable assurance they have got it all. Or should I just have it taken down in the next year or two? Are there any other treatment options?

 

The bronze birch borer is an epidemic in the lower mainland and has been for many years. Legally, as this is a street tree on city property you are not allowed to touch it. You will be fined.

The city can cut the dead part off of the top of the birch if they believe it is a hazard with potential targets, or they could remove it and replace it with some-thing else.
In the mean-time, you can slow down the birch borer if you alleviate the heat stress that the street tree is experiencing. Water the tree (and all trees) well during your homes watering periods as outlined in your cities water bylaw.

This creates more water and sugar movement in the cambium layer of the bark and the bronze birch borer does not like this, as it cannot feed or tunnel as well.

If you run a hose across pedestrian access, please stay and monitor the watering. I am not responsible for giving tree care advice that may cause some-one to be injured.

 

Thanks for the information about watering discouraging the borer. I have been watering it a couple of times a week hoping it would help but I did not know the insect would not like it. That is good news. The tree is technically on City land because the front 10 feet of my garden belongs to the City, I believe, so I can continue to water it without hoses being a danger to anyone.

 

If the tree is in your yard under your care and not a boulevard tree owned by the city you may be able to hire a tree service to apply a trunk injectable insecticide. The issue is that a treatment is only an attempt at prevention and nowhere near a cure for the ailment. Irrigation will help keep the tree in a lower stress state.

 

http://vancouver.ca/bylaws9535c.PDF

 

Off the cuff I thought Vancouver's bylaw had an exception for trunk injectable insecticies as some of the other cities do, it appears that is not so. However, I know of a few companies using this exemption to apply pesticides and have yet to be challenged on the definition:

section 2.10

f) to control or destroy pests which have caused infestation to property, being the
presence of pests in numbers or under conditions which involve an immediate or
potential risk of substantial loss or damage;

ps, your link seems to have been a bit off, the link I looked at is: http://vancouver.ca/bylaws/9535c.pdf Probably just a typo.