[Durham INC] “Banding Together” to Protect Durham’s Urban Forest; four easy steps

[John Schelp]

“Banding Together” to Protect Durham’s Urban Forest

By Alex Johnson (Durham Forestry), HeraldSun.com, October 2013

After the hot and dry conditions of the past week it feels like fall is finally here, and this might trigger a few shopping trips for seasonal items. While stocking up on leaf bags and pumpkins, you may want to add a few unusual items, especially if you live in areas where canker worms were active this past spring. 

If you are wondering if you had cankerworms, they were hard to miss. Back in March and April when they were active, most likely they were in your hair, on your car, dangling from branches and munching on your shrubs.  Unfortunately, the time when we are most grossed out by them is when they are most difficult to control.  The time for proactive measures is between Halloween and Thanksgiving, and this is done by “banding” trees.  


The bands are barriers to keep adult moths from climbing up trees (the females can’t fly) to lay eggs.  No eggs, no caterpillars. [See photo & 4 easy steps below]

Adults emerge from their cocoons when the weather turns cold. Materials used can vary from specifically designed materials to whatever you find at the store (or in your basement or shed) that you can attach to your tree and coat with something sticky. 

When the bands are up they need a layer of goo called Tangelfoot. The sticky stuff traps the adult females. The best time to apply is after the leaves have fallen so the leaves themselves don’t create a path across the glue. Be sure your band is on tightly so the females can’t squeeze under the bands. Considering the number of trees, the problem can seem overwhelming and it can seem like a lot to expect from residents who wish to protect all of their trees.  This may leave you wondering why Durham isn’t doing more to help?

Durham will be banding some trees, but the City’s Urban Forestry Division will also be active in other ways, especially because fall and winter are planting seasons. For those entrusted with its care, Durham’s urban forest is more than the sum of its parts; it’s a complex ecosystem where concerns must be prioritized and addressed over an extended timeframe within a context of limited resources. 

The canker worm’s range extends from Canada to Texas, but only in Charlotte has this pest risen to the level where a major intervention has been initiated.  Charlotte has chosen to address the pest through aerial spraying and coordinated tree banding efforts which have lasted over twenty years. 

It turns out that Charlotte and Durham both have an “even-aged monoculture” of willow oak; a forest whose dominant component is made up of one species which is relatively uniform as far as its age. These ecosystems are rare in nature because they are inherently vulnerable.

In natural ecosystems, native pests that single out one host do not increase in number year after year because there are a variety of tree types in the overall population. To decrease numbers of canker worms, instead of focusing exclusively on fighting the pest, Durham’s trying to keep the pest in check while simultaneously changing the forest. That means replacing willow oaks as they die out with other species that the worms don’t prefer. Durham’s planting program has featured less “worm friendly” trees over the past five years. 

We certainly don’t wish to see our venerable willow oaks go. They have served us well for many years, and we willingly acknowledge a duty of care to keep them healthy as long as possible. However, the opportunity cost of mounting a Charlotte-type effort would significantly hamper the tree efforts that the City is undertaking, because the time for banding coincides with the time for planting.  


For more information on banding trees, email durhamcankerwormcontrol at gmail.com

***

Four easy steps (from neighbors in Old West Durham)...

1st: Get the cotton strips, band strips and Tanglefoot goo
 from Stone Brothers. Costs about $10 per tree.

2nd: Staple the cotton strip to your tree -- about shoulder level. 

3rd: Staple the band strip on top of the cotton strip. (The cotton is to keep the wingless females from crawling up under the tree band.)

4th: Apply the Tanglefoot goo on top of the band strips -- before November 15. That's when the moths start crawling to the tops of trees to lay eggs around here.
       
You can see some of our cankerworm bands at 1020 and 1021 Rosehill Av (near Englewood Av).
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