Bad year for live oak trees

A decade a ago, I was the first arborist called to the scene of some Coastal Live Oak mortality out at a ranch in Boulevard. There were no exit holes around the trunk indicative of California Live Oak beetle infestation that will often kill stressed trees. No other fungal infestations. In short, nothing out of the ordinary.

The owners were growing alfalfa, which uses copious quantities of water to grow to harvest. So I thought and told them that the water table must be dropping as the trees had died of water stress.

The next year they cut a few of these dead “live” oaks down for firewood. They saw some smaller holes higher up than what I had explained to them was the norm, so I went out to have a second look. I saw a new type of beetle’s galleries under the bark where the cambium layer had been stripped.

I should have been in panic mode but I told them that this is a new pest and that they needed to call the county agricultural department right away.

This government agency was so jaded by all the calls they get about normal dead and dying trees that they could not and did not respond for three years. By then the new beetle — or “Gold Spotted Oak Borer” (GSOB for short) had spread to the neighboring ranches and had no chance of containment.

Not to begrudge our County Ag Department, but if I had told the owners to call a private for-profit reputable tree spraying company, we may have never known about this new and very real threat. Live and learn. I am doing all that I can to mitigate the situation now nine years later.

I provide tree health but do not spray. I address tree health through tree/soil relations using aeration and beneficial endo myccorhizal fungal inoculation of the trees rhyzome. This is all we have left to fight this new pest, as there are no remedies and the county, state and federal governments are not planning to produce any. So we owners of live oaks are on our own. This is going to be a very bad year indeed for our oak trees.

Last year the GSOB killed hundreds of specimen live oak trees in Ramona, as the beetle prefers the larger trees first. Here we are in April 2015 and the beetle has just emerged from hibernation and is on the move.

Thomas Stephan is a Ramona resident and arborist.