Winds might back off but trees can still come down in coming storm

photo credit: Yuliya Krasylenko

Sonoma County experienced a tragedy this week when a 2-year-old boy died during Wednesday's storm after a tree toppled and crashed down on his family's home in Occidental. While fierce storms aren't new to the North Bay, the number of downed trees so far is unusual.

One local arborist has insight.

"Advice is your best friend," Fred Frey said. "Get someone who really understands trees to come out and look at them with you."

Frey is a certified arborist and owner of Vintage Tree Care in Santa Rosa.

"If that's not something that's at your disposal, look for those anomalous features in the tree," Frey said. "Is it leaning in a direction? You don't recall it? Is it missing a limb? Is a limb in a position you don't remember?"

"Look for pooling water. If you see a lot of water sitting beneath your tree, that can add to the saturation levels. See if you can keep the water diverted away from the, the tree itself so that it has a little bit more opportunity for the soil to stay firm."

Frey said there’s any number of factors that come into play when determining the health of a tree and the likelihood of a fall.

"It's very site specific," Frey said. "What's your topography like? Are you on the downhill side of several trees? The uphill side? Is it pretty level, the topography? What type of species are in existence? Are there several different species?"

"And then if you were to be on a site that had a preexisting stand of trees, say a native stand, within that stand, you're going to have superior trees, inferior trees, subordinated trees, dominant, subdominant."

Frey said the tree must be right for its location.

"Certain trees exist better to live in low light, high light, high wind, low wind," Frey said. "So really as you're managing a sand of trees, there's a lot of consideration given to exposure to the elements. And then you kind of couple that with the species and the species characteristics for risk failure, et cetera."

"It sounds lengthy. It's a pretty easy process, but there's no rule of thumb to give you, unfortunately."

The strong winds are predicted to recede in coming days, but not the possibility of more tree falls, Frey said.

"We've seen a little of everything," Frey said. "We've seeing a couple trees that have failed due to preexisting conditions that just couldn't sustain the wind loads.The simple math is this, when the force exceeds the strength of the plant, then you get the failure."

"Now that doesn't always lend to the tree buckling in half. It could have a cavity that finally failed. It could have decomposition that was alluding you, and it was expanding inside of the tree, and that caused it to fail. But most of the failures we've seen in this last few days that we've seen as our service is related to soil saturation. We're seeing trees fail because the soil was so saturated."