SPOKANE, Wash. – At Webster Park, the first windstorm knocked down three mature ponderosa pine trees. They all ended up pointed north, an evidence of the direction that powerful wind blew on July 23.
City of Spokane lead arborist Jeff Perry said the trees that went down were among the tallest in the park, but because they were so tall, they had more leverage. Those physics combined with rocky soil below caused the trees to snap at the roots and pivot in a socket.
In other neighborhoods, trees snapped off midway. In those cases, Perry said, the trees’ roots had more material to cling to underground.
“The winds were so high that the trees couldn’t withstand it,” Perry said. “Trees develop reaction wood, and if they’re not used to reacting to, let’s say those high winds, they don’t develop that reaction wood to deal with it, so we end up seeing the failure.”
Perry found that most trees he has checked on for risk assessments during the year were still standing after both windstorms because they were leaning, bent or twisted. He said it was likely that “reaction wood” that helped them resist the strong wind.
The city takes inventory of every single tree on public land or in the right-of-way, and in the coming weeks Perry will be revisiting hundreds of sites to help update the inventory of trees lost. Perry said, over time, they will replace each lost tree with two new trees. That means at least six new trees will be planted at Webster Park, giving the park more age variety in its trees.
Some of the trees were so large, the city will sell about three or four truckloads as marketable timber. The money made will be used in the replanting efforts. Additionally, limbs that are chipped will go back into the city park system. Some of the wood will also be stockpiled and donated to Snap to help heat homes in the winter.