Stating the obvious – planting trees on freeways is a challenge. One challenge is protecting trees from Caltrans mowing, which is a necessary practice to reduce the threat of roadside fires from discarded cigarettes. Following Caltrans advice, the trees we plant on freeways are caged in welded-wire fencing that is supported by three two-inch round lodgepole pine posts.
This year winter rains fueled the grass to grow almost six-feet, making it very difficult even for us to find our young trees on Tree Care Days, even with the cages. In May, Caltrans mowed down the tall grass. When we watered in June we found the mower ran over a Blue oak, crushing the wood posts and mangling the welded-wire fencing. The Blue oak was flat on the ground, but flexible to be put upright with tree posts. The caging worked.
We weren’t out of the woods yet, so to speak. In August we watered our freeway trees and found that Caltrans had mowed again. The mowers ran over another Blue oak, with the same result, the cage was destroyed by the tree bent over and survived.
The cages seem to provide enough protection for the young trees. Hopefully they will get big enough soon so the mowers will see them no matter how high the grass gets.