According to the Walla Walla District US Army Corps of Engineers, approximately 236 trees were planted along the trail when the levy was first built in the late 70's to help beautify the area. However each tree was planted in a eight-foot-wide by four-feet-deep concrete planter, meaning every ten to fifteen years the tree dies due to the containment.
"We don't normally want them there because it can hurt the integrity of the levy," said Walla Walla District U.S Army Corps of Engineers Natural Resource Manager Joseph Maxwell.
Planting the trees in cement planters allows the levy to have some vegetation along the trail, but often times roots will jump over the cement planters and will have to be cut off. Corps officials said the planters are designed to restrict any roots from breaking through the concrete pots but because of close quarters the tree's life span is much shorter.