Oregon experienced record drought in 2013 through 2015, followed by another year of dry conditions in 2016, and those severe conditions are taking a toll on conifer trees. It’s important to remember “a few drops of rain doesn’t end the stress of drought on trees,” said Lena Tucker, Deputy Chief of the Private Forests Division for the Oregon Department of Forestry. Symptoms of drought include foliage loss, dead branches, dead trees and tops. Drought-stressed trees are more susceptible to further damage by insects and other pathogens, and damage typically is most severe on the fringe of forested areas and on shallow or rocky soil types. Trees growing near roads, ditches, pastures, disturbed soil, or where there is competing vegetation are frequently affected. Symptoms are most visible during the spring following a drought event, although recent droughts have been severe enough for symptoms to appear in late summer or fall. People can take preventative care to help trees survive drought by doing the following: -Plant native and local drought-tolerant species; -Don’t thin stands during droughts; -Control vegetation (especially grasses) that compete for soil moisture; -Remove and destroy dead and dying trees, blowdown and slash to reduce insect infestations; -Avoid damage from machines and soil compaction; -Irrigate landscape trees during dry weather, applying water slowly or use drip irrigation lines; -Apply mulch to landscape trees to retain moisture; -Don’t alter drainage patterns (ditches, ponds, etc.) near established trees; -Don’t fertilize during drought conditions. Fertilization stimulates dehydrates trees.
