Jamie Lusch / Mail Tribune Mike Oxendine of Plant Oregon Nursery shows a drip irrigation system that can be used to keep trees alive during drought in southern Oregon.
Most people water badly
Efforts to conserve water during the drought in southern Oregon could put trees at risk, especially since most people don’t know the correct way to water trees when they turn on the tap.
Most established trees draw their water away from their trunks. The nourishing roots that carry water and nutrients to the rest of the tree extend well beyond the tree canopy, said Mike Oxendine of Plant Oregon, a nursery outside of Talent.
“The thing we need to do to protect our trees the most is to keep watering deeply once a week,” he said. “Unfortunately, when we start to reduce our water, sometimes we reduce the water in the lawn and forget that our trees have been drawing water from this lawn for as long as they are alive. “
The best place to water trees is at their drip line, Oxendine said.
The drip line is the perimeter around a tree that sits at the outer edge of the canopy.
Oxendine said to visualize the drip line, imagine a glass of wine lying on a plate. The bowl that holds the wine is like the canopy of the tree, while the outer edge of the flared base of the wineglass is like the drip line. The plaque that extends from the bottom of the glass represents the nourishing root zone.
Rather than using a sprinkler, Plant Oregon recommends using a drip irrigation hose to release water drops around the tree’s drip line.
Drip irrigation tubes, also called pre-issued tubes, are available at hardware and garden supply stores.
Oxendine said the amount of water emitted from a drip varies, but a typical volume is four liters per hour.
This equates to about a gallon of water per hour.
In comparison, a standard garden hose delivers about 10 to 20 gallons of water per minute.
“It’s a pretty slow and constant drip, so you’re not using a huge amount of water at all,” Oxendine said.
Plant Oregon recommends people water their trees for up to three hours once a week using a slow drip system.
Jamie Lusch / Mail Tribune Mike Oxendine from Plant Oregon nursery near Talent extends a drip irrigation hose to water the trees.
Spreading mulch around a tree will help retain moisture and control weeds, Oxendine said.
Young saplings can quickly experience drought stress, but older, established trees often suffer from few red flags – at least initially.
“The bigger the tree, the slower the change will be,” Oxendine said.
The first year with too little water, a tree may wither, shed some of its leaves, and start to turn brown. As the stress of the drought continues into the second and third year, beetles begin to infest the tree – triggering secondary infections from mold, fungus and bacteria, Oxendine said.
This combination can prove fatal for trees, he said.
“Usually it’s the one-two punch that knocks trees out,” Oxendine said.