Valley’s tree population hit hard by dry winter, summer | AspenTimes.com

Valley’s tree population hit hard by dry winter, summer

Think you’ve got reason to be stressed this summer? Be thankful you’re not a tree.

Sunny weather last winter combined with heavy frost in May and now the drought have made life tough on trees in the Roaring Fork Valley, according to foresters and nursery managers.

From the stately blue spruce trees in Wagner Park to deciduous saplings along Aspen’s streets, the weather has taken a toll and it’s showing.

“We’re definitely seeing drought stress and even some mortality,” said Aaron Reed, forester for the city of Aspen. “We’ve been below average rainfall for a number of years.”

Some of the blue spruce in Wagner are droopy and sickly looking. Most of the damage was done before the sprinkler system was running. The damage has now plateaued, Reed said.

The recent rain helps, but Aspen has still only received about three inches of precipitation through the year – about a third of normal.

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Firefighters who battled the Coal Seam blaze in West Glenwood Springs last month said the moisture content was dropping to single digits and that some trees that appeared healthy were actually drier than kiln-dried, treated wood.

Trees in town that are regularly watered have fared better, but the weather and pests such as spider mites have teamed to kill some in Aspen. Two large cottonwoods were removed recently from Rubey Park due to mite damage, Reed said. And some younger trees along city streets were removed because they never had a chance to establish themselves before drought hit.

The city parks department is trying to cut its water use by about 10 percent this summer, so it is watering fewer times and for shorter durations.

Stephen Acker, the nursery manager at Eagle Crest in El Jebel, said the stress that trees are experiencing goes back further than this summer’s drought. There was so much sunny weather last winter that trees suffered from a condition that is the equivalent of sunburn for humans, he said. That damages and sometimes even splits the bark.

Then, as trees were leafing out they were hit by a hard frost in May, causing some to lose their leaves. Less than .5 inches of rain fell in May and June combined, so new growth has been curtailed as trees go into survival mode.

Ash, maple, dogwoods and cottonwoods were hit hardest. Even native trees such as blue spruce were affected. The frost knocked off needles, Acker said. Now the spruces are producing extra-high amounts of pine cones to propagate. The trees are sensing the drought and are safeguarding against dying off.

Deciduous trees are responding to the drought by shedding their oldest leaves.

Acker said that homeowners can help their mature trees best by thoroughly watering them once per week – but just once. Mature cottonwood and spruce trees suck up at least 75 gallons of water per day. But watering once per week is better than keeping the soil moist all the time because the tree also needs oxygen, he said.

Acker said on the watering day, run the hose until the ground is saturated and won’t hold more water, then turn it off, wait a while and repeat one or two more times.

Reed said the city parks department has changed its priorities due to the drought. It will concentrate on helping young trees survive rather than plant so many new ones. The city has planted about 300 new trees in the past three years in its street trees program.

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