Drought erasing evergreens from palette of Great Plains - Omaha.com
Published Wednesday, March 20, 2013 at 1:00 am / Updated at 2:10 am
Drought erasing evergreens from palette of Great Plains
Protect your trees from drought
» De-emphasize grass under trees. The watering, fertilizer and pesticides that create a lush lawn are hard on trees.

» Widen mulch bed significantly; widen to a 12:1 ratio; 12 inch outward extension of mulch per 1 inch diameter of trunk.

» Lay mulch at depth of 3 to 4 inches, but no more.

» Water infrequently but deeply, no more than two times a month.

» Don't drive on lawn; soil compaction suffocates trees.

» In communities where water restrictions are likely, don't habituate trees to frequent watering.

» Do not fertilize.

» Chemical treatment won't resolve most drought-related disease and pests, so focus on tree health.

» Lost a tree? Replant as part of a tree-friendly ecosystem, not as a single tree in isolation.

Source: Nebraska Forest Service

What trees to plant?

Shade Trees
» Oaks (bur, red and chestnut)
» Elm (Triumph, Frontier, Princeton)
» Pecan
» Miyabe maple
» Sycamore
» Hackberry
Evergreens
» Pines (ponderosa, Bosnian, Korean)
» Fir (Douglas)
» Spruce (Meyer)
Companion plants

In place of lawn, landscape with mulch and sun-tolerant flowers and grasses, followed by shade-loving ground cover and shrubs as trees mature.

Source: Nebraska Forest Service

Evergreens, with their splash of green in drab Nebraska winters, have become the first to die as historic drought and its shadow, climate change, redefine the trees that can survive the Great Plains' extreme weather.

Nearly 700 pines in Lincoln's iconic Pioneers Park have died since July. Other parks across the state are losing trees, too. In neighborhoods, the deaths are more isolated, as first one tree, than another dies.

Deciduous trees, those that shed their leaves seasonally, are struggling too, but they have more ways to adapt.

The rapid decline of trees, even species believed to be hardy enough to survive in Nebraska, is worrisome given that another hot, dry year may be unfolding.

“If it was that bad in one year, what if we have something similar this year?” said Eric Berg, a community forester with the Nebraska Forest Service. “It's going to be devastating.”

As the drought takes its toll, the Nebraska Forest Service is re-evaluating the recommendations it makes to Nebraskans, Berg said. The revisions are made more difficult by climate change.

“Drought will refine our recommendations, but the greatest challenge is the climate is changing,” he said.

In the past, foresters have considered winter, not summer, as the limiting factor on tree survival in Nebraska. A tree had to survive a temperature plunge from 70 degrees on one day to 15 degrees the next, so foresters recommended northern seed sources, Berg said.

But Nebraska is warming at an accelerating pace, so state foresters have begun looking southward for new tree species. To this end, the Nebraska Forest Service is working with its counterparts in Kansas to develop new recommendations for the Central Plains, Berg said.

If only it were that simple, he added.

Nebraska will continue to see extreme temperature swings even as its climate warms, so foresters aren't sure whether to look north, south or overseas for seed stock.

“I don't think we'll ever get an answer to that,” he said. “The answer is probably going to be more diversity.”

In the broadest terms, the start of this drought has disproportionately claimed evergreens, said Justin Evertson, also a forester with the Nebraska Forest Service.

White pines have been hit worst, and arborvitae aren't far behind.

Spruces have begun to suffer from a combination of drought and humidity. Declines are being seen in green, blue and Norway spruce. The popular and regal scotch pine was already being wiped out by pine wilt.

Evergreens have been especially vulnerable because so few are native to Nebraska.

The aggressive, unattractive red cedar is the closest native evergreen for the Omaha-Lincoln area, Evertson said. And even those trees are beginning to die from drought.

“The way the climate is shifting in eastern Nebraska, we'll have fewer evergreen choices,” he said. “We'll probably continue to lose evergreens at a fairly alarming rate.”

That doesn't mean that people should give up on evergreens or that foresters will stop searching for suitable species, he said. Instead, those planting several trees should weight their selections toward deciduous trees.

“There's a fine line between alerting people to our concerns about drought and trees, but not scaring them,” Evertson said.

“There are so many challenges. If I was the average person looking at this, I'd think, 'Why should I plant a tree?' Trees are hugely important to making our cities livable and attractive.”

Evergreens have been dying faster than deciduous trees because they're less able to cope, said Graham Herbst, also a forester with the Forest Service.

A deciduous tree can drop its leaves when under stress and then bud new ones later. A pine can't drop and later replace needles. Likewise, deciduous trees have a nourishing layer inside their bark that evergreens lack.

White pine, Herbst said, are dying first because their thinner needles are more vulnerable to winter's drying winds.

Eastern Nebraska's humidity encourages disease among evergreens in way that doesn't happen farther west, he said.

The fingerprints of climate change last summer were on the high number of warmer-than-normal nights, climate experts have said. In addition to chronic warmth — the year was the hottest and driest on record in Nebraska — Omaha and other communities set nightly records for warmth.

This is a problem because trees rest at night and replenish lost moisture. If nights are too warm, trees don't have the chance to recover and instead continue to function as if it were daytime, using up water. In the long term, that weakens the tree and makes it more vulnerable to disease and pests.

Like evergreens, deciduous trees are encountering problems, but those tend to be the result of planting or care, Evertson said.

A notable example is the popular river birch.

The species thrives in protected wet environments, but it is often planted in sun-baked, windswept new developments and mulched with heat-absorbing river rock. Individual river birch planted in such conditions are struggling, the foresters said, while others placed in more protected areas, well-watered and properly mulched are doing better.

“Drought is not indiscriminate,” Evertson said. “It takes out trees least acclimated to an area, and it will take out those that are compromised for other reasons.”

Foresters, he said, are learning along with the public.

“Most trees are pretty naturally drought tolerant, that's what has been surprising to me,” Evertson said. “We're going to learn some things as we watch these old soldiers fall.”

Contact the writer: 402-444-1102, nancy.gaarder@owh.com

Contact the writer: Nancy Gaarder

nancy.gaarder@owh.com    |   402-444-1102    |  

Nancy writes about weather, including a blog, Nancy's Almanac. She enjoys explaining the science behind weather and making weather stories relevant in daily life.

Crew working to disassemble International Nutrition plant
Woodmen request would take nearly $40M in valuation from tax rolls
New public employee pay data: Douglas, Lancaster, Sarpy Counties, plus utilities
Arrest made in teen's shooting death at Benson's Gallagher Park
Section of 50th Street to close for bridge demolition
18-year-old arrested in stolen-car case
U.S. Senate candidate Bart McLeay trails his 3 GOP rivals in fundraising
86-year-old Holdrege man killed in weekend collision
New police gang intervention specialist knows firsthand about getting involved with wrong crowd
Finally. Spring expected to return. No, really: Warmer-than-average weather in forecast
Four, including Omahan, vie for police chief position in Council Bluffs
In TV ad, Shane Osborn says Ben Sasse 'beholden to Washington'
City Council OKs redevelopment plan for north downtown project
Rather than doing $250K in repairs, owner who lives in lot behind 94-year-old house in Dundee razes it
Kelly: New $24M UNO center embodies spirit of newlywed crash victim
Home alone: When burglar broke in, 12-year-old locked herself in bathroom, called 911
High school slam poets don't just recite verses, 'they leave their hearts beating on the stage'
Ben Sasse raises more money than U.S. Senate foes Shane Osborn and Sid Dinsdale
Sweet deal on suite use has MECA board looking at written rules
Inmate accused of partially tearing off another's testicles charged with assault
Lawyer: Man had right to hand out religious fliers outside Pinnacle Bank Arena
Firefighters put out duplex blaze in N.W. Omaha
Coffee with a Cop set for Thursday in Benson
Douglas County offices accepting credit, debit cards
Parched Omaha soil soaks up record precipitation
< >
COLUMNISTS »
Kelly: New $24M UNO center embodies spirit of newlywed crash victim
Jessica Lutton Bedient was killed by a drunken driver at age 26 in 2010. Thursday, the widowed husband and other family members will gather with others at the University of Nebraska at Omaha to dedicate a permanent memorial to Jessica.
Breaking Brad: What do the moon, Colorado senators have in common?
How about that "blood red" moon Monday? It was as red as the eyes of a Colorado legislator.
Breaking Brad: Hey, Republicans, are you ready to be audited?
A quick list of audit red flags: 3) You fail to sign your return. 2) You fail to report income. 1) You are a registered Republican.
Breaking Brad: Next year, Bo Pelini brings a mountain lion to the spring game
Before the spring game, Bo Pelini carried a cat onto the field. With Bo's personality, it'd have been more appropriate for him to carry a mountain lion.
Breaking Brad: Bo Pelini's cat lets spring game intro go to its head
Coach Bo Pelini took the field before the spring game holding a cat aloft. Typical cat. He was undoubtedly thinking, “Sixty thousand people, all cheering for me!”
Deadline Deal thumbnail
Shoreline Golf Club
$40 for 2 Players, 18 Holes of Golf with Cart ($85 Value)
Buy Now
PHOTO GALLERIES »
< >
SPOTLIGHT »
Omaha World-Herald Contests
Enter for a chance to win great prizes.
OWH Store: Buy photos, books and articles
Buy photos, books and articles
Travel Snaps Photo
Going on Vacation? Take the Omaha World-Herald with you and you could the next Travel Snaps winner.
Click here to donate to Goodfellows
The 2011 Goodfellows fund drive provided holiday meals to nearly 5,000 families and their children, and raised more than $500,000 to help families in crisis year round.
WORLD-HERALD ALERTS »
Want to get World-Herald stories sent directly to your home or work computer? Sign up for Omaha.com's News Alerts and you will receive e-mails with the day's top stories.
Can't find what you need? Click here for site map »