Workshop to discuss weather-damaged trees, if they can be saved
BY BRAVETTA HASSELL World Scene Writer
Saturday, November 10, 2012
11/10/12 at 5:33 AM
The damage to this year's trees doesn't look anything like that done by the ice storm of 2007. But let the dry conditions continue, a powerful windstorm blow through or a rough winter descend upon the area and see how fast the effects of two consecutive droughts begin to show.
"It's not obvious now, but our urban forest has undergone an event - a series of events that rival that ice storm," said John Kahre, a professor of horticulture at Tulsa Community College. "The only difference is, instead of being on your car, (the damage) is still standing, and it will continue to stand for at least a while."
According to the NOAA National Climate Data Center, this past summer makes the second consecutive summer Oklahoma has experienced severe to extreme drought conditions and higher than normal or record temperatures.
City of Tulsa urban forester Michael Perkins said his office has been fielding 25 to 30 calls a month over the last four months from residents concerned about hazardous-looking trees in public spaces of their neighborhoods. Compared with the 10 calls a month that he and his colleagues were responding to at this time last year, it's a "large" increase, Perkins said.
"Last year started some stuff, and this year it's just really escalated once this extreme heat and drought set in on us," Perkins said.
Part of the surge in calls can likely be attributed to what Perkins calls a monoculture of trees in communities in Tulsa - that is, a lot of the same kind of tree. Many of those trees are drought-vulnerable.
Another part has to do with the positioning of the trees in yards and communal areas.
Still, the over-arching cause behind the uptick in phone calls is that it's just been plain hot. Hot and dry.
Unbearably hot and dry for human beings but for a tree?
Confronted not only by insects and disease, natural environmental occurrences and climate change, but also development and air pollution, "a tree is struggling just to be here," Kahre said. "And then you stress it with no water, and well, it will check out a lot quicker."
This gradually growing problem is why Kahre, Perkins and others will be talking "Landscape CPR" at 7 p.m. Tuesday at the Tulsa Garden Center, 2435 S. Peoria Ave.
During the workshop - a collaborative effort that includes officials from AEP-PSO, OSU Cooperative Extension Office and the Tulsa Garden Center - horticulture experts will discuss what the recent bad weather has done to Tulsa's urban forest, how residents can determine whether their trees have been damaged by the drought conditions and whether their trees can be saved.
Kahre and Perkins took the Tulsa World through midtown and south Tulsa to show examples of trees severely damaged by the drought.
In the 800 block of South Quincy Avenue, Perkins assessed one tree a resident had called in and an adjacent one that was in almost as bad a shape.
The tree didn't look good. Barren at its highest points, with green leaves in others, the tree is definitely in danger of shedding branches onto the street, Kahre pointed out.
The tree is a silver maple, a species of tree that Perkins said accounts for at least 90 percent of the calls he's received.
Silver maples are shallow-rooted and are especially vulnerable to extreme weather elements.
"With the drought, those surface roots are just desiccating out, causing the tree to start dying out from the top," Perkins said.
The struggling parts are green, but they are the minority. At least 80 percent of this tree was dead, Perkins said. When it reaches that point, "the whole tree just needs to come out."
Ken Preaus, co-owner of Preaus Landscape, suggested bringing in an arborist to determine whether a drought-stressed tree is salvageable.
But there are some observable signs that indicate stress.
Scorched and tattered leaf margins, compromised color, thinning crowns and twig and branch dieback are visible signs of a problem, he said.
And in the worst-case scenario, when heirloom trees can't be saved, emotions can run high, Preaus said.
In that case, he often recommends that clients consider planting a replacement tree in the landscape before their declining tree dies.
"It is far less painful to see the 'old-timer' go when their new tree is established, growing rapidly and gaining value every year," Preaus said. "Sometimes it may be possible to propagate a direct descendant of the declining tree via cuttings, suckers (from the root or base), or from a seed."
But it all starts with paying some attention, Kahre said. Another bad summer in Tulsa won't be good. It might not happen that way but, added Kahre, "We need to prepare ourselves for that possibility."
What is an urban forest?
According to the U.S. Department of Agriculture's Forest Service, an "urban forest" is any publicly and privately owned tree within urban and community boundaries.
What do trees in urban forests do?
Among a variety of functions, they:
- conserve energy
- remove air pollution
- raise property value
- reduce storm water runoff
- offer a cooling effect
- shade cars and parking lots, reducing ozone emissions from vehicles
- reduce noise pollution
- provide habitat for many species
- give humans oxygen
Heat-and drought-intolerant species
- Emerald green arborvitae
- Green giant arborvitae
- Colorado blue spruce
- White pine
- Austrian or Scotch pines
- Leyland cypress
- Southern magnolia
- Taxus (various yew species)
- Deciduous shade trees
- Silver or red maples and crosses of these species
- Norway maple
- White or green ash
- Honey locust
- Japanese maples
- Ornamental cherries
- Specific varieties of redbuds
Heat- and drought-tolerant species
Preaus Landscape's Ken Preaus suggests consulting the OSU Cooperative Extension Center, tulsaworld.com/osuextensioncenter, to find out what grows best in our climate, as well as in whatever soil type exists at your property.
Source: Ken Preaus, Preaus Landscape
Finding help for your landscape
The Tulsa Garden Center, in collaboration with the OSU Cooperative Extension Office, Tulsa Community College, Up With Trees, the City of Tulsa and AEP-PSO, presents "Landscape CPR: Lifesaving Measures for Drought-stressed Trees and Wildlife Habitats."
The event starts at 7 p.m. Nov. 13 in the Tulsa Garden Center auditorium, 2435 S. Peoria Ave.
During the two-hour information session, Tulsa homeowners will learn to evaluate the health of their trees and shrubs, recognize stress factors and provide solutions for the well-being of their outdoor living spaces. Also at the workshop, three-gallon trees in a variety of species will be available for a $5 donation.
The workshop is free and open to the public but advance registration is encouraged as seating is limited.
For more information or to register, call 918-746-5125
If you have concerns about a tree on your property that looks hazardous and potentially stressed, Ken Preaus recommends the following steps.
Call a professional arborist for expert advice and consultation.
Read as much information as you can at the OSU Extension, tulsaworld.com/osuextensioncenter, before doing anything yourself. Stay off ladders if you decide to perform the lighter work.
Watering: Newly planted trees require slow watering that will allow penetration of moisture to a depth of 8 to 12 inches. Use soaker hoses, gator bags, buckets with small holes drilled into the bottom, root feeders, irrigation systems fitted with bubbler emitters, etc.
Over-watering usually happens with automatic irrigation systems. It is important for people to "know" and not assume how much water they are applying and at what depth. "Too wet" conditions lead to low oxygen and poor gas exchange.
Mulch and landscape design: Trees grow in forests, not prairies, so simulate conditions in the forest. Eliminate turfgrass competition where possible - add 3 to 4 inches of mulch instead.
Fertilizer: Never fertilize trees without soil testing first to determine levels of fertility - either deficiencies or too much of specific elements. Manage soil pH and fertility issues by prescriptive applications as per the soil testing.
Original Print Headline: Tree damage
Bravetta Hassell 918-581-8316
John Kahre (left), with the TCC Horticulture Dept., and Mike Perkins, urban forester for the city of Tulsa, evaluate damaged trees near 68th East Avenue and 50th Place, on Friday, Nov. 2, 2012. CORY YOUNG / Tulsa World
Split wood is evidence of a dead tree. CORY YOUNG / Tulsa World
Curled and browned leaves are evidence of drought stress. CORY YOUNG / Tulsa World