February 07, 2003
Mulching, Watering Key to Tree Survival During Drought
LINCOLN, Neb. — Dry winter weather and persistent drought have stressed many of Nebraska's trees, but mulching, watering and landscape adaptation can prevent further decimation, University of Nebraska foresters say.
Doak Nickerson, district forester at NU's Panhandle Research and Extension Center at Scottsbluff, emphasized managing dry trees with mulch, anti-transpirant spray and water.
"The importance and benefits of mulching are even more pronounced in times of drought," he said. "Mulching of any kind conserves existing soil water for the next growing season and reduces the time, energy and expense of supplemental watering in addition to increasing tree planting survival."
Snow cover also serves as natural mulch, but it won't reduce the impact of the state's drought, said David Mooter, NU program leader for community forestry for the Nebraska Forest Service in Omaha. The state would need two to three years of average precipitation for conditions to return to normal, he said.
Anti-transpirant spray helps seal evergreen foliage from moisture loss and prevents winter desiccation, sand blasting and wind burning, Nickerson said.
"Winter watering is a fine art," he said. "The winter weather conditions of the Front Range in Colorado are very similar to what we face in western Nebraska and the rules of winter watering of trees apply."
Up-to-date information on water recommendations for western Nebraska can be found on the Colorado Forest Service Web site.
Watering trees by hand is best, said Rachel Allison, community forester assistant for the Nebraska Forest Service.
Water should be applied across the soil surface, gradually letting it soak in. Surface soaking allows tree roots more chances to absorb water, maintain soil health and maintain nutrient cycling in the soil, said Allison at NU's West Central Research and Extension Center at North Platte.
Broadleaf trees lose water at a reduced rate during the winter, but continue to need water to perform basic physiological functions. Evergreens may require even more attention.
"Evergreen plants such as pines, spruce and yews may require watering because they continue to transpire or lose moisture throughout the winter," Allison said. "Plants such as viburnum, dogwood, maple or linden may need more water than species like honeylocust, oak or hackberry, which are better suited to Nebraska's dry, continental climate."
Steve Rasmussen, Nebraska Forest Service district forester at NU's Northeast Research and Extension Center in Norfolk, is not recommending large-scale watering for dormant trees and shrubs in northeast Nebraska.
"The northeast section of Nebraska is not as dry as other areas due to rains in August and October," Rasmussen said. "We received about 88 percent of normal precipitation this past year which is why I do not consider it a live threatening situation for the dormant trees and shrubs. We have not had the extended 24 months of dryness like western Nebraska. If we continue to be dry, we will have trouble for the trees and shrubs, but right now there is enough subsoil moisture to get us through the winter," he said.
Once plants start growing again next spring, watering will be crucial, he said.
During the drought, Allison recommends adapting or re-landscaping the urban lawn to benefit trees. Homeowners may want to consider beneficial landscape goals such as incorporating trees and shrubs into wood-chip mulched beds, separating the watering systems between lawn and landscape areas and selecting plant materials that will do well in their area.
2/7/03-CM
David Mooter
Nebraska Forest Service
Forester
(402) 444-7804
Doak Nickerson
Nebraska Forest Service
District and Extension Forester
(308) 632-1238
Rachel A. Allison
Nebraska Forest Service
Community Forester Assistant
(308)532-3611 Ext. 161
Steven D. Rasmussen
Nebraska Forest Service
District Forester and Great Plains Initiative Coordinator
(402) 375-0101
Christine Meyer Forestry Information and Education Specialist (402)472-9869
Department: Nebraska Forest Service|School of Natural Resource Sciences
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