Start early to manage redcedar trees
September 5, 2013
Eastern redcedar trees may be a welcome sight to some Nebraska landowners – unless they've started taking over pasture and rangeland.
University of Nebraska/Lincoln Associate Professor of agronomy and horticulture Stevan Knezevic says landowners need to establish a management strategy for keeping eastern redcedar trees from spreading to grasslands.
"Eastern redcedar is native to just about every state east of Wyoming and the Rocky Mountains," Knezevic says. "They're very resilient in the Nebraska climate and resistant to all kinds of disease and insects. They start out as a very small seedling. That's the stage when landowners should implement a management plan to keep the trees from spreading across pastures. The smaller they are the easier it is to kill them."
The first historic accounts of eastern redcedar in Nebraska place them primarily along the steep valley of the Niobrara River in northern Nebraska. They were described as a minor component in eastern Nebraska's deciduous forests and a dominant species on canyon sides in the Loess Hills region of central Nebraska.
“No grass will grow for at least three feet around the base of larger eastern redcedars... they take a significant amount of moisture away from surrounding forage,” Neb. rancher Scott Stout
Recommended Stories For You
"If you want land for wildlife or hunting, you're probably very happy with eastern redcedar," Knezevic says. "Some landowners harvest the tree because it's a hardwood that doesn't rot as quickly as other woods. It's used for fence posts, siding and decking among other things."
Curtis, Neb., rancher Scott Stout uses prescribed burning to manage eastern redcedar on his rangeland. The practice helps him control spread of the trees when many of them are in the seedling stage. However, burning can be used to remove larger trees.
"If we're burning an area with larger eastern redcedars, we cut small ones and stuff them around the base of the large trees before we begin the burn," Stout says. "That way, there's fuel to get the larger tree started on fire."
Stout notes that there is a "death base" around each tree that reduces the amount of forage available for grazing.
"No grass will grow for at least three feet around the base of larger eastern redcedars," Stout says. "No matter what size the trees are, they do take a significant amount of moisture away from surrounding forage."
One unique trait of eastern redcedar is the production of male and female trees. The females produce berries, abundantly distributing seed.
"Landowners can destroy the female trees when they're small as one means of controlling their spread," Knezevic says.
If landowners don't suppress the trees when they're small, eliminating them can become a major effort and economic investment.
"Developing a management program based on the best combination of methods for a particular site will give landowners the most effective management plan," Knezevic says. "That could include mechanical, biological and/or chemical practices."
Managing well established tree infestations that developed over several decades requires a multi-year, ongoing effort. The main goal should be to reduce the number and size of the trees since eradication is economically or physically impossible in most cases.
"At low levels, eastern redcedars can be viewed as a potential resource, providing livestock shelter, wildlife habitat, timber products and aesthetic values," Knezevic says. "Most importantly, long-term selective management is considerably less expensive than an intensive, short-term approach."
Digging, cutting and mowing trees up to two feet tall is an effective mechanical control. Because eastern redcedar is a non-sprouter, trees cut below the lowest branches won't regrow.
"Trees larger than three feet tall require a chain saw or vehicle-mounted shears," Knezevic says. "Equipment varies from tractor-pulled PTO-driven shredders to hydraulic drive devices that mount on skid steer loaders."
Sawing larger eastern redcedar trees can be hazardous because the trees lower branches can cause injury to the saw operator when the tree falls.
"The cedar eater can be mounted on an ATV," Knezevic says. "The operator drives the unit into a tree and the blades cut the tree off, leaving just a flat stump."
Cutting trees can be time consuming and labor intensive. In addition to cutting, trees must be removed from the site because the skeletons of fallen trees occupy 70 percent of the space of living trees.
"In the past, some landowners have used prescribed burning as a management tool," Knezevic says. "That isn't effective for larger trees. Safety is also a concern since many managers lack experience with fire and the equipment required to implement that kind of fire."
As part of their management plan, landowners are encouraged to determine how many surviving trees they can tolerate. Low numbers of surviving eastern redcedars have a minimum effect on productivity and could provide a source for fence posts, paying for their own removal.
"Low numbers of eastern redcedars also provide livestock shelter and improve habitat for popular game animals such as deer and wild turkey," Knezevic says.
Herbicides shown to effectively help manage eastern redcedar include Surmount, Grazon P&D and Tordon 22K.
"Broadcast application is the most common method of applying herbicides to eastern redcedar in agricultural settings," Knezevic says. "The key for effectiveness of broadcast treatments is: 'the shorter the tree, the better the control.' Individual tree treatments can also be applied directly to the tree foliage or soil around the tree base. That kind of application can minimize the amount of herbicide used and exposure to non-target species."
Goats have proven to be an effective biological control for eastern redcedar on trees up to three or four feet tall.
"The goats should be part of an integrated control approach," Knezevic says. "Most eastern redcedar trees that are less than 24 inches tall can be killed in the first year by using goats in a paddock grazing system. On trees four to eight feet tall, control level is only about 50 percent. The goats will defoliate bottom branches and strip bark from the branches and trunk of taller trees. It could take five years of this kind of grazing to kill the larger trees."
Complete details of a UNL eastern redcedar research project is available at http://ianrpubs.unl.edu/live/ec186/build/ec186.pdf. Knezevic also posted a video on Youtube that outlines his recommendations for managing eastern redcedar at https://www.youtube.com/watch?v=t1cEXS3b2B4.
"The real key," Knezevic says, "is implement a program when the trees are small. That's going to result in the most effective management of the trees with the least amount of cost and effort."