Control measures should be initiated as soon as possible, both to improve effectiveness and reduce total costs. In most cases, a single control measure can't provide long term management of this species. However, if the control practices are integrated in a systematic manner, significant advances can be achieved. Methods of control must be based on an integrated management approach, which includes a combination of manual, mechanical, cultural, biological and chemical control methods.

Manual control involves pulling or digging trees. It can be very effective for small areas and is most efficient on trees up to 2 feet tall. Mechanical control methods such as cutting or mowing involve use of various hand held or motor-powered tools. Mowing of short trees can be also utilized as part of the regular cutting and haying process. The overall key to success in cutting or mowing is to cut the tree at the soil surface or below the lowest branches. Red cedar trees that are cut low should not regrow. In addition, if the goal is to just reduce overall number of trees and reduce further spreading (eg. management of wildlife habitat), it is recommended to cut only female trees (the trees that produce berry-like fruits).

Biological weed control or bio-control is the use of natural enemies to reduce weed populations to economically acceptable levels. In the case of red cedar control, goats can be utilized as an effective bio-control agents for trees that are up to 3ft tall. Goats are known browsers, whose diet consists 75% of non-grassy species, which means they will not compete with your cattle for grass. They are also alternative tool for control of many noxious weeds, especially for leafy spurge. Keeping several goats at your pasture can help control many non-grassy species including red cedar trees.

Prescribed fire can be also used. This method is inexpensive and effective against smaller trees. However, its effectiveness declines as tree size increases. Adequate fine fuel (usually, last year's dead grass) is necessary for satisfactory results. Safety also is a concern since many managers lack experience with fire and the equipment required to conduct fires.

Chemical control should be also considered. Herbicides should be viewed as just another tool in the integrated approach tool box. Herbicides can be used for both ‘individual-tree' spraying and broadcast application.

Individual tree treatments: Currently there are several herbicides suggested for individual tree treatments in Spring or Fall. Examples include Tordon 22K, Velpar-L and Spike 20P. Tordon 22K can be used as a spot gun application of soil around the tree before rainfall. Rainfall will help uptake the chemical. The recommended rate is about 1 cc's (ml) per foot of tree height. Cost of Tordon 22K is about $85 per gallon. It would costs about $65 per acre plus labor ($15 /hour) to spray 1500 trees that are about 2 feet tall. Velpar-L can be also used through a spot gun in Spring at the rate of 4 cc's (ml) per every inch of tree diameter. Cost of Velpar is about $65 per gallon. Spike 20P is another alternative but only in non-crop areas as a total vegetation control at the rate of 0.5 oz per every inch of stem diameter. Cost of Spike 20P is about $9 per pound of product.

We have also conducted a preliminary study of individual tree treatments at two locations (Center and St. James) in northeastern Nebraska. Excellent tree control (>90%) was achieved with Plenum (sold as “Surmount”) at 1.5 % volume per volume (v/v), Grazon P+D at 2.0% (v/v) and Tordon 22K at 1.0% v/v (Table 1). All other treatments provided poor control (<50%). Grass injury in the form of temporary yellowing and burning of top growth was evident among all treatments especially for Tordon 22K (Table1). Cost of Grazon P+D and Tordon 22 K ranged from $11-$16 per acre (Table 1). Plenum and Garlon are experimental products, therefore they are not available for purchase.

Here are a few practical hints: (1) To help you determine volume per volume basis, for example the 1% v/v equals 1 gallon of product per 100 gallon of water for large tanks. For smaller back pack sprayers use an equivalent of 1.3 oz of product per every gallon of water. (2) Apply about 1.5 oz of the above prepared spray solution per every foot of tree height. Walk around the tree and just spray enough to get a glisten (shine) on the leaf surface. Solution dripping off the tree indicates a rate that is too high and a waste of time and money. (3) As an example, we calculated that 1 gallon of spray solution should cover 15 individual trees that are 6 feet tall at 20 PSI and nozzles XR8002.

Table 1: Percent red cedar control and grass injury at 100 days after treatment in individual-tree study at two locations (Center and St. James).

Broadcast treatments: In general the taller the trees the poorer the control. Excellent control (>90%) of up to 1 foot tall trees was achieved with Plenum (5pts), Grazon P+D (6pt & 8pt) and Tordon 22K (2pts) at both locations (Table 2). Same treatments, however, provided poor control (<50%) of taller trees (>2 feet). Plenum at 4 and 5 pts/acre provided good to excellent control of up to 2 ft tall trees. All other treatments provided poor control (<50%) regardless of the tree height (Table 2). Physical removal treatment (#10), provided best control (100%), however it was the most expensive method.

Cost of Grazon P+D and Tordon 22 K ranged from $21-$26 per acre. Plenum and Garlon are experimental products and can not be purchased. Cost of physical removal treatment was about $120 per acre. It was based on a calculation assuming that $8 hours of work was needed to cut 1500 trees, 2 feet tall, per one acre and an hourly labor cost of $15. For illustration purposes, 1500 trees per acre are equivalent of 1 tree per 3 square yard. Grass injury in the form of temporary yellowing and burning of top growth was evident among all treatments.

Table 2: Percent control of eastern red cedar at two locations (Center and St. James) as influenced by the tree height in broadcast study at 100 DAT.

What to do with “standing dead-trees”: Commonly asked question is: What to do with the trees that died as the result of herbicide application. This is especially true for taller trees (> 4ft). Of course they can be removed within the same season. However, if that was the original intension, the chemicals should have not been used. Do yourself a favor, save some money. Just cut the trees at the ground level. They will not re-grow, however watch for stumps, they can puncture vehicle tires.

Standing dead trees will reduce the aesthetic value of the land, however there are several benefits of leaving dead trees stand for several years: (a) they will protect the grass to regrow and re-establish on those individual spots, (b) help against soil erosion and (c) protect against wind or snow. Trees that are 4-8 feet do not have much of the red heartwood tissue so they will naturally detterriate within 3-6 years. (SK)