The best way to prevent eastern red cedar trees from overpopulating pastures is by cutting them down or applying herbicides.
The cedars can compete with grasses for water and nutrients, light, reduce forage production, and interfere with cattle handling. If a pasture is too infested with cedars, it can reduce the grassland rental or sale prices.
There has been several research trials done on the effectiveness of manual, prescribed burning, biological, and chemical management control of red cedars. They have discovered that the biggest factor for herbicide efficiency and protecting producers bottom lines is the tree’s height. 
This research conducted by the Institute of Agriculture and Natural Resources could help producers control cedar tree populations, which may be on the the increase because of the decline use of prescribed burnings to eliminate trees. Since the frequency of wildfires has increased, fire officials have decreased the number of burn permits issued every year.
Landowners have also started to create windbreaks with red cedar seedlings. Since birds eat the bluish, berry-like fruits that these trees produce, the seeds get spread in their dropping and new seedlings sprout where they don’t belong. There has been research done on red cedars that say one day they could clone these trees so that they would only produce male trees which would prevent reproduction.
Farmers and ranchers should take action to prevent the spreading of cedars as soon as they see them. On average, red cedars can grow up to a foot every year, so it is very important to control them while they are small.
To control cedars in pastures that have many short trees, (less than 2 feet tall), you should use herbicides such as Tordon 22K, Grazon P+D, and Surmount. If you are trying to treat an individual tree that is up to 6 ft tall, these herbicides work too. However, the most economical option for trees up to 6 ft tall is cutting them down.
For less severe infestations of trees that are up to 2ft tall, you can pull or dig them up. Producers can also mow the trees that are less than 2ft tall with mower blades that are set close to the soil surface or below the tree’s lowest branches. This can be done shortly after haying.
An inexpensive way to eliminate small red cedars and other noxious weeds is the use of periodic prescribed burns. Also, by placing goats in pasture with cattle, you will be able to eliminate the small trees. Goats like to eat cedars and noxious weeds, but will not complete with your cattle for the grasses.
To prevent the tree population from spreading, producers can cut down the female trees or berry-producing trees.
In order to prevent future problems with red cedars, producers should scout there pastures annually to control the growth of the small cedars and use the method that is appropriate to their situation.