Exotic Species Control

The Belwin Conservancy maintains a philosophy of restoring native vegetation patterns on its property. Restoration techniques include removing non-native species, planting native ones and maintaining the restored vegetation with cutting and burning. Restoring native species not only increases plant diversity but also supports far more wildlife than aggressive non-native species.

The removal efforts include:

  • European buckthorn, which was originally sold as a hedge but has gone wild and is choking out native species throughout wooded areas.
  • Prickly ash, which was promoted by the soil conservation service as a way to quickly grow cover for highly eroded areas but does not stop until it chokes everything out with an impenetrable wall of thorns.
  • Locust, which also is good for healing highly eroded areas but does not allow diverse species of vegetation to co-exist where it grows.
  • Red oaks in areas originally harboring stately bur oak trees in oak savannas.
  • Amur maples, which provide stunning fall colors, but tend to overtake all other vegetation and choke it out.
  • Thistles and spotted knapweed which are not conducive to native habitat.

The Belwin Conservancy uses a number of methods to remove these species. As its landholdings have increased, it has become increasingly difficult to keep up with efforts to clear areas of non-native vegetation. As a result, the Belwin Conservancy has invested in mechanical equipment that can aggressively remove large areas of non-native vegetation. It also utilizes specific herbicides by applying it to stumps of these species to kill the root systems. Once an area is cleared, the Belwin Conservancy either mechanically maintains an area with brush cutters, planting of native species or through the more natural method of setting controlled fires to kill resprouting of these species from roots or seeds.


Buckthorn was imported to this country as a hedge from Europe. Unfortunately, when not cut back into a compact hedge, it produces vast quantities of seeds that, while not very nutritious, are tasty to birds and therefore becomes widely spread by them. It then takes over a wooded area choking out other vegetation and creating a dense wall of vegetation. The plant is identifiable in the late fall as it is usually the last bush to loose its green leaves, has black berries, and if cut will show a reddish wood.

While the woods owned by the Belwin Conservancy were once tree covered but open, they have become full of buckthorn. This competes with other native vegetation that would support a greater variety of animals.

The Belwin Conservancy recognized this problem over 20 years ago and has employed numerous strategies to control and remove it. Unfortunately, when the buckthorn is cut, it resprouts aggressively. A sufficiently hot fire will stunt or even kill it but this process can take years and requires a regular regime of burning to be effective. Cutting or burning takes seven years for the bush to produce seeds so the process curtails the production of additional seeds.

The Belwin Conservancy has found regular prescribed burning also encourages the production of grasses. More abundant grasses will increase the heat of the fire and do a more effective job of killing the buckthorn. However, once this routine is stopped, the buckthorn will begin to invade again. The Belwin Conservancy attempts to burn its controlled area on a three year cycle.

The best strategy to remove buckthorn is to pull it out by its roots. Unfortunately, this is not a viable alternative when looking at managing hundreds of acres since when it gains a hold, there can be multiple sprouts per square foot.

The one remaining strategy is to use herbicides in conjunction with other strategies to reduce the resprouting and subsequent seed production. The Belwin Conservancy has used both Roundup and Garlon and both are effective. The most effective technique is to treat the woody stem or the stump, which causes the herbicide to be pulled into the root system where it kills the plant. Both of these herbicides are relatively short lived.

Prickly Ash

Prickly ash is a native tree from the southern part of the United States. Because it is fast growing, it was used and recommended by the Soil Conservation Service for many years when confronted with situations of excessive erosion to quickly stem the problem. It reproduces both by seeds and through its root systems sending up sprouts wherever its roots reach.

Unfortunately it is very successful. It quickly chokes all other vegetation off and becomes the dominant species. It is named appropriately as it has nasty thorns that make areas where it grow extremely difficult to use and enjoy. It spreads rapidly and grows quickly. When cut, it regenerates and may grow four – six inches in a single season.

Continued mechanical cutting does keep Prickly Ash from becoming a forest and with enough time appears to stunt and even kill it although this process requires a focused commitment for many years. Belwin has used this strategy in some areas.

The Belwin Conservancy has found when there is a new "outbreak or infestation" of prickly ash, the best strategy is to apply Garlon to the base of the standing tree on the bark or on the stump of a newly cut tree and kill the tree so the area won't require cutting every year. Smaller pockets of prickly ash can successfully be treated in a single growing season.