The enemy

Western juniper (Juniperous occidentalis) is a native perennial tree that grows everywhere from our desert to the subalpine areas high in the mountains. Junipers offer great forage and habitat for deer and other wildlife, but like other plants can become an invasive weed. In fact, the latest figure had close to 9 millions acres of this tree being established as a weed (an unwanted plant) in Southwest Idaho, Oregon and Nevada. This evergreen tree usually forms small cone berries for seeds that can remain viable for many years. Recent population increases are contributed to fire suppression, overgrazing and recent climate changes.

Junipers can become monocultures, crowding out desirable forbs and grasses, making the areas useless to numerous wildlife species. The berries are desirable for some birds and mammals for food, thus they spread the plant everywhere. Stands of trees have been known to dry up perennial streams. The trees, like many of the others in the cedar family (like the noxious weed salt cedar) release a compound that prevents other species from growing underneath them, thus reducing quality habitat for species variability.

The defense

Juniper trees can grow for very long times — as many as 1,500 years. But, due to their abundant seed source, they have the ability to spread fast. Selective cutting is very effect and allows the crew to prescribe burn the downed trees later in the winter to remove the chance of fire. One herbicide that is effective against the juniper is Spike 20P. This pellet can be hand-tossed under the canopy of the tree and that tree will be terminated, yet allow the rangeland grasses and forbs to continue growing. Other products are effective as foliar treatments and need to be applied when the tree is actively growing (new bright green/yellow growth). As with all weed programs a long-term management program needs to be in place before a massive tree cutting program is started and lets not forget that this is a great tree for wildlife.

Call your local weed professional for help with this and all weeds and there are many programs available to help land managers reduce the impact of this native plant.