Brush Control

Knowledge Nuggets

• Livestock grazing of woody species is an inexpensive and effective brush management tool when understood and managed accordingly.

• During the first half of the growing season, cattle graze aspen poplar, wild rose, wild raspberry, wild gooseberry, saskatoon, choke cherry, and pin cherry as a small part of their diet. Carefully planned and executed rotational grazing systems can sustain this grass-woody plant forage resource for many years.

• Prescribed burning is an inexpensive and effective method of managing brush when combined with appropriate grazing practices. The problem with prescribed fire is the risk of escape due to abnormal weather events or an inexperienced crew, as well as unfavorable government policies.

• A single prescribed burn can top-kill an aspen forest. Subsequent short duration, high intensity grazing can be used to manage young woody sprouts as forage. It also enables grasses and broad-leaved herbs to establish. The shrub-grassland that soon develops produces five to ten times more forage than the original aspen forest.

• Silverberry (wolf willow) is a "good" shrub that fixes nitrogen in the soil and allows enough light through the canopy to permit grass growth. The woody stems act as a partial barrier to grazing enabling greater grass productivity and plant diversity under the shrubs than in open grassland.

• Western snowberry (buckbrush) is a tough shrub that out-competes grasses for light, grows in thick clumps, and is unpalatable to cattle for most of the year. A mid-August mowing causing fall frost damage to the young re-sprouts, followed the next spring by a herbicide application will kill snowberry stems enabling the production of more forages.

• A single brush control treatment is usually effective for only a few years. Piece-meal applications are not recommended regardless of whether it is bulldozing, cutting, mowing, disking, burning, or herbicides. Rather a brush management program that includes repeated treatments and is included within a forage production and grazing plan will yield more success in managing brush and providing forage for grazing animals and wildlife.

• Some brush cover is recommended for all grazing lands in the aspen parkland. Brush traps snow in winter, provides shelter for livestock, and habitat for nesting and feeding birds and other wildlife.

• Aspen is now a commercially important tree in the boreal forest. Clear-cut logging of commercial aspen stands is followed by a prolific growth of young aspen sprouts. In spring and early summer only light grazing can be tolerated by the current annual growth of these young aspen suckers because the stems are so tender and cattle prefer them as forage.

• In spring, new growth of aspen can be easily sheared by cattle but by August the young aspen stems have hardened so much that cattle can rarely break them. In late summer the cattle strip and eat the leaves. Thus, by August moderate levels of cattle grazing can be tolerated in newly establishing aspen stands.