Kiap-TU-Wish

 

Brushing Research

The Kiap-TU-Wish Chapter of Trout Unlimited carries out a brushing project on the upper Kinnickinnic River most winters. Brushing as a habitat improvement project is based on research by the Wisconsin Department of Natural Resources. In the DNR Technical Bulletin Number 115, Dr. Robert Hunt of the DNR points out that “the best stocks of trout (in abundance and growth rate) tend to be found in meadow-type reaches”. He also points out that White and Brynildson, in DNR Technical Bulletin Number 39, advocated establishment and maintenance of a “sturdy turf” of grasses, broad-leafed annuals and low shrubs through use of such techniques as controlled burning, periodic mechanical brush cutting, application of selective herbicides, seeding and fencing to exclude livestock. They advocated the radical concept that planting trees beside trout streams should be actively discouraged in Wisconsin except where there is reasonable evidence that summer temperatures for trout would be improved by doing so.

Dr. Hunt goes on to outline the benefits of brushing:

“If increased solar heat does not produce deleteriously high water temperatures, reduction of woody shade canopy could have several beneficial consequences for trout and the sport fishery they sustain:

  • Creation of more desirable habitat for trout as a result of greater growth of aquatic macrophytes which both provide shelter for trout directly and constrict flow to increase scouring, deepening of pools and undercutting of banks.
  • Firmer stream banks consisting of grassy turf less susceptible to erosion; a gradual narrowing of the stream channel and accentuation of channel sinuosity rather than the widening and straightening process associated with tree-lined reaches, particularly reaches dominated by speckled alder (alnus rugosa).
  • Increased production of aquatic invertebrates used as food by trout due to increased abundance of aquatic plants that provide aquatic invertebrates with both substrate and their source of food, either directly or indirectly.
  • An increase in terrestrial invertebrates accidentally entering the stream and available as food for trout, particularly during the summer months when physiological conditions are good for trout growth but abundance of aquatic invertebrates is often declining.
  • Improved growth of trout as a result of increased availability of food and an improved temperature regime for growth.
  • Easier season-long fishing conditions, more hours of angling recreation and greater harvest of presently underutilized trout stocks in small streams.”

The Wisconsin Department of Natural Resources has carried out research to scientifically validate this management technique. One such study was carried out on the Kinnickinnic River in 1972 through 1977. Abundance of trout increased in 3 of 5 treatment zones along with an increase in legal sized and quality-sized fish (10 inches or larger) in all 5 zones. A summary of this study can be found along with other brushing studies in DNR Technical bulletin Number 162.

  • Guidelines For Management of Trout Stream Habitat in Wisconsin, Wisconsin Department of Natural Resources, Technical bulletin No. 39, 1967, reprinted 1986.
  • Removal of Woody Stream bank Vegetation to Improve Trout Habitat, Wisconsin Department of Natural Resources, Technical bulletin No. 115, 1979.
  • A Compendium of 45 Trout Stream Habitat Development Evaluations in Wisconsin during 1953 -1985, Wisconsin Department of Natural Resources, Technical bulletin No. 162, 1988.

Wisconsin Department of Natural Resources Technical Bulletins can be obtained free of charge by writing to:

WDNR
Bureau of Research
Box 7921
Madison, WI 53707