August BMP Q&A

By: Chris Duncan, BMP Forester (Ret.), Texas Forest Service

Q:   I have a tract of timber which was clearcut last fall.  The logger who harvested the tract did a bang up job on installing necessary BMPs where they were needed.  My consulting forester has recommended that I conduct a site preparation burn later this summer to prepare the site for planting.  The tract has a stream on it that usually runs for about 3 months in a typical year.  Are there any special BMPs in regards to prescribed burning that should be implemented to ensure the water quality of the stream is not adversely affected?

A:   Glad to hear that you were happy with the job your logger did in implementing BMPs where they were needed.  Prescribed burning can be a beneficial management tool when used properly with trained personnel. Site preparation burns are often the hottest type burn and can remove a substantial amount of the surface organic material. This type of burn would have the greatest potential for increased surface runoff or soil erosion, particularly on steeper slopes.  Use the following guidelines to help reduce the risks to water quality and soil erosion on your tract.

Site preparation burning creates the potential for soil movement.  A significant amount of soil movement can be caused by the preparation for the burns, i.e., firebreaks. Firebreaks should have water control structures that divert runoff away from water bodies in order to minimize erosion.  Site prep burns on steep slopes or highly erodible soils should only be conducted when they are absolutely necessary and should be as "cold" as possible.  Stabilize and revegetate firelines, if needed, on grades in excess of 5% or areas subject to accelerated erosion or known sensitive areas.

Firelines should be constructed on the perimeter of the burn area and along the boundary of the Streamside Management Zone (SMZ). The purpose of protecting the SMZ from fire is to safeguard the filtering effects of the litter and organic matter.  All efforts should be made to minimize the impact from site-prep burning within an SMZ.  Firelines should follow the guidelines established for logging trails and skid trails with respect to waterbars and wing ditches, and should be only as wide and as deep as needed to permit safe site preparation burns.  Firelines which may cross a drainage should be turned parallel to the stream or have a wing ditch or other structure allowing runoff in the line to be dispersed rather than channeled directly into the stream.

Finally, make plans to maintain your firelanes after the burn has been completed.  Firelanes on highly erodible sites or other problem areas should be inspected periodically to correct erosion problems by installing dips, wing ditches, waterbars, etc. and/or by seeding.  Mowing, rather than blading, should be used to maintain firelanes in order to avoid exposing mineral soil to potential erosion.

For more information on forest road BMPs and other BMPs visit the Texas Forest Service webpage at http://texasforestservice.tamu.edu/water, contact me at (903) 297-3910.

* This article was published in the August 2010 issue of the Texas Logger