Silvicultural Chemicals

6/9/2009 8:05:04 PM

Fertilization & Pesticides

Pesticides, including both herbicides and insecticides, are valuable tools in maintaining a healthy forest. The use of herbicides, rather than mechanical site-preparation methods, is recommended on erodible sites to protect water quality. Insecticides can be used to control certain insect infestations where outbreaks are localized, provided care is taken to minimize use in SMZs.

Fertilization may be used to enhance tree growth. Fertilizers can be applied safely with ground and air equipment, provided that care is taken and application is in accordance with label instructions and applicable state and federal laws. Research shows that little or no measurable increase in nitrogen and phosphorus occurs in streams following forest fertilization, provided care is taken not to apply the fertilizer directly on open water.

Proper planning, training and conscientious execution of the plan are keys to safe use of silvicultural chemicals.

Note: These guidelines are intended to complement state or local regulations relating to the sale, transportation and use of chemicals.

BMPs for Silvicultural Chemicals

  • Follow label directions and applicable state and federal laws in the storage, transportation, handling and application of all chemicals. All worker-protection standards should be strictly followed. All restricted-use pesticides shall be applied under the supervision of a certified pesticide applicator.
  • Know each chemical’s characteristics. Know also topography, soils, drainage, weather and other potential site hazards that might be important for preventing water pollution during application.
  • No leakage of chemicals should be permitted from equipment used for transporting, storing, mixing or applying chemicals.
  • Water for mixing with chemicals should be carried to the field in water-only tanks. The danger of getting a chemical into a ground or surface water supply must be avoided. An anti-siphon device is essential in the water intake to prevent backflow. Chemical mixing should only be done at the application site.
  • Mix chemicals and clean tanks only where possible spills will not enter streams, lakes or ponds. Do not mix chemicals or clean/flush tanks near wellheads.
  • Carefully plan ground and aerial application to avoid direct and indirect entry of chemicals into streams and impoundments. Special care should be taken when chemicals are used in the SMZ. Realize that significant portions of the SMZ will probably be left untreated. Leave well-marked buffer zones between target area and surface water.
  • Chemicals must not be applied when stream pollution is likely to occur through aerial drift.
  • Use spray equipment that is capable of immediate shutoff.
  • Where feasible, utilize injection or stump-treatment herbicide methods in areas immediately adjacent to open water.
  • If a spill should occur, construct a containment dike around it. Use absorbent material such as kitty litter, sawdust or soil to soak up fluid. Keep the spill from flowing into streams or bodies of water. Some spills will require notifying appropriate authorities.
  • All empty pesticide containers must be triple-rinsed and disposed of in accordance with label requirements.
  • The rinse water should be used in the pesticide mix and sprayed on the treatment area.
  • Clean equipment in a location where chemicals will not enter any stream, lake, pond.


  • Applying pesticides and fertilizers directly to water bodies such as streams, lakes or swamps unless specifically prescribed and approved for aquatic management.
  • Broadcast application of pesticides within SMZs.
  • Applying any herbicide adjacent to the SMZ that would damage trees in the SMZ or enter a stream.
  • Aerial chemical application during turns and over open water.
  • Exceeding intended or allowable dosages of chemicals.
  • Applying chemicals to vegetation protecting eroded slopes, gullies, drainages and other fragile areas subject to erosion.
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