Prescribed Fire Challenges
Despite the challenges of a prescribed burn, a properly planned and executed prescribed burns should not cause adverse effects to health and human welfare, our water supply, or the air we breathe.
Effects on Human Health and Welfare
The general public’s occasional and brief exposure to low concentrations of drift smoke is more of a temporary inconvenience than a health problem. However, smoke can have negative short-and long-term health effects such as eye and respiratory system irritation. Most particulate emissions from prescribed fires are small enough to enter the respiratory system. It is possible that lengthy exposure to relatively low concentrations of smoke over many years can contribute to respiratory and other health problems.
High concentrations of smoke near homes of people with respiratory illnesses or near health-care facilities also can be problematic. As can burning noxious plants such as poison ivy in the smoke—possibly causing skin rashes and respiratory system irritations.
Effects on Water
The main effect of prescribed burning on the water resource is the potential for increased rainfall runoff. When surface runoff increases after burning, it may carry suspended soil particles, dissolved inorganic nutrients, and other materials into adjacent streams and lakes reducing water quality. Rainwater leaches minerals out of the ash and into the soil. In sandy soils, leaching may also move minerals through the soil layer into the groundwater. Generally, a properly planned prescribed burn will not adversely affect either the quality of ground or surface water in the South.
Effects on Air & Smoke Management
Prescribed burning helps achieve many objectives but it also can pollute the air. Smoke from prescribed burning is one of the greatest single factors causing public concern. The amount of smoke emitted and its dispersal are affected by how and when the burn is conducted. There are ways to monitor and lessen the impact of smoke from prescribed burns.
Most southern states have either voluntary or mandatory smoke management guidelines for planning a prescribed burn. Your local state forestry office can advise you of recommended and required procedures. Many states also conduct smoke management workshops for prescribed burners.
There are a few ways to calculate the atmosphere’s capacity to disperse smoke—called ventilation rate or ventilation factor. They all include the following steps:
- Plot direction of the smoke plume
- Identify smoke-sensitive areas
- Identify critical smoke-sensitive areas
- Determine fuel type
- Minimize risk
