Drought and fire protection landscape recommendations

14 May, 2009 By: Landscape Management Staff LDB Solutions

Fire poses an even greater threat in many areas experiencing extreme drought conditions. Dry trees, grass and shrubs are more apt to catch fire quickly, and they also increase the speed and intensity of a fire, making it harder to control and contain. Drought will also impact local water sources such as lakes and rivers, reducing the sources of available water that can be used to put out fires.

This map shows locations that experienced wildlfires greater than 250 acres, from 1980 to 2003. Sources: Bureau of Land Management, U.S. Forest Service, U.S. Fish and Wildlife Service, Bureau of Indian Affairs, National Park Service, and the USGS National Atlas.

Many homes have been built in natural fire zones. The California Landscape Contractors Association (CLCA) offers the following recommendations to help you protect your clients’ property during fire season.

1. Create a defensible space. Remove all dead plants, trees and shrubs. Keep your clients’ lawns well mowed and healthy, and all plants pruned and well maintained. In dry conditions, increase the recommended defensible space around your clients’ homes from 30 to 50 ft. or as recommended by your local fire department, especially if your area is prone to wildfires.

2. Include 100 to 150 ft. around a home in any fire management plan. Thin trees and brush within this space and eliminate flammable grasses and plants growing under trees. As conditions get drier and hotter, the speed of fires will increase. Allowing a larger defensible space gives your clients more time to get out safely and the fire department more time to save the home.

3. Space trees at least 30 ft. apart and prune lower limbs to a height of at least 10 ft. Make sure there are no branches that hang over structures, which could allow flames to jump to the home. Highly flammable trees, such as eucalyptus and pine, should be avoided or removed if located close to structures.

4. Contact your local fire department or click here for a list of high-fuel plants that should be removed. If you are in a high fire danger area, fire agencies will often send an inspector at your request to help determine plants and trees that pose a threat to structures.

5. Use fire-resistant plants and do not plant in large masses. This helps prevent the fire from having the continuous fuel needed to carry the fire to the home. Use decorative rock, gravel, stepping stones, cement or stone garden art, stone walls, or other items close to homes, which can help modify, slow or break the path of a fire. Your local fire department or nursery will have a list of fire-resistant plants native to your area.

6. Due to reduced water allocations in some areas, it may not be possible to keep a well-watered landscape or to use supplemental irrigation. Consider using fire-resistant plants that are also drought tolerant, along with water-saving irrigation technology or a drip system that could help maximize your clients’ water allowance.

7. Plant beds should be filled with low flammable plants or decorative rock. All flowerbeds should be mulched. Mulch helps keep water in the soil and helps keep plants healthy. Be careful not to use pine bark, thick layers of pine needles, or other flammable mulches.

8. Make sure water sources needed to fight the fire are working and easy to find. Plastic irrigation lines and parts are flammable, and should be installed underground. Also consider some type of rain harvesting or other water storage system.

9. Consider entrances and exits as defensible space. If they are lined with trees or other burning materials, your clients may not be able to escape and/or the fire department may not be able to access the property.

Preventing soil erosion after a fire

When protective plants are removed, soil becomes vulnerable to erosion. Soil erosion can happen slowly or it can happen very quickly in a heavy rain. Defensive measures need to be taken immediately to prevent the soil from blowing away, washing away or collapsing into a mudslide. The exact measures needed for your clients’ property are based on the soil type, slope grade, home location, weather, water availability, etc.

In the case of wind erosion on flat ground, putting something over an area of flat soil to keep it from blowing away is effective until plant life resumes. In some areas tackified straw pellets, mulch or other erosion control materials may need to be applied.

The steeper the slope, the harder it is to successfully introduce plants and other items that will keep the ground from eroding. Erosion control blankets, straw wattles, hydraulic mulch and other erosion control materials can be used to help hold slopes in place. Depending upon the slope, retaining walls, interlocking concrete blocks or terraces may be necessary. Consider temporary erosion control measures to keep the ground from washing away until the plants recover. Native plants in burned areas will return on their own.

Water flow is an important factor of any erosion plan. Never underestimate the power of storm water and debris. Evaluating the area and planning for storm events is a critical first step to protecting the property.