Fire Safety at the Wildland/Urban Interface
Use Fire-Resistant Plants
No plant is fire proof, but some plants are less flammable than others. If you must use really flammable plantings in your landscape, plant them farther from the house, don’t group or isolate them from fire by using hardscapes.
There are lists of plants assorted by their flammability. Some of this knowledge is amassed by experience and common sense, but a good deal of Cooperative-Extension-based research has gone into determining the flammability of certain plants. At the end of this chapter there is a large list of plants; however, no list can hope to keep ahead of the number of plants available or newly introduced into the nursery trade. When you are going to select a plant for your landscape, remember what you know about fuels and fire behavior from the beginning part of this chapter,and try to evaluate a plant selection based on what you know about flammability. The things that influence a plant’s flammability are:
• Moisture content
• Leaf and twig shape
• Presence of oils or resins
• Branching pattern
• Deciduous or evergreen
• Moisture Content
The moisture content of the leaves and plant have a considerable influence on the ability of a fire to ignite the fuel in the plant. The more moisture in the plant, the more energy must be expended to drive off the moisture before the leaves can ignite. This moisture is dependent on the nature of the plant to a certain extent. Succulents have more moisture in their leaves than grasses or pines.
Equally important, however, is the moisture that has been available to the plant in the recent past. Fire seasons are fire seasons because the fuel that is available is dryer. Fire season is usually one of the drier seasons of the year when most plant moisture is below ground. Any season can be drier than normal, however. After an extended drought, even leafed-out deciduous trees in summer can be as dry as they are in winter. This is one reason to be aware of your surroundings when you live at the Wildland/Urban Interface. Choosing plants that are less prone to drought stress is one approach, while another is to minimize the use of plants that are prone to dryness, or even to eliminate them from the Defensible Space of your landscape altogether. Masses of dried warm season grasses are stunning in the landscape and very important areas for wildlife; however, they shouldn’t be the main planting on that steep slope up to your deck, or allowed to run as a meadow within your Defensible Space perimeter.
• Leaf and Twig Shape
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