Choosing the Right Plants - University of Nevada, Reno

4 • UNIVERSITY OF NEVADA COOPERATIVE EXTENSION^

CHOOSING THE RIGHT PLANTS FOR NORTHERN NEVADA’S HIGH FIRE HAZARD AREAS

COMPONENTS LOWER FIRE HAZARD HIGHER FIRE HAZARD

FUEL

Fuel Load Small amounts of fuel present Large amounts of fuel present

Size and Shape Large size fuels (greater than 3 inches in

diameter)

Small size fuels (1/2 inch or smaller in

diameter)

Moisture Content High moisture content, such as healthy,

actively growing flowers and lawn

Low moisture content, such as dead branches

and dried grass

Vertical Arrangement Ladder fuels absent Ladder fuels present

Horizontal Continuity Patchy and widely spaced fuels Dense fuels, growing close together and con-

tinuously

Compactness Low-growing, dense and compact fuels Open, upright and loosely arranged fuels

Chemical Content Fuels consist of plants without shiny, waxy,

oily or resinous leaves, twigs, and branches

Fuels consist of plants with shiny, waxy, oily,

resinous leaves, twigs, and branches

WEATHER

Wind No wind High winds

Relative Humidity High humidity Low humidity

Precipitation We t Dry

Temperature Low temperature High temperature

TOPOGRAPHY

Steepness of Slope Flat, level terrain Steep, sloping terrain

Slope Position Base of slope Upper reaches of slope

Aspect North-facing slopes South- and southwest-facing slopes

Topographic Feature Open area Box canyons, narrow canyons, ridge tops

Attributes of low and high fire hazard environments

The wildfire threat is not the same to every home, but varies according to the characteristics of the fuel,

weather, and topography. These three components of the fire environment determine the ease of fire ignition, speed and

direction a fire will travel, and the intensity at which a fire will burn. A home located at the top of a steep, south-facing slope

that is covered with dense sagebrush and dried grass on a dry, hot, windy day constitutes a high fire hazard. On the other hand,

a home located on flat terrain, surrounded by a well-maintained and irrigated landscape on a cool, calm, humid day represents

a much lower degree of wildfire threat. Since weather and topography cannot be altered, the only opportunity to reduce the

fire hazard lies in changing the characteristics of the fuel. Wildfire fuels include naturally occurring plants such as sagebrush,

ornamental plants in the residential landscape, and wood building materials.