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Cross Timbers

Tree Model

Fire Behavior in Wooded Areas

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Fuel

Both the living and dead vegetation that can potentially burn in a fire.
Fuel refers to such items as downed dead woody material in various size classes, herbaceous vegetation, live foliage, etc.

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Background - Temperate Forests

Four Layers

Canopy
Understory
Shrub
Surface/Floor

FLOOR

SHRUB

UNDERSTORY

CANOPY

(Tree Crowns)

To investigate how fuel distribution can influence fire behavior, understanding plant community stratification is important. Be aware that the information on this slide corresponds to Table 1 on the student worksheet. Temperate forests, like the Cross Timbers, can be separated into four layers. The canopy, or the crowns of trees, is the top layer of woody species consisting of overlapping leaves and branches. The understory is confined by the first branches of dominant/mature trees and the top of the shrub layer. The shrub layer is made up of woody, perennial plants that usually have many stems and that are shorter in stature than trees. The lowest layer is the floor which is dominated by herbaceous vegetation, such as grasses and wildflowers, that does not produce persistent woody tissue like trees and shrubs. While viewing the following images, keep these four layers in mind. Click

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Fuel

Tree Model Fuel Types

Surface Fuels
Debris
Ladder Fuels

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Fuel

Surface Fuels are made up of a wide variety of living and dead vegetative material found on the surface of the ground.

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Fuel

Debris, for this activity, is made up of dead branches or trees found on the ground.

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Fuel

Ladder Fuels are vines, shrubs, and young trees that allow fire to move from the surface/floor into the canopy or crowns of dominant trees.

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Cross Timbers Tree Model

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Cross Timbers Tree Model