After the Fire - Hand Raking
Hand raking can also be accomplished with light equipment such as an all-terrain vehicle (ATV) pulling a harrow where there is sufficient access for the equipment and slopes are less than 20 percent.
When is hand raking used?
Hand Raking or light scarification is used on severely burned slopes with hydrophobic soil properties that will also be treated by mulching for erosion control and may also include seeding to reestablish vegetation. It is primarily applicable to areas that are too small for efficient use of large machines or are not accessible by machines due to slope steepness or presence of obstructions. The soil must be loose to begin with such that it can be tilled with hand tools or a light harrow.
The primary use of this practice is to improve seedbed conditions immediately ahead of a seeding operation.
Hand raking does not till the soil deep enough to have any appreciable effect on infiltration of or reducing runoff. In cases where the fire has induced hydrophobic characteristics that exist only at or near the ground surface hand raking may have some benefit to reduce the hydrophobic effect by mixing affected soil with unaffected soil from deeper in the profile.
Hand raking increases the erodibility of the soil so it must be used in combination with erosion control treatments, such as mulching.
How is hand raking performed?
Laborers outfitted with rakes, hoes, Pulaskis, or other rugged hand tools, and appropriate personal protective equipment, loosen and mix the soil to a depth of 2 to 4 inches over the areas to be treated. On slopes of less than 20% with few obstructions light scarification can be accomplished with an ATV pulling a tined harrow.
The entire slope may be raked to achieve the maximum effect. To reduce treatment costs on large areas hand raking can be accomplished in 8-foot-wide strips spaced uniformly over the slope. A contour line is marked about 1/3 the way down the slope to establish a key line. The strips are marked and raked parallel to this key line. The maximum recommended spacing between strips is shown in the following table:
Maximum Recommended Spacing
- Slope gradient less than 5 percent - Raked strip spacing 160 feet
- Slope gradient 5 to 10 percent - Raked strip spacing 120 feet
- Slope gradient 10 to 20 percent - Raked strip spacing 60 feet
- Slope gradient 20 to 30 percent - Raked strip spacing 30 feet
"CAUTION: After a fire, many trees are weakened from burning around the base of the trunk. These trees can fall over or blow down without warning. Shallow-rooted trees can also fall. Therefore, be extremely alert around burned trees.