Wildfires


September 11, 2001

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Techniques used to stabilize the soil and rehabilitate the land

Contour-felled logsContour-Felled Logs
Burned trees are cut down and logs are laid horizontally across the hillside. Most of the logs are 8-14 inches in diameter and held in place by wooden stakes. A small trench may also be dug on the uphill side of the log to collect water and store sediment.

Hand Trenches
In the same area as the contour-felled logs, crews used hand tools to dig more small trenches uphill from the logs. These horizontal trenches also caught water and dirt as it flowed down the hill.

Contour TrenchesContour Trenches
A mini-excavator is used to dig larger horizontal trenches along the hillside. These trenches are usually 2-3 feet wide and 2-3 feet deep. Every 30-50 feet, dirt is piled into the trenches to create a dike. If a trench breaks, the water and soil would stop at the dike and not continue down the hill.

 

Straw WattlesStraw Wattles

Wattles are made of straw wrapped in a mesh that will break down in sunlight. They are about 8 inches in diameter, 25 feet long and weigh about 35 pounds and placed horizontally across the hill. Stakes hold them in place. Wattles slow the water and soil moving down the hill and provide a good seed bed for future seedlings.

Tilling
From time to time horizontal strips of earth will be tilled 6-12 inches deep to allow water running down the hill to soak into the ground. This also provides a good seed bed. Bands of undisturbed earth are left between the tilled rows allowing plants surviving the fire to resprout.

Straw damsStraw-Bale Check Dams
Dams made of three or more straw bales are built across gullies to slow water and soil as they wash downhill. The straw bales are wrapped in wire mesh to help hold them together. Then they are covered with a strong cloth. The straw and cloth are porous allowing water to seep through but collects the sediment behind the dam. There are usually 3-8 dams per gully. As the water runs down the hill, its velocity is slowed as it is routed from basin to basin behind each dam.

Sediment Ponds and Basins

Ponds and basins are built in gentle stream channels or at the base of hills to trap and store water running downhill. As the water sits in the pond, it soaks into the ground while providing a water supply to wildlife in the area.

Seeding A rangeland drill pulled by a tractor is used to seed many burned areas. Round disks cut furrows into the ground and seeds are dropped from long tubes behind the discs. Chains dragging behind the tractor help cover the seeds with soil so they sprout.

Aerial seedingSome seed, such as sagebrush seed, is aerially seeded from a bucket carried below a helicopter. It is usually dropped onto snow-covered ground to the seed will stay moist and will sink into the ground as the snow melts.

Some seeding is sometimes done by volunteers using hand-held spreaders. They are followed by other volunteers who raked the seed into the ground.

 

Permission granted to use this material for educational purposes only. The photographic images were provided by the Bureau of Land Management
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