Trees for Soil Erosion Control

By Liliana Usvat

Grow more trees. This seems to be the best way there is to prevent the soils being washed away. Trees, especially those with big, sturdy roots, can hold the soils intact. Growing a line of trees around a farm, if possible, can be a good idea for preventing most mechanical methods of erosion.

• A lot of afforestation (also known as reforestation) activities are being managed on a global scale to preserve the soils.
• A special modification of this is the riparian vegetation that is grown at the interface of any land and water line. The intention is to prevent the soils from migrating into the water line, or to prevent the water from seeping onto the land and carrying the soils away with it.

  (willows tree)

Willows will root in the most barren and unstable of soils, which makes them the most valuable tree for erosion control.

The cuttings should be at least 18 inches long and at least a half-inch thick to create new trees for soil erosion control.

Many river trees, like willows,

  (willows tree)

cottonwoods,

  (cottonwoods)

  (cottonwoods tree)

and poplars,

     (poplar tree)

have this marvelous, persistent ability to sprout. It’s an important part of their survival. Many of these trees have long, whiplike or brittle branches that break off in winter and float downstream. The heavier end eventually settles somewhere in the wet mud and sends out roots, and a new tree begins growing.

  (poplar tree)

Key Attributes of Poplar Trees

• Very rapid growth
• Easily propagated from stem cuttings
•   (poplar tree)
• Availability of wide range of improved varieties through industry and university research
• Deep rooting

  (poplar leafs)

• Allow higher waste loading rates than conventional crops
• Minimal site management, with harvest once every 6 to 12 years
• Tall, dense structure provides visual and odor barrier for site operations
• Provide wildlife habitat

( Eucalyptus Tree)

 

For water reuse projects, we have the capability to offer large cost savings to our clients by replacing traditional grass or field crops with poplars. Because poplar trees have such a tremendous uptake capacity, less land is needed to absorb the given volume of reuse water.

(poplar trees)

When to plant. The best time to plant willow cuttings is in the fall or very early spring — when we call the tree dormant. Actually, only the leaves are dormant. The roots continue to grow all winter from stored energy, and when the buds burst in the spring, the new leaves will have a healthy system of roots to provide them with moisture and minerals.

Re vegetation techniques

Re-establish vegetation as soon as earthworks are completed. The plants will provide a protective groundcover, slow water flow, reduce excessive soil water, and bind the soil. Non-dispersive topsoil may have to be brought onto the site to produce a level finish and establish a rapid vegetation cover.

Plant species for specific functions

Grass will provide a fast growing cover on new earthworks. Vigorous, growing grass will encourage microbial activity which will, in turn, improve both soil structure and aggregate stability. The composition of annual and perennial species to be sown should suit the local climate and soil properties. Annuals provide quick cover and protection and perennial species have extensive and deep root systems that bind the soil and promote water uptake. Trees planted above and around the reclaimed area will prevent soil water building up and creating an erosion risk. Choose plant species suitable for your site.

Replace vegetation

     ( Eucalyptus Flower)

A mixture of quick growing trees and shrubs planted 3–5 m apart will intercept rain in the tree canopy, bind soils, lower the water table, and generally stabilise the slope. The best trees for revegetation of mass movement sites are rapid growing, have extensive root structure and a high transpiration rate, and will tolerate the soil conditions.

For example, a single eucalyptus tree

 ( Eucalyptus Flower) ( Eucalyptus Tree)

can remove up to 500 litres of water a day under favourable conditions. Choose species that are already growing naturally on similar soils, slopes and aspect. Careful stock management is necessary to allow trees to re-establish and to maintain at least 90% soil cover.

Divert runoff from the top of the slip.

• Smooth out soil debris to help regrassing and prevent weed invasion.

• Plant trees upslope, on and around areas of severe landslip. Close spacing of trees (3–5 m) can reduce the probability of slope failure by up to 70%. ( Eucalyptus)

• Exclude grazing animals while grass and tree plantings establish.

( Eucalyptus)

Blog 109-365

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