This low-tech practice is an excellent way to reuse material from nearly any type of vegetation management project because it is quick, easy, and relatively low-risk. Lop & Lay Brush Wattles require minimal skilled labor to install. They can be applied in series down a slope to break up the slope’s length. 

These simple structures add “roughness” to a slope that interrupts the flow of water down the slope. They reduce surface runoff, retain eroded soil and organic matter, and create habitat for small animals. As the woody material breaks down, it can increase the permeability of soils (as in the left-hand picture), enhancing infiltration and providing nutrients to the surrounding forest. Brush wattles can help improve the soil’s water-holding capacity of a site and therefore its drought resiliency. 

• This Practice is appropriate for an upland setting, that is, an area of higher elevation in a watershed. 
• Brush wattles can only slow down a small volume of water. They should not be installed in the path of concentrated, high flow such as a stream, river, or drainage ditch. 
• Ideally, the wattle installation location is close to an overstocked forest or shrubland that needs to be thinned or limbed, to allow easy reuse of the resulting biomass as the material to build Lop & Lay Brush Wattles.

No permits are required for this practice.

It is important to know how to identify an on-contour line to properly place your structures. An on-contour line is a line across a slope where elevation remains the same along its length. Having a basic understanding of the energy, scale, and force of water flow entering your project site will also help you successfully scale and place your project. Considering this technique deals with low-energy water flows and material less than five inches in diameter, it’s unlikely that unintended consequences will pose significant problems.

1. Source and process your material.
   This practice is best paired with other vegetation management practices such as Limbing, Shaded Fuel Breaks or Thinning that generate biomass material. For this practice, woody branches, limbs, and small trunks roughly less than five inches in diameter at breast height are best, in addition to green, flexible coniferous boughs from trees like Douglas fir or Coastal Redwoods.Process and sort your material into piles of like sizes and types. On steeper slopes, avoid using large logs to prevent the possibility of them rolling downhill in the event of wildfire. Trimming may be necessary to ensure everything lies relatively flat.
2. Identify on-contour line(s) for your project.
   These can be eyeballed visually or laid out using measuring tools such as an A-frame or carpenter’s level. The number and vertical spacing along the slope should be determined by site conditions like slope gradient and soil type. Generally, the steeper the slope, the closer together the wattles should be.
3. Install your brush wattles.
   a. Clear away big branches or material on the ground that will impede your wattle from having solid contact with the ground. As you excavate materials, place them up-slope to later be incorporated into the structure.
   b. Lay brush along the slope in an interlocking fashion to create a bundle roughly up to six inches high. It can be helpful to install larger material first and then fill in gaps with smaller material or green, flexible material. Particular attention should be paid to both the front face of the wattle and the back side to serve as an energy dissipating “apron.”
   c. To reduce flammability, it’s best to keep the wattles low (under six inches) and in contact with the ground.

Variations on this Practice 

If you are concerned that flowing water may dislodge your Brush Wattles, wooden stakes can be easily made from wood on-site. Redwood limbs, for example, are durable and rot-resistant. Pound the stakes in an interlocking fashion on either side of your structure to create an X-shape. 

When thinning trees in an area where you plan to install wattles, consider leaving stumps as natural retaining posts for a wattle placed upslope of the stumps.

Timing Considerations 

It is best to implement this practice at the same time as, or shortly after, you generate the biomass material in late summer or early fall, to ensure the materials are green and flexible. It’s helpful if the finer leaves and needles are still intact and retain their filtration capacity when the rains arrive.

This practice is best done outside of the bird nesting season, generally from March through August in Sonoma County. This timeframe covers nesting season for the majority of songbirds and raptors (birds of prey). If the work is done during nesting season, consider first conducting Nesting Bird Surveys. Surveying over a longer period can protect more types of birds. For example, the Northern Spotted Owl can begin nesting as early as January in Sonoma County.

Equipment

Personal Protective Equipment (PPE)

• Long pants
• Long sleeve shirt
• Boots
• Gloves

Tools

• Hand saw
• Pruner and/or loppers
• 3-pound mallet if pounding in stakes

During and after rainstorms, visit your project to make sure the material you installed is functioning properly: 

• Check that water is not scouring around or beneath the material.   
• Observe how water is moving and where eroded material is settling.
• Adapt the project as needed.