Tuesday, January 29, 2013

Hermit Park Slash Pile Burn Scar Remediation

As I mentioned last week, there is another project with Larimer County that Trailcology will be helping out with.  This project will remediate small fire scars where timber slash has been piled up and burned.  Management of these fire scars is important to help keep invasive plants from establishing and spreading into native vegetation.  When invasives spread like this it can be very costly to control the spread and try to eradicate the plants.

Slash piles are created when trees are removed for specific management practices related to forest health (recently there have been many beetle-killed trees removed).  The trees and all of the cuttings (slash) are piled up and left to cure until the appropriate conditions are met for burning.  Slash piles are only burned in the late fall to early spring time frame because there is usually more moisture and colder temperatures, which means there is a much lower risk of starting a forest fire.  When the piles are burned they have a strong effect on the soils directly below them.  Because there is so much fuel in an isolated location the soils experience a very extended period of high temperatures.  The heat can cause chemicals in the fuels to release onto the soil surface, creating a hydrophobic layer in the soil - a soil layer that resists water.  Additionally, the high temperature and long duration of the fire effectively sterilizes the soils, killing any seed sources for new plants.  Due to the impermeable soils and lack of seeds, native plants take a much longer time to establish on these small burn patches.  Invasive plants, however, are usually well adapted to establishing on disturbed sites.  This is primarily because of their ability to spread seed (think of dandelion seeds blowing in the wind) and establish themselves by germinating quickly.  Once a single invasive plant is established it will start to spread it's seed and it suddenly becomes a serious management issue.

To help prevent invasive plants from creating little monocultures on the burn scars there are a few simple treatments that we can administer.  It is important to treat these scars in the fall, winter, or spring because that is when the most moisture is available, giving the seeds the best opportunity to germinate when the weather warms up.  The first step is usually to break up the hydrophobic soil layer with a heavy rake.  Second, seeds are applied by hand.  Third, the soil is lightly raked to incorporate the seed.  Finally, the seeds and soil are protected from erosion and predation by applying a mulch of some form.  Then we let mother nature run her course and hope that the desirable native vegetation takes hold.

Here is the project release statement from Larimer County:

On April 6th there will be a volunteer project at Hermit Park Open Space to revegetate some of the fire scars where slash piles were previously burned. We want to do this to discourage weeds from moving into those areas where no other competition is present. Exotic invasive plants colonize disturbed areas with reduced competition from other vegetation, reproduce prolifically and then spread. Currently there are over 80 burn scars and another 150 slash piles that may be burned within the park. We'd like to take this proactive weed management approach because it reduces the use of herbicides and the overall cost, as well as protecting the integrity of the forest community at Hermit Park.

To register for this project please send an email to Casey Cisneros at cisnerct@co.larimer.co.us.  Please indicate that you will be volunteering under Trailcology.

This should be a fun day at a beautiful open space, hope to see you there!

Happy Trails,


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