Friday, October 16, 2015

"Back to Eden" - Using Woodchips like Nature


All by Herself

     In permaculture, we realize that the best way to design is by observing how nature is designed and how she functions. In the woods, there is constantly rotting, decomposing "stuff" on the ground. Leaves. Straw. Branches. It's all decomposing with the help of decomposers. It may take a decade for a fallen tree to completely decompose but, eventually, you won't be able to see it anymore.

With Our Help

     We can mimic that same process and try to do it even better. If we shred or chip the wood into small pieces, that will make them decompose faster. Adding these wood chips to our forest garden does three important things:
  1. Lessens water evaporation
  2. Increases nutrients slowly
  3. Creates a better environment for helpful organisms

Lessens Water Evaporation

     We are often taught that the water cycle happens far away at the ocean, at the top of mountains and deep below the ground. While that's all very accurate, the water cycle can easily cycle through the three important steps in the first couple of inches of the ground. The water can condense on the underside of a small plant, precipitate to the ground and evaporate back upwards and never leave that area in the process. 

Rainforest nutrient and water cycle
Notice that many cycles take place between the ground ant the tree tops
     Adding wood chips keeps much of the water that has fallen from evaporating back into the atmosphere. These pieces of trees also absorb water and store them like a sponge. This increases the amount of water the ground can "hold" before water starts rolling downhill. This is called saturation. Wood chips help nearby plants by holding water which reduces how much water we need to add for plants to live.

1Y01-022a  Earthworm  - in burrow, note castings at surface - Lumbricus terrestris
A worm making tunnels which help other organisms

Increases Nutrients Slowly

     Worms, bacteria and fungi are three main organisms that literally live to decompose. These decomposers will slowly turn the wood chips into nice, nutrient-rich, plant-nurturing, tasty-fruit-producing soil. Worms do this by making tunnels up, down, and sideways in the dirt as they munch on the rotting tree material (see above). Fungi will start sending out white, thread-like tentacles that wrap completely around wood chips like a squid eating its prey (see below). Bacteria are invisible to our naked eye but they work so hard, our big pile of wood chips at PGM actually steams in the fall morning air. 

Scots Pine before adding mycorrhizal component and after.


Creates an Environment for Living Helpers

     The worms, bacteria and fungi show up because they want to live. But while they're there, they are able to make the area even better for their neighbors, the plants.  Worms make little tunnels for roots to fill in. Fungi create a Avatar-like communication and resource network that can be very beneficial to nearby plants. Having a healthy environment in the soil makes it much easier for plants to thrive. They kill harmful pests and supply fertility to the plants. This is a great example of a commensalistic relationship. The plant is helped and the other organisms are unaffected.


Summary

     All of this and more can be found in resources like "Back to Eden" video which is a story of a guy who uses wood chips to decrease the amount of labor that he has to put forth into his property. Our wood chips are going to hopefully nurture healthy plants. The wood chips should decrease the need for water and they should also decrease the need for inputs like fertilizers, herbicides, and insecticides.

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