Week 9: Windbreak Design

The last large section of the garden left to complete is the windbreak in the South-Western corner. Upon visiting the site for the first time one of the first things we noticed there was the strong wind coming in from that direction by the angle on the serviceberry trees. It was made even clearer when our cardboard sheet mulch kept having to be reinforced due to the intense gales of wind. Wind is an extremely erosive force, and can put stress on growing plants, so we designed the windbreak to protect the plants and soil and stabilize the temperature in the garden.

serviceberries

The angled serviceberry trees indicating strong winds. 

Our windbreak consists of three staggered rows of trees, with the tallest in the middle so the canopies form a triangle shape. This configuration guides wind upwards and over the garden, sheltering what is left behind it. Since the windbreak takes up a significant amount of space, it is important that it is multifunctional, so the species were selected to perform a variety of functions on top of sheltering the garden. We used this space as an opportunity to showcase some other interesting trees and shrubs that are a bit more unusual in a traditional garden, but that still are fast growing and strong enough to resist the wind.

We kept the four serviceberry trees that were already on the site that provide berries for harvesting and for sharing with the birds in the area. This ties in with the third ethic of permaculture: “Fair Share”. It is important to include plants and habitat that birds and the local wildlife will enjoy to really create a functioning ecosystem, in return they will provide ecosystem services like controlling pest and insect populations, and fertilizing the soil.

Added to the serviceberries are a pair of hazelnut trees that produce edible nuts, as well as food and shelter for wildlife. They can also be coppiced (cut to create a thicket of smaller branches) and the wood cut down can be used as stakes, fencing, building, etc…

Another edible berry producer we included is the Saskatoon Berry, which is really a fairly tall shrub. Its ornamental flowers attract bees, and its berries are similar to blueberries and are good food for birds or can be eaten fresh, baked, dried, or preserved in jams and jellies.

A good example of a very multi-purpose plant we included in the windbreak is the Siberian Pea Shrub. It is a pioneer species that grows very quickly in disturbed areas, to the point of earning the ‘invasive’ label. This large shrub produces seed pods that are edible, as well as the seeds within them (although they were used as a food source much more in the past rather than now).  It is also a legume that fixes Nitrogen in the soil, provides nectar to pollinating insects and wildlife, and acts as a shelter for birds. Its large root system also helps to stabilize the soil and control erosion.

Finally, another fast-growing Nitrogen Fixer in the windbreak is an Alder tree. Like the Pea Shrub, it is also a pioneer species that is good for transforming farmland back into woodland by replenishing the soil with nitrogen and covering it with leaf litter. Although it doesn’t produce any food, it does provide wood from coppicing, shelter for wildlife, erosion control from the roots, and can be used as a living trellis for climbing species.

The final row is berry bushes on the berm of a second swale that separates the windbreak from the squash garden and food forest.

windbreak

The plan for the windbreak design. 

Although we still have not received our trees due to complications in the ordering process, we have planned out and dug all of the holes, so all that is left to do is actually plant them! There is also the possibility of planting other canopy layers beneath the trees that will likely come at a slightly later phase in the design execution. Since the trees are placed quite close together there will not be a lot of light or space between them, but groundcover or vines could be an interesting addition.

Sources:

 

“Functions of Windbreaks”. Regenerative.com. Regenerative Leadership Institute, Inc., https://www.regenerative.com/magazine/functions-of-windbreak. Accessed 15 July 2017.

Joy, R.J. ” Windbreaks for Agroforestry Fresh Ideas With Multi-Use Species”. USDA-NRCS Plant Materials Center, 16 May 2006, https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/hipmssy6712.pdf. Accessed 15 July 2017.

Kitsteiner, John. “Windbreak Plants for a Temperate Climate”. Temperate Climate Permaculture, 26 July 2012, http://tcpermaculture.blogspot.com/2012/07/windbreak-plants-for-temperate-climate.html. Accessed 15 July 2017.

“Windbreaks”. A Permaculture Design Course Handbook. TreeYo Permaculture. https://treeyopermacultureedu.wordpress.com/chapter-6-trees/windbreaks/. Accessed 15 July 2017.

 

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