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Tunneling into School

What? Why would anyone want to tunnel back into school? Well, I have no idea, but in the past six years have I have been investigating how to build living tunnels in school grounds and gardens and have learned a thing or two about willow tunneling.

‘Tis the season… the season where the trees drop their leaves and go to sleep for the winter. The essential life energy is then held underground, and any alterations to the branches will little be felt. That is why working with willow is winter work. I’ve found that willow cut while the leaves are out ‘out of season’ have a 15-40% success rate when transplanting as cuttings. That 40% is only won through flooding the plants every two days in their first year. Willows transplanted in late fall to early spring, while they are dormant, have an >85% success rate, as long as they are cared for, kept damp-through mulching, soaker hoses, etc., and there are no air pockets which frost out the underground life of the cutting and turn black. If they have made it through the trials of year one, they will likely thrive and produce abundant offshoots, which can then be transplanted or harvested to make crafts and sculptures, or used as a rooting hormone when soaked in water.

You’ve probably never thought about it, but there is a set of codified rules for what is safe to install in school grounds. In Canada there are rules set forth by the Canadian Standards Association, and include much of what you might expect: choking hazards and the like. As we love to do with rules, they are broken into categories and made specific; measurements and testing tools for hip, head and limb entrapment, a delightful series of rules about protrusions, and many standards for materials, surfacing and grade. The simplest method for avoiding these figurative headaches is to use asphalt, grass, and chain link fencing. By far the most challenging route to designing these spaces is to take irregular and decomposing natural materials like wood, plants and trees. This is precisely what Heidi Campbell and Evergreen do. Alongside them I have learned a few tricks: try and design living structures whose woven cells are over 9" x 9" (23 x 23cms). This means no one will get trapped. Anything sticking out — protruding — has to be cut so that its length does not exceed its width.

Upon first hearing these rules I assumed that a living tunnel should be fully woven, so that no one will get stuck. As it turns out, children love to test structural stability, so despite my attempts at designing without nails, anything woven with green material, once seasoned and shrunk, allowed the little hands to tear them apart (if left to their own devices; arguably you could direct their overabundant enthusiasm to rebuilding and tying the archways…). In the most recent design, the tunnel pictured in the film below has been planted with potted willow (since sometimes it is hard to get folks to water plants at school, especially in summer) and left to establish for a year before being woven into a diamond pattern. These loose branches cannot trap anyone, and are re-enforced by simple willow archways. Moreover, the living branches do not shrink, and the diamond pattern allows the plants to ‘fill’ in, rather than left to grow straight up into trees. The condensed lesson here is: simplify and focus on designing the living elements to do the work, rather than spending time weaving as if it’s a basket.

Tips for living willow structures:

  1. Dormant! ‘Tis the season — make sure you confine willow cutting and transplanting to when the leaves have fallen.
  2. Choose cuttings from your local clime — plants will do better if already adjusted to soil/weather conditions.
  3. No air pockets — ensure that bare root cuttings have no air pockets which can hold frost. Jump on them.
  4. Place cuttings 8" (20cm) into the ground.
  5. Weed suppression — ensure that for a 6" (15cm) minimum, all around the cutting, weeds are suppressed with mulch.
  6. Rule of thumb — ensure that cuttings are larger than a normal adult’s thumb. This seems to help them succeed.
  7. Water, water, water — every dry day in the first year. Get the kids to do it — watering can chain.

Tips for Living Tunnels in Schools:

  1. Involve kids — little hands can move mulch, make willow rope, etc. Every task is a teachable moment — you know, sense of ownership, cultivating a stewardship ethic and creating empathy for living things.
  2. Simplify design — use archways to give form, but leave weave until 2nd year.
  3. Use a diamond pattern created by two 30 degree angles. Bound with a willow whip in square lashing pattern, so willow fills cells created.
  4. All cells created must be larger than 9" (23cm) — to make sure no one gets stuck.
  5. Use potted material — existing roots will help success in first stressful year at school. The school ground can be a rough place for a plant.
  6. Arrange maintenance — ensure your artist/contractor visits twice a year.
  7. Find local knowledge to teach teachers; how to source, harvest, plant, weave and make rope — create curricular connections.
  8. Try and secure your own funding — or find local permaculture practitioners and see if someone will barter for baked goods.
  9. As with the previous list — water, water, water! More water won’t hurt, but less can kill. :P


  1. Click on “Forums” at the top of this page and search for the work “Agloo”.

    Imagine if your tunnels were the entry to an “Agricultural Igloo” shaped vine covered building ?

    I am proposing the tunnel part be used to provide various levels of shade to comfort for a moving room on rails.

    The tunnels could serve a number of purposes. Shade varieties for human and plant benefit could be very important.

    I am considering building a double shade tunnel – the inner one to support vines such as tomatoes and beans and an outer tunnel to provide some limited shade so the tomatoes don’t get cooked on the vines. A sort of natural shade cloth.

    I am experimenting with plastic lined garden beds and maybe these could help sustain the willows moisture. They appear pretty strong archways.

    The approaches you are taking are not just child’s play – well done!

  2. Did the planted trees stay alive? – none of the photos showed them with many leaves !! I would have thought it looked great in summer.

  3. hi Lumbuck.
    i didn’t fully realize how strange it is to write something about living willow, and show pictures of cedar and other non-living structures.
    some of the success rates are written into the article, but a recent revelation (for me) is that longer uprights die back if planted in the fall in our significant winters (in toronto). if they are cut in early spring before they bud, put in water to root, and then carefully transplanted they can do very well. small 8″ cuttings can be done in the fall though.
    we have a 20′ x 20′ space with simple ‘mister’ attachments on hoses directing mist into the steel raised planters which contain about 15′ of willow shoots woven into tunnels and domes. these beds are interplanted with a bunch of stuff (blueberry patch, currents, artichokes, strawberry, etc). this feature is a principle way we keep the kids cool in the hot summer programs, with the obvious added benefit of the shade provided by these abundant willows.
    so yes. they do stay alive (i just have photos from the installation).

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