Tunnels of drought-tolerant plants in the drylands to combat desertification and feed people and livestock.
by Prof. Dr. Willem VAN COTTHEM (Ghent University, Belgium)
When I tell people that this is feasible, they ask me if it’s only a dream. And yet, it would be easy to construct ten thousands, even one hundred thousands of living tunnels. It suffices to choose available wooden species (trees and shrubs), native or adapted to the region. Here is a non-limited series of examples for the drylands of Africa, but one can certainly make a list of Asian, Australian or American species too:
Acacia sieberiana var.woodii (Paperbark),
Acacia baileyana (Bailey’s Acacia)
Olea europaea subs. africana (Wild olive),
Moringa oleifera (Moringa)
Brachylaena discolor (Wild silver oak),
Salix matsudana var. Navajo (globe willow),
Combretum spp. (Bushwillow)
Quercus agrifolia (Coast Live Oak)
Cussonia paniculata (Highveld cabbage tree),
Lagerstroemia indica ‘Rosea’ (Crape Myrtle ‘Rosea’)
Hymensporum flavum (Sweetshade Tree)
Vachellia drepanolobium (Whistling thorn),
Sutherlandia frutescens (Cancer bush),
Coleonema pulchellum (Confetti bush),
Portulacaria afra (Elephant bush),
Acanthosicyos horrida (Nara Plant)
Rhus lancea (African Sumac)
In 2003, I brought home from Arizona a couple of cuttings of the drought-tolerant Navajo willow (Salix matsudana var. Navajo) and planted them in my garden in Belgium. They were rooting and growing extremely quickly (as Belgium is far from being a dryland). Today in 2016, they reach a height of 14 meter. In April 2011, I started building a teepee with cuttings of my “Belgian” Navajo willows. It soon became a nice “living hut”, which brought me to the idea that it would be possible to construct “living tunnels” with similar cuttings of drought-tolerant trees or shrubs.
Without exaggeration I can tell that I always get a sort of happy feeling under the canopy of trees or in a tree tunnel. Most trees can easily be sculpted by pruning into many forms, thus altering their growth. One of these forms is a tunnel. One can use it as an excellent construction for a shady walk, but my thoughts are oriented upon an application as a fantastic location for family gardening (a kitchen garden) in the drylands.
Let us have a look at some examples and thereby imagine that a family in the drylands could use these as a “garden”, where, in the shadow inside the tunnel vegetables and herbs, even fruits, can be grown to feed the family.
Now, let this be a dream for nomadic people: living houses here and there along the track. Nevertheless, even this dream can be realized !