A Mere 20 of the Roles Trees Can Play in Permaculture Design

While permaculture certainly pays mind to annual crops, by and large it is a system rooted in perennial plants and, in particular, trees. Permaculture, as the “perma” name suggests, is a movement towards permanent agricultural arrangements, ones which culturally value nutrition, systemic health, and sustainability over monetary wealth and materialism. Permaculture designs can be quite complex cycles for avoiding waste creation and maximizing productive efficiency, but they are fairly simple in their pursuit: Humans must give back via a combination of returning our surpluses to the eco-system and clever settlement configurations. Planting trees is a great avenue into doing this.

When speaking in permaculture terms, thinking of trees as only providers of food crops, especially with a focus on profits, is a gross underestimation of how valuable they are to the overall ecology on the particular farms where they are found, the microclimates in which those farms exist, and the planet as a whole. Trees, even fruit trees, are much more than apples or oranges, and it is through the recognition of the many varied roles of trees that permaculture designs are able to create permanent ecosystems of abundance. In other words, why we plant trees in our systems requires an answer with so many layers it’s almost impossible.

But, let’s get that list going anyway…

Apple Tree (Courtesy of Brad Greenlee)

Why wouldn’t we start with food? Food is certainly part of the reason why we choose to include many of the trees that are in our designs, but we shouldn’t be so oblivious as to think growers are the only ones benefiting in this arrangement. The food lines run much deeper than that.

1. Well, it can’t be denied that trees do supply an abundance of food, including not only fruits but also nuts, leaves, seeds, flowers, saps, and—in some form or fashion—every other part of the tree. Obviously, trees can provide much more of this per square meter than small, short-lived annual plants can supply and for much longer, so credit is given where credit is due.

2. But, the food isn’t just for us. Many trees make great animal fodder, which adds a variety of nutrients, including plenty of protein. This is a great addition to the diet of penned animals, and established trees are typically much more resilient than herbaceous plants, allowing them the fodder to continue in times of drought. The diets of wild animals, too, rely heavily on both things that grow on trees and things that live in, on, and around them.

3. Then again, we mustn’t limit the role of trees as food to only animals. Trees drop leaves, twigs, fruits, and other organic matter to create their own mulches and nutrients on the forest floor, providing themselves with food, as well as food for an abundance of microorganisms, bacteria, fungi, shrubs, and other plant-life. In fact, certain trees, like nitrogen-fixing legumes, are grown within permaculture systems primarily to feed other trees and plants.

4. Ultimately, economics can factor in as well, as only a few fruit and nut trees often supply far more food than any one family can eat, so the surpluses can be used in local markets or for trade. This economic exchange can be viewed from both sides, with those seeking a certain crop at a fair price or trade also benefiting from the surplus.

5. Finally, just to take on another aspect of the edible tree, we should forget than many trees have notable medicinal qualities, with polyculture forests having the ability to treat everything from fever to diarrhea to gout to cancer. While modern medicine has no doubt provide us with some health advantages, it pales in comparison to the power of nature.

Acacia (Courtesy of Enzo Fiorelli)

But, food is an obvious answer. Trees are much more than food. They have the ability to do a lot of work for us and for the soils we rely on. Because modern agricultures tendency towards deforestation, we have seen a huge loss in topsoil, and trees are huge part of creating new soils and protecting them.

6. All of the detritus dropped from the crowns of trees and the ultimate collapse of dead trees, the rotting of roots beneath the surface of the soil, it all goes into building new humus. A new forest grows on an old forest. Permaculture designers, recognizing this, often use fast-growing, short-living trees, chop-and-drop techniques, and coppicing/pollarding to produce this soil-building more quickly.

7. But, trees also stabilize soils. Their roots spread out into them, their leaves mulch them, their crowns prevent heavy rains from eroding them, and their groupings control winds that might whisk away fertility. In other words, when we take all those trees away in order to plant cash crops, we are leaving that soil highly vulnerable.

8. Trees, too, help to keep soils moist. Though many growers worry trees will take away water from their plants, this is a miscalculation. Because trees provide mulch, because they provide shade and stop evaporation, because their roots often reach much further beneath the surface in search of water, because they prevent winds from drying soils out, they actually help to keep soils moist.

9. In the same breath, trees also help to regulate soil moisture levels. In areas that may otherwise be waterlogged, thirsty trees will take up the water and put it into useful biomass that can be feed back down, used for crops or crafts, and build soils back up to workable levels.

10. In fact, pioneering trees, the huge family of nitrogen-fixing legumes, help to condition damaged soils of all varieties, bringing back fertility and biomass. They also help to break up clay hardpans or add organic humus to quick-draining, sandy soils. In most cases, the abundance of organic material also helps to bring pH levels back towards neutral.

Black Locust (Courtesy of Art Poskanzer)

While we tend to think of tree products in terms of food, there are actually many other products that come from them, and designs strive to make the most of these. We can harvest from forest indefinitely if we care for them, or we can destroy them very quickly if we exploit them. Why not do it sustainably?

11. Lumber is a great, sustainable building material that can be grown responsibly. In fact, some trees are particular well-suited to providing lumber and crops, such as cherry and apple, which make beautiful items, and others, like black locust, are great for fixing-nitrogen and providing good lumber.

12. Firewood is another much-needed thing, as it can be used to cook and heat. Many trees can be coppiced or pollarded to provide firewood year after year, and these are also often nitrogen-fixing trees, which drop excesses of nitrogen into the soil every time they are harvested from.

13. Other trees, such as willows, have much smaller branches, and those can be used for crafting. Making products like baskets, rustic furniture, and carvings can all be wonderfully fulfilling hobbies, provide some income, and give us useful items from natural sources, as opposed to more plastic.

14. Then, there are trees that have particularly useful saps, such as rubber trees. These trees can be part of a system for many years, providing rubber, gums, glues, waxes, and so on. Tree sap is a more environmentally friendly way, often the original way, of providing very many common things that are now petroleum-based products.

15. And, of course, knowing that trees are great for the soil, they can also provide many useful garden products, far beyond shovel handles or bed borders. The leaves can be collected to make mulch, leaf mold, and compost. The trunks can be used to build hugelkulture beds. The logs can be conditioned to cultivate edible mushrooms.

Shade Tree (Courtesy of Sean Kelleher)

Products are great, but trees should probably be as appreciated for the functions that can provide, especially with regards to making homes more energy-efficient, gardens more productive, and ecosystems more stable. We can use fruitful trees for so much more than what they produce.

16. Windbreaks are vital on many landscapes. They protect gardens from damage. They help to prevent dryland soils from drying out. They keep cold polar winds off of homes, and/or they can funnel cooling breezes towards houses. They stop some of the erosive effects of winds, and they harvest organic materials and silt the winds have picked up.

17. Shade is equally as important in many of the landscapes we cultivate and places we build homes. Deciduous trees can shade homes in the summer and allow sun into them in the winter for passive solar heating. Palm trees can provide overhead shade in tropical and desert gardens. Shade is also where we like to put picnic blankets and benches for leisure activities.

18. Trees are also vital to the local water cycle. Their detritus allows water the chance to percolate into the soils, both feeding the plant life in it and the springs and streams running through it. The trees, in turn, transpire the water back into the atmosphere, increasing rain cycles. Meanwhile, they keep the understory moist by protecting it from evaporation and wind, as well as providing it with humidity.

19. This steady supply of wind-breaking, shading, and transpiration equate to moderate temperatures around trees. The heat of the sun is blocked out, the cold of the wind is pacified, and the moisture in the air is kept regular. Areas around trees are generally cooler in the heat and warmer in the cold.

20. Trees can also be used to create living fences or living fence posts, which cut down on material costs and farm maintenance. Plus, as with many of these other functions, these fencing trees can also provide useful outputs, like mulch, crops, and pollarded firewood. They also provide useful habitat for beneficial pest control animals and other wildlife.

Autumn Spring (Courtesy of Zoltán Vörös)

To say that we have exhausted the list of what trees can do in our systems and for the local and global ecology would be a horrible understatement to the prowess of trees. They are crucial system builders, even in prairie lands and savannahs, and when looked at as more than a source of income, they are almost like old friends, worthy of whatever attention and appreciation we can muster for them. To put it mildly, planting a tree is an exciting moment, it’s an honor, and it’s providing hope for the future.

Header Image: Entrance to the Back Woods…(Courtesy of Irene Kightley)



3 thoughts on “A Mere 20 of the Roles Trees Can Play in Permaculture Design

  1. Nice overview! One thing that I am missing under number 8 is the fact that the roots of some trees (still under investigation how the process exactly works) can also increase soil moisture via hydraulic redistribution. I wrote a blog about it in Dutch (see https://eenreiziger.blogspot.nl/2016/12/verbeterde-voedselproductie.html) but with Google Translate you should get most of it I think. More than 100 trees, grasses and shrubs have been identified that perform hydraulic redistribution.

  2. Excellent list. I have a few more to add. Tree roots help in moving nutrients around the forest floor, via mycorrhizal fungi. So it keeps the fungi population numbers up, and therefore the efficiency of nutrient spread in the forest.

    Nutrient accumulators. Trees attract a lot of lifeforms to them, and therefore draw a lot of nutrient drop from outside sources. Insects, bats, possums, birds, as well as heribores who use the shade of them to chew their cud, all drop their dung, so trees are nutrient accumulators.

    Muscle and coordination development. Trees as a structure, allow children and other mammalian juveniles of different species, to develop better muscle density and mental coordination, by learning to scale them.

  3. I know it doesn’t fit into your climate change mantra but probably the most important role of trees is that they provide up to 1/2 of the oxygen on the planet. Forests pump out oxygen we need to live and absorb the carbon dioxide we exhale (or emit). A single mature, leafy tree is estimated to produce a day’s supply of oxygen for anywhere from two to 10 people. Phytoplankton are more prolific, providing half of Earth’s oxygen, but forests are still a key source of quality air.

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