Permanut: Nuts for Regenerative Design
If you’re into permaculture and the design of regenerative, perennial food systems, nut trees are an obvious choice to include as a cornerstone of your design. There are a lot of ways to get leafy greens; however, plant-based proteins and fats are relatively hard to come by, especially in temperate climates. Nuts are an incredible source of both. Chestnuts are also high in starch and in Europe they were once known as “the bread tree.”
Nut trees are some of the predominant trees in many ecosystems, from oak savannas to hickory and walnut forests. Mimicking savanna and forest systems is a cornerstone of permaculture design: by reproducing the patterns and relationships of natural forests, we can design resilient, productive systems. It is possible to look to the plant families that thrive in particular contexts and select productive and edible species from those families. For instance, chestnuts (Castanea spp) is part of the Fagaceae family, and may be able to occupy the same niche as native oaks in a savanna context.
Walnuts and hickories, in contrast, do best in the rich soils of valley bottoms and other areas that were once forests. That said, there is huge variation within these families, and trees can’t simply be substituted for each other. These patterns are simply starting points for experimentation and design. The best way to figure out what grows well in your region is to observe what specific species are already doing well. In Victoria, BC, for instance, vigorous seedlings of Persian walnuts have been planted by squirrels that didn’t return to their stash. These patterns can be a clue for the design of resilient systems: if a nut tree can thrive without any human intervention, it’s well-suited to its context.
None of this is new; on the contrary, the cultivation of nuts is ancient and preceded annual agriculture in many places. For instance, archaeologists have determined that hazelnuts formed a crucial part of the diet of Europeans as far back as 8900 BC. Persian walnuts have been found at settlements dating from as early as 7000 BC. Before colonizers deforested North America to make it ‘productive’ (i.e. grazed animals and grew annual crops in a pattern that repeatedly degraded soils), Indigenous peoples throughout Eastern North America actively managed forests to promote the growth of chestnuts (Castanea dentata). Early settlers were shocked at the abundance of flora and fauna in America, but most failed to recognize the complex management systems of Indigenous peoples.
Nuts have been cultivated as an important staple crop all over the world. Here at Nutcase, we want to make the case for reviving and reinventing perennial food systems in which we grow more of our staple crops on trees.
The vision of a harmonious polyculture of plants, each of which performs multiple functions that save time and reduce the need for inputs, is what attracts many folks to permaculture. At the same time, a vision of a food forest that requires no effort from humans seems closer to fantasy than to reality. Most permaculture designs don’t eliminate work; they result in different labour processes throughout the season and the life of the system. For this reason, we emphasize the need to design ourselves into our systems: what do we like doing, what do we hate doing, how long do things take, and how can we design systems that save us time, cycle nutrients, build soil, support diversity, and enable us to do more of what we love?
Beyond their most obvious yield of nuts, nut trees are multifunctional plants that are a great fit for permaculture-inspired polycultures. Some nutty functions:
- Shade and cover for animals, plants, and people: chestnuts, walnuts, and heartnuts all produce big, beautiful canopies that lower daytime temperatures and filter sunlight. The bushy habit of hazels creates excellent cover for chickens to hide from hawks and other aerial predators. Sheep and cattle are regularly integrated with nut trees in agroforestry and silvopasture: herbivores keep grass down around the trees, their manure enriches the soil, and the trees keep animals cooler in the summers and warmer in spring/fall.
- Fuel, fencing, and fodder: hazelnuts can be regularly coppiced (once every 5-10 years) and they produce long, flexible poles that can be used in wattle fencing, trellises, furniture, and other sources. They can also be fed to livestock and used as fuel. In parts of Europe, pigs were historically fattened on chestnuts and this relationship has been maintained in some silvopasture system.
Timber: at the end of their lives, nut trees can produce valuable, high-quality timber.
Walnut is some of the most sought-after wood in temperate climates, and chestnut is an amazing rot-resistant building material. Walnut and chestnut can be pruned with eventual timber production in mind and can produce thousands of pounds of nuts along the way.
- Hedges, windbreaks, and privacy screens: the bushy habit of hazelnuts and korean pines lend themselves well to hedges and privacy screens. Hazels also sucker and can form a thicket. To create a hedge (or ‘fedge’ - food-hedge) consider interplanting with nitrogen-fixing shrubs like autumn olive, ceanothus, or goumi.
- Hunting: for most gardeners, deer are a problem to be excluded by fencing or other forms of protection. But chestnuts are regularly planted by hunters specifically to attract deer.
The specific needs of each nut tree species varies, but here are some important design considerations:
- Light: all our nut trees will produce optimally in full sun. That said, partial shade has its advantages in some cases. Korean pines require partial shade while they’re getting established, making them a great candidate for the forest edge. Hazels are similar: though they’re planted in full sun in orchard settings, they are adapted to the partial shade of forest edges and glades, and they’ll require less water (and yield fewer nuts) with partial shade.
- Pollination: chestnuts, walnuts, hazelnuts, and pinenuts are all wind-pollinated. Unlike apples and stone fruit that can be pollinated at a distance, nut trees will produce best when they are in close proximity to members of the same species that can transfer their pollen in the breeze. All seedling trees (unlike trees cloned by grafting or layering) are genetically unique individuals that are capable of pollinating other trees of the same species. However, the timing of pollen shed must overlap with the receptivity of female flowers, and this can vary such that neighbouring do not pollinate each other effectively (this can be an issue with hazelnuts specifically). For this reason, we recommend planting several of the same species in a row or a block, so that each tree has several potential pollen sources.
- Water: the water needs of our trees are highly variable, which means there is a nut tree for almost any context. If you have sandy, well-drained soil, consider chestnuts or pines. Hickories are on the other end of the spectrum thriving in moist or even waterlogged soils. Hazels and walnuts are somewhere in between: while we’ve read that hazels won’t tolerate waterlogged soils, we’ve observed them growing well in soils that are entirely flooded during the wet winter months. While some trees may be able to make it on their own depending on your climate and your site, it will be important to monitor them regularly and have a plan for watering in the event of drought.
- Protection: all trees need protection from voles, and we think the best way to deter them is with mulch. See more on this below and on our ‘mulch musings’ blog post. Almost all our trees (except perhaps pines) will be grazed by deer. We have experimented a bit with sprays and ‘decoy’ plant ideas that appear on some permaculture websites, but we haven’t had success. Proper perimeter fencing works great, but it’s expensive and labour-intensive. Metal cages work well as long as they’re staked well. We’re currently most impressed by tree tubes, and we've made them available on our website. In addition to providing protection from deer browse and buck rubbing, they provide a greenhouse effect that accelerates growth. The material is UV-resistant but it is not designed to be reused: they are designed to be left on for a number of years so that they continue to protect the bark from buck rubbing. It is possible that they could be cut away from the tree and reattached to a younger tree using zip ties. Dogs can also be an effective deer deterrent, but many folks bring their dogs inside at night, and in many regions deer are active at night or dawn/dusk.
- Reduced weed pressure: nut trees will certainly benefit from the management of weeds around the base of the tree, and the question of management is (to us) a very interesting design question. Many conventional nut orchards simply spray glyphosate so that there’s nothing alive but nut trees and bare ground. That’s not something we’re interested in, so it leaves a few possible weed management options:
- Mowing: cutting grass and other herbaceous plants around your trees--especially at specific times of the season, can have major benefits. It reduces competition for water and nutrients. It also causes root die-back among the grasses, which can feed the trees. At the farm where Nutcase is based, we grow other perennials in amongst our nut tree rows, and we use an electric push mower to keep the grass down between rows. This does the trick, though at a large scale, you’d probably want a riding mower for this task. Perhaps the most elegant stacking of functions for mowing is the use of livestock in a rotational grazing system. Not only does this keep grass down, but it has a huge effect on nutrient cycling and soil-building. There are a lot of inspiring examples that integrate livestock and trees in the worlds of permaculture and agroforestry (check out the resources below). We use an electric push mower here at our farm and it does the trick
- Mulching: wood chips can be an amazing resource for establishing nut trees. Research has shown that ramial wood chips in particular (chips of deciduous branches < 2 ½” diameter) can feed fungi and help accelerate the development of rich soil. They reduce competition around the trees (for a year or two, anyway). Spreading wood chips is very labour-intensive, and it can also be difficult to find an affordable source. We don’t recommend plastic or straw mulches, because they create an ideal habitat for voles. As an alternative to wood chips, we also sell hemp mulch mats. We are trialling these on the farm and we can’t attest to exactly how long they’ll last, but they are not a long-term solution: they are a way to exclude weeds when your tree is at its most vulnerable. For a deeper dive into mulching, see our ‘mulch musings’ blog post.
- Perennial groundcover: perhaps the most intriguing and complex solution is to establish other plants that outcompete weeds or don’t allow them to become established. Over the past few years, we have been trying to pay attention to hardy perennials that ‘beat grass’: plants that can outcompete grass and other tenacious weeds while providing beneficial functions. So far we are focused on comfrey, daylilies, and alliums. These are all drought-tolerant and their bulbous/rhizomatous root systems seem to make it difficult for grass to get a foothold. But there are still some unanswered questions and concerns. It’s not clear how much they’ll compete with the trees for water and nutrients. Understory plantings could also make harvesting more difficult. The ideal understory would be something that could be mowed low before the nuts drop, so that nuts can be easily harvested from the ground. Finally, living mulches coil create a habitat for voles, which can quickly destroy trees. We may try to propagate some understory plants to offer them for sale in the future. We are always on the lookout for more possibilities here. If you’ve had your own successes with perennial groundcovers around the base of your trees, we’d love to hear about them!
Succession and Polycultures
The concept of ‘plant guilds’ arises from the permaculture approach of mimicking patterns of the forest in which a variety of plants occupy different niches and perform multiple functions that support the overall system. These plant assemblages can build soil, attract pollinators and beneficial insects, support birds and other pest predators, and fix nitrogen. Larger nut trees (chestnuts, walnuts, heartnuts, pines) are a great candidate for the top canopy tree of your guild, and hazelnuts can be a great understory tree.
An example of Tim Murphy’s walnut guild in Toby Hemenway’s permaculture classic, Gaia’s Garden. Hemenway writes:
If you're looking for high-quality fruit trees and shrubs to combine with our trees in your nutty designs, we recommend our friends at Tree Eater Nursery and Denman Island Heritage Apples, which are both here on Denman Island and offer shipping throughout Canada.
Ornamental yet habitat-providing shrubs such as elderberry, hackberry, and wolfberry grow well under the stately walnut tree. Currants, tomatoes, and peppers supplement the walnut harvest. The mulberry and Elaeagnus create a transition to other plantings in the yard, protecting neighboring plants from the walnut’s allelopathic effects.
The walnut tree is one of the patriarchs of the plant kingdom. Behind my parents’ home in Illinois, a mighty black walnut arched over the back deck, and on many mornings I lounged in its soothing shadows with a good book and a mug of coffee. Along with shaded pleasures, walnut trees offer many other benefits. They yield delicious nuts and delight us with the scampering of squirrels among the branches in search of the tree’s bounty. Even the nutshells have uses, for dye and abrasives. Walnuts also provide premium-quality timber that brings in a hefty sum and is a cabinetmaker’s delight. The trees are drought-tolerant, too, and can thrive in the arid Western states as well as in less harsh locales.
Choosing companion plants for walnuts is tricky because this genus is allelopathic—that is, the plants secrete a toxic substance (in this case, one called juglone) that suppresses competing plants. Very few species can thrive under the canopy of a walnut, and vegetation near the trees is often stunted. But once again, observing nature nudges us toward a solution. By observing what juglone-tolerant species naturally associate with these stately trees, Tim Murphy has evolved a guild of walnut-friendly plants.
Modified and extended guilds
Permaculture guilds like the one above are often designed in a circle or with complex crenellations and keyhole paths.
Various paths and keyhole designs showcased in Dave Jacke's Edible Forest Gardens Volume II, p103.
These natural patterns of branching can be incredibly elegant designs. Dendritic patterns (in rivers, branches, lungs, etc) are the most efficient way to transfer energy in natural systems, and they can be efficient in the garden as well. At the same time, depending on the equipment, tools, and social systems you're using, rows might be the best choice. For instance, in a context where not everyone is intimately familiar with the system (e.g. a community garden or a farm with volunteers) rows can help make things legible and easy to explain. In these contexts, legibility is crucial: imagining telling an inexperienced volunteer where to drop a wheelbarrow of mulch in what appears (to them) as a maze of interchangeable winding paths.
Rows can also help organize and simplify planning, planting, maintenance and harvesting while retaining the benefits of polycultures. Rows don’t necessarily need to be straight lines: they might be placed on contour or on keylines, as in this large planting that includes thousands of hazelnuts and chestnuts at New Forest Farm:
Designing with Succession
In most introductions to permaculture, guilds also tend to be represented as a mature system, but that doesn’t tell us much about how to establish these systems, or how we might interact with them during the years of establishment. One of the permaculture principles is “obtain a yield” and if nuts are the only yield in your system, you’ll be waiting a while. Depending on the species and its context, nut trees will take 3-10 years to produce. In the first few years of establishment, nut trees often look like spindly poles with huge spaces in between.
But these spaces are opportunities to design for succession. This is often called ‘stacking in time’: rather than planting based on mature spacings, plants can be grown more densely to mimic the patterns of forest succession, in which annuals and shorter-lived perennials are eventually succeeded by longer-lived species once the trees develop larger canopies. Some ideas:
- Annuals (including vegetables) can be grown around your trees. Be careful not to disturb the roots of your establishing trees (i.e. if you’re planting nearby, avoid things like potatoes that require digging). At a larger scale, this is known as alley cropping and annual crops (grain as well as vegetable crops) are grown in the alleys between tree rows.
- Precocious perennials: consider planting trees or shrubs between nut trees that will produce a crop more quickly (e.g. apples/pears on dwarf rootstock, cane fruit, etc)
- Nitrogen-fixing 'nurse plants': consider trees or shrubs that fix nitrogen and grow quickly. These are often called 'pioneer' species because they thrive in disturbed or degraded land and build soil before being succeeded by longer-lived species. When they are cut back, these plants release nitrogen in the soil and feed the other plants in your system.
- Shade-tolerant perennials: at the same time, consider establishing perennials underneath larger nut trees that will continue producing under partial shade (e.g. currants, gooseberries, pawpaw, and hazelnuts)
This concludes our Permanut post (for now!). We intend to treat this page as a living document and we'll be dropping in more links and ideas as we go.