This is the third of a series of articles looking at design considerations for our Cold Climate Permaculture site using the Keyline Scale of Permanence as a organizing framework, as well as an informative read for anyone interested.
P.A.Yeoman’s Scale of Permanence (SoP)
The first article introduced some basic Keyline concepts and looked at the site specifics and how the landform will influence the patterning of our farmscape. The second article looked at water and roads. This article was originally intended to address trees and buildings, but after consideration of the importance and wide scope of trees in our landscape, the focus will be solely on trees and how we are integrating woody aspects into our permanent agriculture. This article will follow these main topics, riparian zones, Keyline patterned perennial cropping, windbreaks and hedges, timber, coppice firewood and tree nursery considerations.
Tree patch overview at ridgedale permaculture for reference through the article
Trees are placed quite high in the SoP, potentially outlasting buildings, but more importantly perhaps, managed in ongoing relationship to the previous elements in the SoP. P.A. Yeomans used contour strip forests on his farm and proposed developments of Keyline landscapes.
Contour forest strips on Yeoman’s Nevallan
These are generally placed along water harvesting / irrigation channels. Trees usually border roads, and are located above irrigation channels, offering protection to water systems. In his excellent book from 1971, The City Forest, these forest systems are used to clean residential water whilst producing fuel within city boundaries. Not a bad idea. Detailed benefits of integrating trees with pasture / annual crops are expounded later.
The riparian zones protect the two streams that run through the property. Trees and shrubs serve to secure the banks of streams and water bodies, shade the water and filter run-off before it enters the course. Riparian zones, or buffers, are also important habitat. We can also crop in this area, and use periodical grazing whilst we establish the plant assemblies we desire. Naturally our riparians are well drained but may remain moist through snow-melt and field drainage, as well as occasionally flooding.
One of the steep banked riparian zones looking SSE from the road in the very center of the farm
Existing species include;
We can use these niches for cropping of fruit, nuts and timber as well as various shrub and herb layers. Occasional grazing and ideal sites for bee hives make this a multi-functional and productive zone. Additional species we will add include;
- Walnut (var.)
- Hawthorn (var.)
- Hardy Grape
- Hardy Kiwi
- Sea Buckthorn
- Service berry
Keyline patterned perennial cropping — Ground Preparation
Keyline patterned ripped & mounded high quality tree prep. Photo courtesy Darren J. Doherty
The front and back fields on the farm schematic above are the most intensive perennial cropping patches of the farm. They are patterned according to our overall Keyline layout, allowing for continued pasture development between the tree lanes over the subsequent years.
Pasture is not the optimum starting point for establishing trees. Grasslands are generally bacterially dominated through to balanced fungal:bacterial ratios in the late successional grasses. Shrubs and vines tend to thrive in F:B ratios of 2-5:1; whereas with our tree crops we are talking F:B ratios of 5-100:1 or more (up to 1000:1 with conifers and old growth forests). We also have compacted land that has not been grazed effectively for many years. So we need to prepare the ground for planting, lift compaction, deal with water and establish a multitude of support plants simultaneously.
This is where innovative use of equipment and allowing the geometry of our topography to pattern our farm will serve us very well. Below you see a quick sketch of the process of establishing our perennial lanes to this beautiful Keyline geometry. There are many ways to establish trees, with more or less technology. The scale we are working on, whilst not particularly large, suits the machinery we have at hand for an efficient and multi-functional result.
Our first job is to subsoil the paddocks on the Keyline patterning explained in the previous article. The tree lanes will then be marked out to the 12m spacings we are working on in the front and back fields. (More considerations explained further on.) The next step is some primary cultivation to disturb the grass — a mechanical weed-killer if you like. We will use a power harrow for this first pass, which has the benefit of not mixing soil horizons like a rotary hoe or plow, which could also be used.
Adapting the Keyline Plow for multiple tasks in a single pass. Photo courtesy Darren J. Doherty
On the 2nd pass we will deep rip with 2 or 3 of the 26” shanks on our Yeoman’s plow with a rotary hoe bed former trailing behind, the image above serving as an illustration of how this machine can be adapted for multiple functions. This will leave us with nicely prepared slightly raised beds for planting trees / shrubs and cover crops over deep rips appropriate to our desired planting pattern, with the furrows on each side of the bed performing like mini swales but on the Keyline patterning (as illustrated above). This patterning leads any excess surface flow out to the ridges and slows its movement through the landscape.
Keyline “pocket” ponds, photo courtesy Mark Sheppard
Mark Sheppard has adapted this technique with what he calls “pocket” ponds, that can catch and store excess run-off. These are ponds that are not necessarily designed to remain full all year long, but more to slow, sink and store water to make it an asset rather than a problem. At ridgedale we have laid out farm tracks to catch and move water passively around the landscape, anticipating the combined subsoiling and tree lane mounding (with dense planting) to be an effective water management strategy. The beauty of this layout and system is the ability to observe and adapt if necessary.
Species Assemblies & Planting
Cultivation of soil selects for bacteria. In addition, the cultivation will lead to a profusion of grasses. It does, however, give us opportunity to sow a diverse cover crop and plant trees and shrubs into well-prepared ground whilst dealing with the overall water considerations of the site. Our job as engineers of this designed process is to help steer everything possible towards the set of chain reactions (the succession) that we desire.
The mounded tree lanes are seeded immediately to kick start succession with doses of fungal-oriented compost tea. Once the tree mounds are settled the tree and shrub crops are planted as bare roots / modules at regular spacings. In the back field there are two rows of crops planted according to their height to maximize solar collection due to the general E to W row orientation. In the front field the main tree crops are planted over a central rip with shrub crops on either side, due to their N to S orientation:
Planting pattern for maximum solar gain. Note deep rips under formed tree beds,
with mini “swales” on either side of bed resulting from the bed former.
The trees and shrubs are of high value, and longer-lived perennials deserve a good start in life. Bare roots are dipped in diluted molasses to help kick start fungal symbiosis. Fungal oriented compost is applied with each planting, as well as covered with a thick spot mulch of straw or whatever is lying around to keep up moisture levels and reduce competition around roots during establishment. Commercial fungal inoculants can also be used, along with continuing compost tea applications throughout the season. Kelp and fish products can also be useful in boosting initial tree growth.
As with any design work, the mapping and conceptual design process leads us to an accurate digital layout where we can generate a bill of quantities efficiently. The length of tree lanes and our chosen spacings allows rapid calculation of plant stocks required. With nearly 1.5km of tree lanes in the front and back fields our cropping list includes;
Tree & Shrub Crops
- Apple 90
- Pear 40
- Plum 40
- Cherry 40
- Hazel (bush) 390
- Raspberry 620
- Currants/berries 700
- J. Quince 50
- Goji 50
- Elderberry 75
- Aronia 75
- Saskatoon 75
- Blue Honeysuckle 150
- Siberian Pea Shrub
- Sea Buckthorn (Driveway Planting) 360 (approx. 36 Male) (2m spacings with 6m between rows)
Differing planting patterns and assemblies will be used, but for a general picture we plan 7.5m spacings for fruit trees on semi-vigorous rootstocks. In the back field this allows the N side of the tree lane to accommodate hazel (bush) on 1.5m spacings with assorted berry fruits on 80cm plantings over the front rip. This solar oriented “forest edge” style planting allows maximum light for all plants on a more E to W orientation. These rows have 12m pasture strips between them, laid out on the Keyline patterning.
In the front field, where the plantings are roughly N to S, we also pattern the plantings for maximum solar gain, with tree crops over a third central rip and shrub / berry crops on either side. In all tree lanes a diverse assembly of support plants is undersown to support the main cropping trees / shrubs.
Our groundcover mix will be sown into the formed tree beds to quickly establish groundcover. The multiple benefits we are looking for are nitrogen fixing, mineral accumulation, edible crops, insectary and nectary sources as well as protecting the soil. Having perennial support plants helps tip the F:B ratios in our favor, and the addition of chop and drop mulch and woody compost from deconstructed biomeilers will ensure a good supply of fungal food is present. Rock dust, kelp, etc, are useful considerations if necessary, the wide mineral spectrum being necessary to encourage fungi in depleted agricultural soils. Whilst there may be a few annuals and self-seeders in the mix, some of useful perennials we include are;
- Agastache foeniculum
- Armoracia rusticana
- Dryas octopetala
- Foeniculum vulgare
- Glycyrrhiza echinata
- Medicago sativa
- Origanum vulgare
- Thymus vulgaris
- Aegopodium podagraria
- Allium tuberosum
- Astragalus cicer
- Bunias orientalis
- Centranthus ruber
- Chenopodium bonus-henricus
- Diplotaxis spp.
- Dryas octopetala
- Hedysarum boreale
- Hemerocallis spp
- Lupinus spp.
- Myrrhis odorata
- Oenanthe javanica
- Origanum vulgare
- Oxyria digyna
- Petasites japonicus
- Physalis heterophylla
- Physalis longifolia
- Pycnanthemum spp
- Rheum australe
- Rumex acetosa
- Rumex acetosella
- Rumex scutatus
- Sium sisarum
- Stachys sieboldii
- Symphytum uplandicum
- Symphytum grandiflorum
- Trifolium repens
- Trifolium pratense
- Angelica sylvestris
- Perideridia gairdnerii
- Petasites japonicus
Breeding hardy nuts
A lot of nuts are borderline for us here. Chinese and American chestnut, their hybrids, butternut, Manchurian & black walnut, American, European & beaked hazel, etc, are all useful candidates but so far there are no nurseries with hardy lines suitable for any reliable commercial use in our climatic zone. Due to the big-Ag economy there is little chance of the necessary breeding being done by commercial nurseries, and so we need a lot of folks breeding out useful perennials for their areas. Based on the mass breeding of Luther Burbank we have seed arriving from different parts of the world and will be planting out nuts en masse hoping for the handful that can handle our climatic conditions. The most promising genetics for chestnut and hazel are in the US, so we will be planting out a lot of nuts from the US, Eastern Europe and Scandinavia in nursery beds hoping for that 1 in 100 that has the genetics we are after. In this video Mark Shepards offers insights into his work in this regard, and we appreciate the emphasis on taking responsibility for breeding and continuing the development of future proof food supplies.
Our NW paddock will be a savannah style planting, still following the overall Keyline layout, but with wider 14-18m spacings between trees/rows. Deciduous trees planted this way into pasture will have no detrimental effect on pasture and livestock production for at least 10 years. Forage production tends to fall off rapidly, however, once trees exceed about 35% canopy cover.
Through direct marketing to a local customer base, processing as much as possible “on farm” and value adding our products, we can make small-scale regenerative agriculture viable. Whilst the educational arm of our enterprise gives us a security some farms do not possess, our goal is to demonstrate the viability of small-scale, local, beyond-organic agricultural supported communities. We purposefully do not want to operate on any form of subsidy, as we believe that this disempowers the responsibilities of farmers / land managers. Simply by having the facility to process wood, fruit, breed plants, gather people, etc, we open the doors to community engagement and cooperation — important aspects of our design. We aim to add a nice green blop at 59°N on the map below, as a farm producing for its own needs as well as a useful and vital surplus for sale.
Benefits of silvopastural / silvoarable systems
I’ve seen alley-cropping agroforestry systems mainly planted between 8-26m around Europe. Talking to Professor Martin Wolfe about his research and observation, we decided to go with 12m spacings between our Keyline rows to optimize beneficial interactions between trees and pasture / row crops. It seems that beyond 26m the beneficial interactions tail off considerably.
Poplar over wheat, the benefits of agroforestry are diverse and numerous and could provide multiple benefits in many farm enterprises
A lot of the farms I have visited could benefit from integrating tree systems into conventional cropping / pastoral scenarios. The benefits are diverse and rich;
- Integrated tree systems can provide fodder, niche crops, spaced crop harvest, firewood / fuel, coppice yields, shelter, biomass, lumber, biomeiler material, water cleaning, pollination, habitat and riparian protection as well as utilize marginal land.
- Controlling runoff and soil erosion, thereby reducing losses of water, soil material, organic matter and nutrients.
- Maintaining soil organic matter and biological activity at levels satisfactory for soil fertility. This depends on an adequate proportion of trees in the system — normally at least 20% crown cover of trees to maintain organic matter over systems as a whole.
- Maintaining more favorable physical soil properties than conventional cropping through organic matter maintenance and the effects of tree roots.
- Help close nutrient cycles. This is true to an impressive degree for forest garden and farming systems.
- Checking the development of soil toxicities, or reduce existing toxicities — both soil acidification and salinization can be checked, and trees can be employed in the reclamation of polluted soils.
- Layered tree / perennial systems utilize solar energy more efficiently than monocultural systems — different height plants, leaf shapes and alignments all contribute.
- They can lead to reduced insect pests and associated diseases.
- Can be employed to reclaim eroded and degraded land.
- Creation of a healthy environment — interactions from agroforestry practices can enhance the soil, water, air, animal and human resources of the farm. Agroforestry practices may use only 5% of the farming land area yet account for over 50% of the biodiversity, improving wildlife habitat and harboring birds and beneficial insects which feed on crop pests. Tree biodiversity adds variety to the landscape and can improve aesthetics.
- Moderate microclimates. Shelter given by trees improves yields of nearby crops and livestock. Shade in summer can be beneficial for livestock, reducing stress.
- Agroforestry can augment soil water availability to land-use systems. In dry regions, though, competition between trees and crops can be major problem.
- Nitrogen-fixing trees and shrubs can substantially increase nitrogen inputs to agroforestry systems.
- Trees can probably increase nutrient inputs to agroforestry systems by retrieval from lower soil horizons and rock weathering. (‘Mining’ minerals and trace elements and relationships with fungi.)
- The decomposition of tree litter and prunings can substantially contribute to maintenance of soil fertility. The addition of high-quality tree prunings (i.e. high in nitrogen but which decay rapidly) leads to large increases in crop yields.
- The release of nutrients from the decomposition of tree residues can be synchronized with the requirements for nutrient uptake of associated crops. While different trees and crops will all have different requirements, and there will always be some imbalance, the addition of high-quality prunings to the soil at the time of crop planting usually leads to a good degree of synchrony between nutrient release and demand.
- In the maintenance of soil fertility under agroforestry systems, the role of roots is at least as important as that of above ground biomass.
- Agroforestry can provide a more diverse farm economy and stimulate the whole rural economy, leading to more stable farms and communities. Economic risks are reduced when systems produce multiple products.
Extensive wind breaking is often a necessary and economic design consideration
Cold winds can literally blow the profitability off livestock in a cold climate. Crops suffer pneumatic damage too. Although planting windbreaks is an investment that takes some land out of production, well-designed windbreaks have often been shown to protect the health and productivity of crops enough to make the overall return positive. Multiple produces from a windbreak can include yields such as fruit, timber, animal fodder, mulch, wildlife habitat, and other economic farm products. In our situation we have considerable shelter from the tall forests around the farm. The topography also protects us. In our unique situation we will use our rotational coppice willow (see below) as partial wind breaking that also acts as a visual screening and utilizes a marginal border zone and drainage ditch.
If wind is a problem, then the species used should be selected first for their wind tolerance and appropriateness for the site (climate, soils, etc); the products should be a secondary consideration in selecting species. Obviously trees yielding products such as fruit, food, fodder, or mulch should ideally be located in the interior or wind-sheltered rows of the windbreak for maximum protection.
Beautiful example of future- proof livestock fencing from the UK
Coming from the UK I still think we have the best hedgerow systems I have seen. The art of hedge-laying is ancient and diverse, and represents an awesome technique for livestock fencing that eventually manages itself. Our country used to be thoroughly divided up by diverse hedgerows, moderating wind and providing ample habitat for birds, reptiles and mammals. In the short term, wire fencing around our main paddocks will keep wildlife out, as well as act as security if our mobile fencing fails. In the longer term we will establish hedgerows with mixed species every 30cm and 50cm between the alternate-planted double row — a deep rip with two of the shanks on the Yeoman’s plow, simple fencing during establishment and a browse guard on each bare root plant as it goes in. Once established the trunks are cut through most of the way with a bill hook (up to 70% of the trunk) and laid. Traditionally chestnut stakes with willow woven tops were used to hold a newly laid hedge in place — chestnut lasting well in the ground. Good species for our climate include blackthorn, hawthorn, crab apple, dog rose, dogwoods, hazel, oak, ash and willow.
Around the kitchen garden we will plant willow fencing for both animal protection as well as aesthetics. The North side of the garden also warrants berry bushes in front of dwarf / semi-dwarf trees, creating a heat trap orientated at the sun for solar gain. Cold climate design is all about leveraging micro-climates, but aesthetics and functionality can easily be combined.
Willows are very fast growing, and when grown as Short Rotation Coppice (SRC) they can produce as much as 10 to 15 tons of dry wood per ha per year and often more on the better sites.
Willow is grown at different spacings for different purposes. To produce long thin rods, which are ideal for basket-making or other craft work, you can plant as close as 25cm between plants and 50cm between rows. Colorful varieties for basketry can be sought.
Prof. Martin Wolfe’s short rotation willow coppice for on- farm firewood supply, providing
constant windbreak and habitat in this alternate harvest planting, Suffolk, UK
SRC plantations are typically planted at wider spacings such as 60cm between plants and rows. They are harvested every 3 or 4 years and commonly turned into wood chips. To crop more decent size logs for home use, spacings of 1m between plants and 1.5m between rows can be used.
Pollarding, (or coppicing up high) for
To set up a five year rotation;
- Divide your area into five roughly equal size beds.
- Plant all the beds during the dormant season.
- Control weeds thoroughly in the first growing season, landscape fabric is an easy way to achieve this.
- In the 1st winter after planting, cut down the new shoots on all the willow in all five beds.
- Second winter onwards cut one bed each year to establish a 5-year rotation.
About 6500 plants on 1ha can yield around 13 tons of biomass for burning. Here in Sweden it is Salix Viminalis that is commonly grown as a commercial source of biomass. This can either be chipped and burnt or bundled into traditional faggots. A lot of farms around here have these marginal pockets and damp ditches where nothing is grown. This is a potentially fantastic yield where the stands can also be providing shelter, pollen and habitat during their rotation. Our willow rotation will only yield an estimated 1.3 tons, which will help with our firewood load as well as perform other useful beneficial functions.
The tradition of coppicing does not seem as familiar in Sweden compared to where I come from, however many trees are good for coppice; for fuel wood, furniture and crafts, charcoal, tool making, etc;
The entrance to the farm will sport 30 lime pollards, making both a grand architectural entrance as well as providing ample salad for our visitors for several months each year. Pollarded at harvest height these make excellent support for hardy kiwi, etc, which can all be pruned together when necessary.
With enough spruce and larch for all our construction / infrastructure needs one way we will manage some of the older timber is with a mobile sawmill. Timber is the number one value added product on the planet. Add desirable species to the mix of slow and carefully air dried timbers and you can make good income selling lumber to the right people. Our patch of 90 yr old Spruce is valued at 150,000 SEK (US$23,250). In planked form I estimate its value at way more than the cost of the farm! A 50,000 SEK investment for a second hand mobile sawmill will ensure our building projects are cheap and require no loans or hefty investments.
Areas for leaf-tree planting in orange. The red outline depicts overhead cabling — an area
where tall trees cannot be planted
Serious wood workers will pay serious cash –
here’s Eur 3000 worth of Tilia @Ecole
Superior d’ebenisterie, France
There are many options for sawmills, and good opportunities for secondhand models. The leaders in this field seem to be the Aussie Lucas Mill (see also here, here, and here) with both circular swing saw and slabbing options on all models. This allows for maximum recovery on saw logs and super nice wide slab options for making custom furniture, etc.Woodmizer are also a highly regarded manufacturer, although these are band saw models. They are cheaper, but will not cut such wide widths, and don’t have the same versatility as a Lucas style set-up. It’s a great investment when you have a lot of timber on the property, both for your own construction needs and for processing your own and other’s lumber. Other options include chainsaw adaptations if you don’t have much timber but want to use your own lumber for building, etc.
The patches outlined in orange above show where we will plant leaf trees into the sparse regrowth of spruce. It also makes ideal pig habitat, and we will use pigs for all the cultivation work here. They will need additional feed, but will also provide a chunk of the farm’s meat needs, with some surplus for local sale.
The area outlined in red must be kept low due to overhead power lines. This marginal area, typically unfarmed, will make further “pig pastures” with eventual plantings of high value berry fruits that should thrive well in the “edge” system. Every little niche can be utilized when space is a limiting factor in design, and that applies to farm design too. Whilst these areas are not conventionally commercially viable, our farm will concentrate on feeding itself and its visitors too.
Tree Nursery Considerations
Growing perennials is more challenging than popping in some non-dormant annuals that respond to very basic conditions. Many perennials require specific treatment to mimic natural germination and “trick” the seed into growth.
Stratification of seeds involves mixing the seed with a moist medium and keeping warm and/or cold for a certain time before sowing. Seeds are usually mixed with moist (not wet) silver sand, using 4 parts or more sand to 1 of seeds. We’ve found it best to use a mister, as it is very easy to get the mix too wet and risk rotting. The mix should be placed in a plastic bag, which can be sealed and re-opened. Label the bag well! Warm stratification means keeping the seed/sand mix at about room temperature around 15-21°C (60-70°F); cold means keeping the mix at about 5°C (40°F) — a domestic fridge being ideal for small quantities. When cold stratifying over winter, seed/sand mixes can be placed outside in a rodent/bird-proof container (eg. a plastic dustbin). Whenever stratifying seed, check every week or two to see if germination is starting. When it does you will see white roots start to emerge from seeds, and if this happens then the seeds should be sown immediately. If this isn’t possible, keep the mix at a temperature just above freezing until you can sow.
Scarification of seeds involves softening the hard seed coat in some way to allow water to be imbibed into the seed. The simplest way of achieving this is to give the seeds a hot water soak, putting them into water at about 88°C (190°F) and allowing them to stand for several hours while the water cools. Alternatively, the seeds can be very carefully rubbed between two sheets of fine sandpaper.
Dewaxing – some seeds are covered in a layer of wax which stops the seeds imbibing water and germinating. This must be removed before stratification or sowing; the best way to do this is to rub the seeds between two sheets of coarse sandpaper (do it for periods of a few seconds at a time, then check the seeds – you only want to get rid of the wax and not damage the seeds!)
Seeds which take a long time to germinate are best sown in seed trays or pots, and covered with sand rather than compost. Very small seeds should be sown on the surface of the compost and the tray/pot kept moist by enclosing it in a plastic bag. Don’t give up if seeds don’t germinate, or if only a few germinate in the first year, as many seeds spread out their germination over more than one year as a basic survival mechanism. If the seeds are large enough, you can check their viability by cutting one in half – the seed embryo inside should be white and solid, and not soft or watery.
Recommended treatments you find online / in books, etc., promote good germination. Using these treatments does not guarantee germination. Our experience is that different sources often give widely varying advice! Remember you are trying to mimic nature’s processes!
Once treated seeds are planted, either in pots or prepared open beds / cold frames, we like to use root trainers, which vary in size suitable for vegetables all the way up to 1 litre tree containers. The “books” open up for root inspection, and as you can see from the photo (left) the roots develop in a healthy manner and air prune when they come out of the bottom of the cell, meaning a tree will not “root ball”. This is critical; I like to compare root-balled trees to the old images of bound feet from China. This is injury the plant will never fully recover from, so in a long-lived organism it is critical to care for their early years well.
We also use a slow release NPK fertilizer with good compost and vermiculite or similar. Whilst this may be controversial for some, it best mimics the release of nutrients in the soil. Vegetables staying in module for a few weeks have no problem with good organic compost, however a tree or shrub that might remain in the root trainer for considerable time needs adequate nutrition, especially in the beginning of its life. Fungal inoculants, either by way of commercial products or (perhaps preferably) fungal oriented compost made from local materials will help start beneficial interactions with fungi and other soil microorganisms. A heat mat under the establishing seedlings is useful in these cold climates to help get everything off to a good start.