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 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 & Hedges, Timber, Coppice Firewood and Tree Nursery considerations.
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 & proposed developments of Keyline landscapes.
The riparian zones protect the 2 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.
We can use these niches for cropping of fruit, nuts & timber as well as various shrub & herb layers. Occasional grazing and ideal sites for bee- hives make this a multi- functional and productive zone. Additional species we will plant in include;
· Walnut (var.)
· Hawthorn (var.)
· Hardy Grape
· Hardy Kiwi
· Sea Buckthorn
· Service berry
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.
This is where innovative use of equipment and allowing the geometry of our topography 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. For 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 spacing’s 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.
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 & 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 & shrub crops are planted as bareroots/ modules on regular spacing’s. In the Back field there are 2 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;
As with any design work, the mapping & 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 spacing’s 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
Hazel (bush) 390
J. Quince 50
Blue Honeysuckle 150
Eleagnus (Nitrogen Fixer)
Siberian Pea Shrub (Nitrogen Fixer)
Sea Buckthorn (Driveway Planting) 360 (approx. 36 Male)
(2m spacing’s with 6m between rows)
Differing planting patterns & assemblies will be used, but for a general picture we plan 7.5m spacing’s 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 spacing’s 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 under sown 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 & 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;
A lot of nuts are borderline for us here. Chinese & 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 stick 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 falls 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 it’s own needs as well as a useful and vital surplus for sale.
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 beyond 26m the beneficial interactions tail off considerably.
· 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 & 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 & 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 weathering rock. ('Mining' minerals and trace elements & relationship with fungi)
· The decomposition of tree litter and pruning's can substantially contribute to maintenance of soil fertility. The addition of high-quality tree pruning's (ie 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 pruning's 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.
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.
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.
Willow is grown at different spacing’s for different purposes. To produce long thin rods, which are ideal for basket- making or other craftwork you can plant as close as 25cm between plants and 50cm between rows. Colorful varieties for basketry can be sought.
SRC plantations are typically planted at wider spacing’s such as 60cm between plants and rows. They are harvested every 3 or 4 years and commonly turned into woodchips. To crop more decent size logs for home use spacing’s of 1m between plants and 1.5m between rows can be used.
To set up a 5 year rotation;
• Divide your area into 5 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 5 beds.
• 2nd winter onwards cut 1 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 seems less familiar in Sweden compared to where I come from, or definitely nowadays, however many trees are good for coppice; for fuel wood, furniture & crafts, charcoal, tool making, etc;
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 “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 it’s 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 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 NATUREs processes!