Farming Like a Savannah
Mark Shepard is an iconoclastic farmer and author of a number of books on regenerative agriculture. He runs New Forest Farm, a 106-acre “perennial agricultural savannah.” The farm is a planned conversion from a typical row-crop and grain operation into a commercial-scale, perennial agricultural ecosystem using oak savannah and successional eastern woodland brush-land as its ecological models. New Forest is entirely solar and wind-powered, and its farm equipment is driven by locally produced biofuels.
Bioneers’ Arty Mangan spoke to Mark about his unique farming philosophy.
ARTY MANGAN: Historically, farming has radically changed the natural environment — clearing forests or plowing prairies — and has often been antagonistic to nature and destructive to ecosystems. How can ecosystem succession be used as a guide for designing productive farms in a way that heals land that has been abused?
MARK SHEPARD: When you start with an ecologically disturbed site, you need to first work to increase the species diversity there, and the thickness, depth and fertility of the soil, until it hits a middle phase, which is when you achieve 30 to 60% canopy cover, which is the savannah phase. If it’s in a brittle environment where there are too many tree species too close together, they will compete for all the surface moisture, and they’ll suck it dry, and it will go into a system collapse, and will diverge into a scrub chaparral landscape — welcome to California. If there’s enough humidity, it will evolve into a closed canopy forest in which you lose much of the green understory, and it ends up like Pacific Northwest.
The highest photosynthetic flux (how much light actually penetrates to the crops) happens in the savannah phase. There’s more total biomass in an old growth redwood forest, but there’s not as much photosynthetic flux. If we want to keep the ecosystem in that middle, savannah phase, as I do, we have to manage our light and water levels carefully, or big wide-spreading, sprawling oaks, will start to shade out the ground and all the grass will die underneath.
So, the trees need to be pruned regularly. The result is that we get valuable saw timber and we let more light come through. Then, as we get to a point at which the grass gets shaded out and we start to lose it, it’s time to move trees. At that stage, we’ve created a resource base: a timber industry where there wasn’t one before.
If we don’t harvest the trees, the system goes to the “canopy closure” phase and we lose grass, which means we’re going to have fewer beef cows, which are part of my income. I want to make sure I’ve got 100% grass on my 110 acres, so I’ve got to remove material. I go through with a chainsaw and cut the excess trees into mushroom logs and firewood. The smaller material I lay down on the path and chip.
But the timing when I chip has to be strategic. Chestnuts in Wisconsin, for example, will ripen between the middle of September and middle of October. Around August, I put chips down in close contact to the ground and put mushroom spawn on them. The timing is important to make sure that the chips break down and provide a fertilizer release right when the tree needs to ripen the chestnut crop. We time the litter deposition phase of chipped branches with the nutrient needs of the trees.
I strive to have as few entries into a particular plot as possible. I only enter to harvest something: hay or mushrooms or cut flowers or firewood.
ARTY: When you harvest material, you’re removing carbon and other nutrients. What’s the replacement regime for the nutrients embedded in the material that you harvest?
MARK: It’s an act of healthy biological soil life. The fungi help dissolve the bedrock. That’s where the minerals are coming from, and the Sun provides energy for the whole system. The solar energy is stored in the carbon that then decays, and the decay cycle in turn helps mineralize the soil. The more amped up your decay cycle is, the faster the bedrock will release minerals What we’re doing is slowly, biologically dissolving the Earth’s crust, but we’ve got a lot of crust to go before we hit the bottom.
ARTY: But geological time doesn’t necessarily coincide with agricultural timelines and the needs of production.
MARK: If you plant a polyculture, you can get an immediate cash flow. If a farmer has grass and cows, he can plant raspberries and blackberries next year. The year after that, currants and grapes. It ends up being additive. The big problem is he’s got to add enough of those to make it economically worthwhile.
The secret is that you don’t treat a polyculture system the same way you would growing one crop. Polycultures are more of a natural system. You have to take more of a minimal approach to each crop. If you are moving a fence and a branch from a nut or fruit tree hits you, just cut it with the pruners and throw it down. Minimize your labor input.
ARTY: You take a systems approach to farming but have unexpected changes in land and climate conditions ever forced you to change your plans?
MARK: That’s something I’m learning about as I go. I’ve only been doing this on this particular property in Wisconsin for 20 years. I’m new at managing an ecosystem this way.