The orchard as a system

A systems ecologist sees an orchard as energy and materials moving through a few stocks: sun, rain and snow come in, soil, fungi, roots and wood hold them, and fruit, prunings and heat go out. Luke Ruffner Robinson, who owns Montana Fruit Trees, holds an MSc in Systems Ecology, and his tools come from H.T. Odum, Eugene Odum and Donella Meadows.

Draw the orchard as a system

Start with a drawing. H.T. Odum (1924 to 2002) rebuilt ecology around energy flow, and his energy systems language draws any system as sources, storages, producers and consumers inside a frame, energy flowing left to right and money the other way. One orchard block:

• Sources: sun, wind, rain and snow, soil minerals, and what we bring in (fuel, trees, tools, labor, know-how).
• Storages: soil water, soil organic matter, root and wood reserves, fruit.
• Producers: the fruit trees, pollenizer varieties included, and the understory.
• Consumers: the soil food web, bees and other pollinators, predators and pests, deer, livestock, and us.
• Feedbacks: fungi feeding roots, pollinators carrying pollen from pollenizer trees, predators knocking pests back, prunings and leaves returning to the soil.

The drawing shows how much is free. Most arrows into the frame cost nothing, snow counts as a source, and your own attention is a storage that drains.

Find the stocks that matter

A stock is anything that builds up over time, and stocks carry an orchard through bad years. Meadows called a stock "a store, a quantity of material or information that has built up over time," noted that "stocks change only slowly, never suddenly," and wrote that big stocks, relative to their flows, are more stable than small ones. So find the ones that matter and give each a cheap gauge:

Tree reserves are easy to forget. As our cold hardiness calculator page puts it, a stressed tree, or one that lost its leaves early, goes into winter with less in the tank.

Watch the feedback loops

Feedback loops decide whether an orchard builds itself up or wears itself down. Meadows: "A negative feedback loop is self-correcting; a positive feedback loop is self-reinforcing." The self-reinforcing loop we want: mulch and prunings feed soil fungi, fungi feed the tree, the tree grows, and growth makes more prunings to chip and put back. The one we avoid: a spray kills predators along with pests, the pests rebound, and you spray again. Protect the self-correcting loops too: predators, June drop, a well-buffered soil.

Meadows adds two warnings. "Delays in feedback loops are critical determinants of system behavior," and an orchard is mostly delays: years to first fruit, decades to build soil, hardiness that only shows in a test winter. And "missing feedback is one of the most common causes of system malfunction." That's our About page in systems language: reach for the bottle and you cut the loop that tells you why the pest showed up.

Aim for power, not speed or efficiency

H.T. Odum's maximum power principle is a lens, not a law, and still argued over. With physicist Richard Pinkerton, he proposed that natural systems tend to run at the efficiency that gives maximum power output, not maximum efficiency.

For an orchard, skip both extremes. Maximum efficiency is the least input per bushel. Maximum rate is growth pushed with nitrogen and water, and it burns reserves: late soft growth goes into winter less ready, and a heavy crop starves next year's flower buds. What lasts captures a lot of free energy and routes some of it back into things that capture more, like fungal partners, an open canopy and mulch.

The energy hierarchy says where your hours belong. Odum's measure of energy quality, transformity, starts at 1 for sunlight and climbs with each step up the chain to a grower's skilled hour, so spend those hours as controls (a graft, a timely thinning), not brute labor.

Judge inputs by embodied energy, not price

Price tells you what an input cost at the store, not what it took to make or what it does to the orchard's free income of sun and rain. Odum's word for what it took to make is emergy, spelled with an m for "energy memory": all the energy of one kind that went, directly and indirectly, into a product or service. The farm studies line up:

Emergy has plenty of critics and real uncertainty, so skip the math. Keep three columns instead: free and renewable (sun, rain, snow, nitrogen fixed on site), what the place is losing (soil, organic matter, groundwater), and what you buy. Then run the test that Odum's A Prosperous Way Down implies for a future with less fossil fuel: what happens to the orchard if an input doubles in price or disappears.

Use pulses on purpose

An orchard does better when you pulse it on purpose. In "Nature's pulsing paradigm" (1995), W.E., Eugene and H.T. Odum argued that nature pulses rather than settling into a steady state, and that "pulsing of medium frequency and amplitude often provides an energy subsidy for the community thus enhancing its productivity." Our medium pulses:

• Pruning. Bob Purvis lets a plum or apricot limb fruit for 3 to 4 years, then cuts it near the trunk so a new shoot takes over.
• Chop and drop. Cut comfrey and support shrubs and leave the cuttings over the roots.
• Thinning. Taking fruit off early damps the boom and bust of biennial bearing (Iowa State Extension).
• Animals. Short, heavy visits, then long rest.

Winter is the big outside pulse, and the tree's cycle has to stay coupled to it; that's what our mid-August water taper is for. Rare giant pulses hit too. In the 2026 bloom frost, one grower friend saw 15F in bloom and got no fruit at all, while at Luke's the currants and gooseberries bore heavily after their flower buds saw about 22F. A mix of crops spreads the risk.

Let the system select

The cheapest way to find trees that fit your site is to let the site pick them. Odum coined "ecological engineering" in 1962 for cases where the energy people supply "is small relative to the natural sources but sufficient to produce large effects," and a 2003 paper he co-wrote lists "maintaining biodiversity with multiple seeding" among its techniques. Mark Shepard calls his version STUN, "Sheer, Total, Utter, Neglect." His advice: "Plant a zillion seedlings and let the losers die."

That's why we grow seedlings alongside grafted trees. Our Siberian C peach seedlings carry on Miekal's selection at Driftless Sacred Grove in Wisconsin, now five generations in. For SnowCzar almond, still in trial, we froze and thawed 800 seeds during stratification, planted the 40 that came up, left the young trees in pots unprotected through a winter, and kept 8.

Three cautions: selection only works on the variation you start with, a run of mild winters selects for mild winters, and without records the sorting teaches you nothing.

Let the ground mature, but not all the way

An orchard does best when the soil and the edges grow up while the trees keep producing. Eugene Odum, H.T.'s brother, described how ecosystems change as they mature in his 1969 paper "The strategy of ecosystem development": an orderly progression toward a climax state where "maximum biomass and symbiotic function between organisms are maintained per unit energy flow." The classical predictions:

A mature system has little surplus to spare, and a harvest needs a surplus, so no orchard should go all the way. A conventional orchard holds its ground layer young on purpose, with bare or sprayed soil, soluble fertilizer and low diversity. We'd rather let the supporting parts mature (soil, understory, hedgerows, predator habitat), take the surplus as fruit, and close cycles by putting prunings and leaves back.

Change the rules, not the numbers

The rules, goals and mindset are where the power is. Donella Meadows ranked twelve places to intervene in a system, weakest to strongest, and wrote: "Parameters are dead last on my list of powerful interventions."

The no-cide rule protects the self-correcting loops at number 8, and "power over the rules is real power," Meadows wrote. The goal is an orchard that comes through the bad winter, not the biggest crop in a good one. The paradigm is feeding the soil, because "Paradigms are the sources of systems." She also warned that "NO paradigm is 'true,'" ours included, so we keep testing it. On information, she described Dutch houses where electricity use was 30 percent lower with the meter in the front hall, so hang your rain gauge where you walk every day.

Related guides

• Feed the soil, not the tree
• Why we grow seedlings alongside grafted trees
• Water for young trees in dry country

Where this comes from

• Our About page, cold hardiness calculator, rootstocks page, product notes and records.
• H.T. Odum: Environmental Accounting (1996), A Prosperous Way Down (2001, with Elisabeth C. Odum), "Nature's pulsing paradigm" (1995).
• Farm emergy studies: Martin and colleagues (2006), Lefroy and Rydberg (2003), La Rosa and colleagues (2008).
• Eugene Odum, "The strategy of ecosystem development," Science (1969).
• Donella Meadows: Thinking in Systems (2008) and her 1999 essay on places to intervene in a system.
• Mark Shepard, Restoration Agriculture; Bob Purvis's lecture notes; Iowa State University Extension.

Updated September 2026.