An orchard from a single tree

At some point in your childhood, I hope, you ate an apple and hit upon the idea of planting the seeds. Most such experiments stop at the paper-cup stage, but if your tree survived long enough to bear fruit, you probably noticed something strange: the seeds from that Golden Delicious apple do not necessarily grow into a Golden Delicious apple tree.

Seeds, you see, come from pollinated flowers. Flowers exist to get animals to combine a plant’s DNA with that of another plant, just as fruit exist to persuade animals to eat them and drop the seeds and fertiliser somewhere else. An apple’s fruit, obviously, is determined by what kind of apple tree it is, but the seeds inside are shaped by whatever pollen came to the flower.

If the bee that pollinated that Golden Delicious tree, way back when, had been to a crab-apple tree just before, then that Golden Delicious apple contains seeds that are part crab-apple. And since there are so many wild and domesticated apples around us, and bees need to make their appointed rounds, it’s quite difficult to grow purebred apples – and many other fruits – from seeds.

Even if you succeed in growing the fruit you want, it doesn’t necessarily come on the tree you want. You want a certain size of tree, suited for your climate and resistant to disease. With fruits you want a certain size, variety and flavour, and the two don’t often come in the same package.

Each plant variety has strengths and limitations that other varieties do not, just as a golden retriever dog has advantages and limitations that their wild wolf cousins do not. Of course, you can’t simply cut off a dog’s head and plant it onto the body of a wolf, getting a healthy but friendly Franken-dog. With trees, though, you can do exactly that.

It’s called grafting, and it dates back to ancient times, and today is practiced on a vast commercial scale; when you eat fruit, it was almost certainly from a grafted tree.

If you want to graft a tree the wrong way, do what I did the first time: let the knife slip the wrong way, cut your thumb almost in half, and spend a night in the emergency room. Grafting knives are quite sharp, so be careful.

To graft a tree the right way, however, you take a root and stem of one kind of tree for your “stock,” the base of your Franken-tree. You could use a hardy wild variety of crab-apple, or more commonly these days, one of many varieties bred just to be root-stock for grafts. The stock determines what the size and shape of the tree will be – if you use the bottom of a dwarf tree sapling as your stock, you will end up with a dwarf-sized tree.

Then you take a 1-year-old cutting, from the previous year’s growth, for your “scion” – again, a Golden Delicious scion if you want Golden Delicious fruit. The best scions are straight, long, upright shoots, usually taken from young and vigorous trees; in old trees this type of growth is hard to find and usually near the top.

The tree that grows from a successful graft will have the best of both worlds; for example, as the size and shape of your root-stock variety, but yielding the fruit from your scion variety.

Apples are the fruit most commonly grafted, but you can graft pears, plums, cherries or many other fruit. Amazingly, you can even interchange certain species – stone fruit like plums, cherries and peaches are interchangeable, and you could, in theory, attach them all to one “fruit cocktail” tree. The good people at Seed Savers, County Clare, Ireland, even grow pears from their hawthorn tree.

Nor do the possibilities stop at trees; I am told you can even graft the top of a tomato plant onto the bottom of a potato plant – they are both in the nightshade family – and get both vegetables from the same organism.

Nor are you limited to one scion; in theory, you can attach as many scions as your root-stock tree has branches. You can even attach multiple kinds of apple; one man in Britain has grown a single tree, planted 25 years ago, and attached 250 separate scions onto it, making it the only tree in the world to yield that many kinds of fruit.

It’s best to graft in winter or spring, when the trees are as dormant as possible – the people at Seed Savers say they cut scions in December, store them in sand in cool dry place, and graft them in February or March. To try grafting you need the following things:

• A scion, or a small branch from tree whose fruit you desire;
  
• A root-stock, or sapling of the same fruit, but hardier and wilder – say, crab-apples if you’re grafting apples;
  
• A very sharp knife (again, be careful);
  
• Bandages or grafting tape;
  
• A candle and matches (optional).
  

To graft a branch, you have to cut the scion off the desirable-fruit tree, and cut a branch of similar diameter off the hardy stock tree. If you’re trying this for the first time, the best thing might be to use a sapling, 6 months to 1 year old, as the stock, and the scion can be grafted onto its stem and become its top half.

Make a very slanted, diagonal cut at the top end of the stock, so that a long strip of bark is exposed. Then, rotate the sapling to the other side and cut it in the other direction, making an upside-down V shape. Finally, take the scion and make a similar cut the other way, so that the two dove-tail together. There are many other cuts that could be used, but this is one of the simplest.

The idea here is to expose as much of the cambium – the green layer under the bark – as possible, and to lay the stock’s and scion’s cambium touching each other. That’s the living part of the tree, where healing takes place, and that’s the part that will grow back together. The experts I talked to also recommend cutting off the tip of the scion after grafting, anything more than three buds up, so the tree will concentrate its growth into the most viable section.

Fit the two as tightly and perfectly as you can, and then make sure they stay together. Some people take sticks of wood and lay them against the dove-tailed branches to keep them in place. In any case, wrap the entire thing together in bandages or grafting tape. What you’ve done, effectively, is make a splint for the tree to grow back just as broken bones would.

Finally, light the candle – you were wondering what that was for, didn’t you? – and drip wax onto the wrapped bandages until the entire thing is sealed away from bacteria and fungus. This is an optional step, though – some grafters preferring to simply wrap the stems together or use sealing paste like Lac Balsam, which does not need to be heated. If you do use wax, use it sparingly, lest the heat damage the tissues.

If you want to try grafting yourself, it’s best to take a course or talk to an expert first, or at least look at a lot more detailed information in books and the Internet; gardening centres around you might have courses available. Once you get it right, though, you can start experimenting with turning a single tree into an orchard.

A bridge to the technosphere

For half the Irish year I ride my bicycle along the canal in the morning to the village where I pick up the bus to my job in the city, and ride back again in the evenings. The morning ride gives me a chance to see the landscape when the sun is still drying the leaves of dew and shooing away the clouds of mist from the bog, when the fish are beginning to stir in the clear waters below and the herons are shaking off sleep on their perches.

Similar patterns stretch across the land, the water and the sky. The dendritic patters of the tree branches of the trees that line the road resemble the tributaries of the streams that flow below them, with tiny streams feeding larger ones and then joining others, feeding the fields of wildflowers. They resemble the veins of my hands, more visible now than they used to be as I grow older. They resemble the mycelium I see in our compost, which I tried to disturb as little as possible today when I spread it across our new garden bed.

As Albert Bates put it in the permaculture course, we see the same patterns across all scales – the shape raindrops take on leaves of grass are governed by the same laws that draw matter into stars and stars into galaxies. The tessellating pattern of water as it twists and curls around rocks in the stream, resemble the mist curling and twisting as it floats away, purged by the light of the dawn, or the patterns of clouds as they ripple over the Irish landscape.

The morning ride shows me the patterns of the farmers who live near me, before they are outside at work. I see that Liam mended the fence where the calf broke through, that last night’s wind blew some trees over the phone lines, and that Liam won’t be reachable by phone this week. I see that Mick’s family have laid flowers on the cross they placed along the canal, on the spot where his car went off the road last year, drowning him. His girls are only teenagers, and I suspect most people still leave his old space empty in church, his seat empty at the pub.

The ride home, likewise, gives me a chance to see my neighbours as they are busy on their plots of land. I usually see my neighbour Seamus, in his eighties and still planting his own field, and Martin, proudly showing his young cows and antique cars. I see other neighbours who never took to the car culture, and still ride bicycles or even horse-carts into the village and back.

You see, once I step on the bus to the city, the world changes. I spend three hours on a bus and nine more in an office, staring at screens, sitting in seats and dealing with the carrots and sticks of human hierarchies. I live, as most of us do out of necessity, in what Dmitri Orlov calls the Technosphere, the world of user names and passwords, computer screens and electronic noises, online profiles and digital icons.

I try to ignore the flash and flicker of advertising on the walls of cafes, office lobbies, buses, trains, cars, bicycle racks, bus stop shelters and toilets. I wear earbuds to muffle the piped-in soundtrack of advertisements, talk radio, and pop songs broadcasted into buses, restaurants, and offices. Out of necessity, I deal with the conceptual hierarchy that humans have created -- software programs, paycheque numbers and manager titles -- and pretend they represent reality.

I understand the need to visit the Technosphere, and it has its uses -- look at you, reading this on a blog. In living my life and raising a daughter, though, I always try to keep one foot in that artificial world and one foot in the real one, the one that has been here for uncounted lifetimes before us and will continue long after the Technosphere has passed into legend.  

Use plants to clean up toxic waste

Thanks, everyone, for being patient while posting is slow this summer. I have a lot going on...

In the last couple of centuries, humans have done a strange thing: We’ve dug the biggest pits, the deepest holes, and the longest tunnels the world has ever seen, all to find the most insidious and subtle poisons known to our mammalian bodies, remove them from deep inside rocks where they had lain sequestered for eons, and concentrate them in the places where most of us live. We’re starting to think this maybe wasn’t a good idea.

Take lead, which last-century humans put into containers, car parts, pipes, paints and many other products – and even in petroleum, spreading lead-tainted exhaust across the world. Lead causes brain damage and erratic behavior if absorbed into the human body, and its rise and fall correlates with the U.S. crime rate in the 20th century – the more lead was around children, the more crime appeared a generation later. It’s been banned from paints and auto fuel, of course, but it lingers on old buildings and in soil.

Or take mercury: Burning coal releases it into air and water, and thence into animals like fish – a 2009 study by the U.S. Geological Survey tested 300 streams across the United States and found that every fish tested contained mercury, a quarter at unsafe levels.

You could go on with a list of such heavy metals – cadmium, zinc, copper – right down the periodic table. Most of all, we have pulled out coal and oil and used it not just to fuel up the car and turn on the lights, but to generate hundreds of thousands of petrochemicals with unpronounceable names as long as sentences and often-unpleasant effects.

I say “we,” of course, but this isn’t a guilt trip; most of this was before your time, and you didn’t vote for it anyway. You and I use small amounts of heavy metals and fossil fuels in our own lives – driving, flying, heating, buying plastic products, just looking at this on a computer – but it’s very difficult to avoid doing so and still living in the modern world.

The consequence of so many people doing so many of these things, though, is that any urban area – and many rural ones – will have splotches on the map with large quantities of toxic materials in the ground. If you live where a gasoline station used to be, or a factory, a garbage dump, or any number of other things, you might have things in your soil you don’t want in your stroganof.

If you think you just won’t live in places, or just move away from them, congratulations: You’re thinking the same thing as everyone else. That presents a problem, as everyone who can live somewhere else will do so, and everyone who can’t live somewhere else will live on contaminated sites. Realistically, this means the poor, the elderly and other vulnerable people have to live with everyone else’s toxic waste – which is often the case already.

Other methods, like removing tonnes of contaminated soil, involve years of work and vast sums of money we don’t have anymore. If you could remove all the affected soil, moreover, where would you put it, aside from somewhere else that would then be contaminated?

What we need is a device that can suck toxins out of the soil and either turn them into something harmless, or concentrate them in something removable. No one has much money lying around to invent such a device, though, much less to manufacture millions of them and send them to sites around the world for free. Thus, these hypothetical devices would be even better if they already appeared around the world, or were lightweight and easily transportable.

It would be best, in fact, if these machines cost nothing to create, and once created could make more of themselves, at an exponential rate. While we’re at it, it would also be nice if the devices also prevented soil erosion, fed bees and other pollinators, and provided shade, beauty, a home for wildlife, and possibly firewood.

Thankfully, we have these machines now. Certain plants, it turns out, have a particular gift for sucking up specific chemicals, either as a quirk of their biology or as a way to make themselves poisonous and avoid being eaten. When these plants are sown on contaminated ground, they absorb the contaminants into their tissues, gradually reducing the amount in the soil until it is safe for humans.

Called phyto-remediation, this process has become one of the newest and most promising fields of biology. Similar methods use mushrooms in what is called myco-remediation, or use bacteria and have unfortunate names like bio-sparging, bio-slurping and bio-venting, but we’ll restrict ourselves here to plants.

The basic method is straightforward: Find out what toxins lurk in your patch of ground, and come up with a regimen of plants appropriate for the climate that hyper-accumulate those particular toxins. “Toxins,” of course, covers a lot of ground, and the vagueness of the word allows it to be used in all kinds of unproductive ways – for example, every fake New Age cure that claims to rid your body of unspecified “toxins.” So to get more specific, let’s separate toxins into two of the most common categories: metals and petrochemicals.

Petrochemicals generally have familiar atoms like carbon, hydrogen and oxygen, the same things that make up chocolate sundaes, flower gardens, testosterone, newspaper, and most of the world around us. Those same elements in different combinations, however, make common but un-tasty compounds like gasoline, or lethal poisons like Agent Orange – it’s all in how many atoms are put together in what arrangement.

If a plant can absorb, let’s say, the cancer-causing benzo-pyrene – C20H12, found in coal tar – with some oxygen (O) and then separate it into C12H22O11 and H2O, the petroleum-based poison would become sugar water. I’m not saying this is the actual chemical process, by the way – just an example of how chemical combinations can make something deadly or delicious.

When the toxins are metals, of course, they cannot be broken down into other elements any more than lead could be changed to gold. Some plants can absorb the metal and metabolise it into some kind of molecule, however, making it less easy to be absorbed by the human body and thus safer to be around. Sometimes the metals can even help us; some biologists have even proposed using certain edible plants to accumulate zinc from contaminated soils and feeding the plants to people with a zinc deficiency.

After the plants are harvested with the metals concentrated in their tissues, they can be burned, and the metal stays in the ash – a small amount of space and weight to dispose of, compared to the tonnes of contaminated earth. The ash might even be able to be mined for the metals, for complete recycling.

 One example comes from Brazil, where abandoned gold mines are leaking mercury and other heavy metals into the soil and water. Mercury is one of the most toxic of heavy metals, and once in the soil it is soaked up by grass, which is eaten by cows, which are eaten by … you get the idea. Farmers are now growing maize and canola plants in the area, though, which soak up heavy metals quite nicely – gold as well as mercury. One scientist overseeing the project estimated farmers could get a kilogram of gold per hectare from doing this, which would help pay for the clean-up.

Mustard greens were used to remove 45 percent of the excess lead from a yard in Boston to ensure the safety of children who play there. Pumpkin vines were used to clean up an old Magic Marker factory site in Trenton, New Jersey, while Alpine pennycress helped clean up abandoned mines in Britain. Hydroponically grown sunflowers were used to absorb radioactive metals near the Chernobyl nuclear site in the Ukraine as well as a uranium plant in Ohio.

Blue Sheep fescue helps clean up lead, as do water ferns and members of the cabbage family. Smooth water hyssop takes up copper and mercury, while water hyacinths suck up mercury, lead, cadmium, zinc, cesium, strontium-90, uranium and various pesticides. Sunflowers slurp a wide range of compounds – not just the uranium and strontium-90 from radioactive sites, but also cesium, methyl bromide and many more. Bladder campion accumulates zinc and copper, while Indian mustard greens concentrate selenium, sulphur, lead, chromium, cadmium, nickel, zinc, and copper.

Perhaps the most magnificent hyperaccumulator, though, is the simple willow tree, Salix viminalis; it slurps up copper, zinc, cadmium, selenium, silver, chromium, uranium, petrochemicals and many others. Also, once its biomass has concentrated the heavy metals, it can be harvested and used for many practical things.

Of course, phytoremediation operates under certain limitations; the plants have to be able to grow in that climate, and should not be an invasive species that will take over the landscape, as kudzu did in the American South. The plants can only remove toxins as deep as their roots, so the technique might not solve groundwater contamination.

Most importantly, plants move at a different speed than we do, and even after the plants are harvested they are not likely to have eliminated the toxin. Reducing a toxin to safe levels takes time, and phytoremediation doesn’t remove a problem overnight.

Perhaps the most appealing aspect of this new field, though, is its scale, that the work to clean up toxic-waste sites could be done with no massive government project or corporate funding, with no bulldozers or construction equipment, without advanced and delicate technology beyond that to measure the toxin levels. The principles could be taught to every schoolchild or practiced by every land-owner, so that if anyone detects a certain toxin on their property, they will know what to plant to gradually remove it.

The seeds and plants could be sold by any gardening or farm-supply store, so that some of our society’s most grandiose mistakes can be fixed by ordinary people, using natural means, using home-made experiments, hard work and patience, to restore our land to what it once was.

Thanks to Dr. David Leung of the University of Canterbury, New Zealand, for his assistance in checking this article.Originally published in Grit magazine.

Sources: 

Survey of U.S. streams: “Mercury Found in Every Fish Tested, Scientists Say,” New York Times, August 19, 2009.
Effects of lead on crime: “America's Real Criminal Element: Lead,” Mother Jones magazine, January 2013
Effects of lead on crime: “How Lead Exposure Relates to Temporal Changes in IQ, Violent Crime, and Unwed Pregnancy,” Rick Nevin, Environmental Research, Volume 83, Issue 1, May 2000, Pages 1-22.
Effects of lead on crime: “Hazards of heavy metal contamination,” British Medical Bulletin, Volume 68, Issue 1, p. 167-182
Phytoremedation: Recent Advances Toward Improved Phytoremediation of Heavy Metal Pollution, Bentham Books, 2013.
Gold Mines and Mercury: Phytoremediation of Mercury-Contaminated Mine Wastes, Fabio Netto Moreno, Massey University 2004.
Playground in Boston: “New Jersey company cultivates pollution-eating plants Mustard greens, alfalfa help to clean up ravages of industry,” Baltimore Sun, March 30, 1997.
Playground in Boston: Blaylock, M.J., S. Dushenkov, D. Page, G. Montes, D. Vasudev, and Y. Kapulnik. "Phytoremediation of a Pb-contaminated brownfield site in New Jersey." (1996), pp. 497-498. In Emerging Technologies in Hazardous Waste Management VIII, 1996 Extended Abstracts for the Special Symposium, Birmingham, Alabama, Industrial & Engineering Chemistry Division, American Chemical Society, September 9-11, 1996.
"Blue Sheep Fescue: Phytoremediation: A Green Technology to Remove Environmental Pollutants," p. 71-86, American Journal of Climate Change 2013.
“Metal armour protects plants from disease,” Planet Earth Online, 10 September 2010.
“Improving Plants for Zinc Acquisition,” Prachy Dixit and Susan Eapen, Bioremediation Technology: Recent Advances, M. H. Fulekar, Springer, 2010.
Bio-remediation and Bio-fortification: Two Sides of One Coin, by X. Yin and L. Yuan, Springer 2012.