Edible Nitrogen Fixing Trees

I’ve been getting more into permaculture and how it can reverse desertification. Much of the world has experienced expanding deserts while losing grasslands and forests. The Great Basin has experienced desertification on a massive scale over thousands of years. The Great Basin contained one of the largest freshwater lakes in the world, surrounded by forests filled with wildlife. Lake Bonneville, as the lake is called, was bigger than many modern countries. Now all that remains is the Great Salt Lake, salt flats, deserts, and some forested mountains.

Elaeagnus Multiflora
Goumi berries (https://commons.wikimedia.org/wiki/Category:Elaeagnus_multiflora)

Halting Desertification with Permaculture

My interest in permaculture stems from my desire to heal damaged ecosystems. We can get into all kinds of arguments about what is and what is not a damaged ecosystem. I consider any ecosystem that is unfriendly to humans to be damaged. That probably stems from my belief that once Earth was more friendly to humans than it is today. I also firmly believe that through proper management, nature and humans can get along symbiotically, if humans take the initiative in healing damage and get out of the way when nature is healing itself.

I suppose there are probably limits to the permaculture-induced transformation of an area like Dove Ranch. Dove Ranch sits in a semi-arid region just above the old lakeshore of Lake Bonneville. In many areas of Dove Ranch, the top soil has eroded or become salted. Permaculture can heal both salted ground and eroded topsoil. However, growing a hillside full of sugar maples is likely out of the question. Improving the soil and growing an edible forest until I’m ready for other uses for my land is not out of the question.

After observing and studying the land, the first two steps to improving land with permaculture are, 1) the introduction of on-contour swales, and 2) planting of nitrogen-fixing trees and shrubs. The swales hug the contour or the terrain, preventing more erosion damage and other runoff-related damage by slowing the flow of rainwater. Slowing the flow of runoff also encourages healthy ground water plumes that plant life depend on during rainless weeks.

After creation of swales, the uphill side of the swales are planted with nitrogen-fixing plants. Nitrogen-fixing trees and shrubs are typically pioneer plants that can handle extreme weather and soils. They act as natural fertilizers, preparing the land to host less hardy plants. In addition to adding nitrogen to the soil, nitrogen-fixing plants also add organic material on top of the ground fostering topsoil creation. Often, pioneer plants are called invasive when introduced to ecosystems that no longer need their help. However, when placed in extreme environments, they heal damaged land.

Affording Swales and Plants

Swales present a problem for me. I don’t have the equipment or time to dig proper swales over my 80 acres. Contour-hugging swales could add up to many, many miles of ditches I’d have to dig by hand. If you want to get a feel for what it would be like to do even a small swale in virgin soil, try taking a digging fork to a section of lawn and prepare it for a garden. After creating just a five-foot by five-foot garden your whole body will ache. You’ll also have a new found respect for any farming ancestors in your family tree.

Swales are mostly not going to happen, for now. So, I’m skipping to number two on the list—nitrogen-fixing plants. I can’t afford regular planting of pre-grown trees and shrubs. That would be pricy, require watering to get them established, and probably get eaten by rabbits or cattle before they grew very large. I know all this through two years of painful experimentation.

What I can afford, monetarily and time-wise, is planting from seed. Planting from seed is cheap enough that I can literally plant 1000’s of seeds for the price of planting one or two pre-grown trees. When you plant thousands of seeds, you can let nature help by naturally selecting the seeds that are genetically fit for your land. Instead of forcing a few select potted plants to grow where they don’t want to, you can let nature select the plants that will grow without aid.

In regular permaculture, any pioneering tree or shrub that fixes nitrogen is considered for the first stage of planting after creation of swales. Edible plants are introduced after the nitrogen fixing plants. I decided to combine these two steps and only consider drought-tolerant, nitrogen-fixing trees and shrubs that also bear edible fruits or edible legumes.

Protecting the Trees and Shrubs

You can’t just stick seeds in the ground at Dove Ranch and expect them to survive the harsh weather and grazing animals. I’ve spent some of my last two years on Dove Ranch learning where grasses, clovers, dandelions, and other plants grow successfully.

Any edible plant establishing itself on the ranch requires protection. They tend to grow near the trunk of thorny brush. Rabbits and cattle don’t seem interested in risking a prick to the nose, even for the most tasty plants. In addition, brush provides protection from the weather until the plants are established.

Edible, Drought-Tolerent, Nitrogen-Fixing, Pioneer Plants

Keeping the semi-arid environment, edible, and nitrogen-fixing requirements in mind, here are the trees and shrubs I think might survive up at the ranch. I have relied heavily on pfaf.org.  They had a great site for tracking down plants for edible landscapes. Unfortunately, the site seems to have disappeared.

Goumi or Cherry silverberry (Elaeagnus multiflora)

The goumi is drought tolerant and fixes nitrogen like the other trees and shrubs on this list. The fruit ripens  in July. I know less about the goumi than the other plants in this list. I’m not 100% sure it can handle Dove Ranch, but I’m willing to let it try.

Autumn Olive (Elaeagnus umbellata)

This large shrub, or small tree, ranges from Japan to the Himalayas. The red berries ripen in late November. It hates shade and loves dry soil. It may find a place it likes up at the ranch.

Seaberry – Sea Buckthorn (Hippophae rhamnoides)

Seaberries are found all over the world, and famously grow in the Himalayas. The fruit can easily last over the winter (sometimes on the branches) when it dries. If you follow my blog, you might remember that I’ve already sown some seaberry seeds. I’m planning to sow more now that I have a better understanding how to get them to survive.

Siberian Pea Shrub (Caragana arborescens)

The pea shrub produces legumes. It flowers in May and the seeds ripen by September. All through that period, you can eat flowers, pods, or peas from the bushes. The flowers, young pea pods, and peas are edible. We’re not talking a great taster, as it is pretty bland, but it works well when served with the right spices.

Oleaster (Elaeagnus angustifolia)

Oleaster fixes nitrogen. It is very drought tollerant. And most importantly, the fruit and seed are edible. The fruit ripens in the fall, and must be fully ripe before eating, or tastes awful.

Sowing Tree Seeds

I’ll look into planting those tree seeds as early as I can in the spring. With any luck some of them will get started this year.

I’m also planning to sow some more Colorado Pinyons. I’ve had some success with them in the past two years. They don’t fix nitrogen, but they’re Christmas trees, so I can’t get enough of them.

In the past, I’ve also sown or planted hackberries and Utah serviceberries. I may plant more of those in the future, but I don’t believe either of those are nitrogen-fixing, and they definitely don’t have the wow-factor of Christmas trees, so they’ll have to wait.

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