In drylands there is a noticeable lack of trees. This situation is kind of a Catch-22. The hotter and drier it is, the less water there is in the ground to provide for plants that can attain height, and the more the leaves of the existing trees must adapt (become smaller) to prevent transpiration and sunburn. Yet the very lack of trees and their extensive root systems, and the shade and habitat they create, and the transpiration that allows humidity to keep the air moist for pollen to survive, is one of the causes of desertification.
So how do we stop this cycle?
First, work on a manageable area. If you have a large property, then start on the area closest to your home or where you need water the most, or where water settles. As in the Annie Lamont title, Bird by Bird, you work on a piece a little at a time.
- Put in earthworks to harvest rainwater. Simple swales or rain catchment basins, perpendicular to the water flow and on contour with your property, will harvest hundreds of gallons of water each rain. You can do them with tractors, you can do them with shovels, you can do small ones with trowels above small plants. Just do them.
- Bury organic matter: hugelkultur. Do you have old wood laying around? Palm trees that are growing and being a fire hazard? Old untreated lumber full of nails? Branches? All of this can be layered into the ground. Bury organic matter downhill from your swales. If you cannot bury, then pound sticks vertically into the ground. The important thing is that you are adding organic material back into your depleted soil. It will hold rainwater, it will activate soil microbes and fungi, it will open oxygen and nutrient channels, it will sequester carbon and make it available to the plants. Our soil is mostly just dead dirt. By layering organic material with dirt you are doing what nature does, but at an accelerated pace. If your soil is unmanageable, or you can’t dig, then layer on top of the soil. Its called, among other things, lasagne gardening. Lay out newspaper, top it with fresh grass clippings or other greens, top that with dried grass clippings, dried leaves or other ‘brown’ materials, and depending upon what you want to plant in this, you can top it with mulch or with a layer of good compost and then mulch. Then plant in it! You create soil on top of the ground.
- Mulch and sheet mulch! Protect your soil from the heat and wind, and from pounding rain. A thin layer of bark will actually heat up and accelerate the evaporation process: add several inches of mulch to the ground. Better yet, sheet mulch by laying cardboard and/or newspaper directly on top of the weeds and layering an inch or more of mulch on top. This can be free mulch from landscapers, old weeds, grass clippings, animal bedding, softwood cuttings… just cover the soil to keep it moist and protected. Thick mulching alone will help keep some humidity in the air and begin soil processes, as well as reduce evaporation by reflected heat that comes from bare earth or gravel.
- Plant native plants. They thrive in our soil. Grow trees that filter the sun and don’t like a lot of water, such as palo verde, or those that take minimal additional water such as desert willow, California redbud, valley oak, or others. Grow tall bushes such as toyon, lemonadeberry, sugarbush, quailbush, ceanothusor others. Use these wonderful plants to invite in birds,butterflies, lizards and other wildlife that will begin pollination and help activate the soil.
- Design your garden for what you want to grow besides natives. Fruit trees? Vegetables? Ornamentals? They can be arranged in your mulched area in guilds to grow cooperatively.
- Grow shade. Fast-growing trees and shrubs are invaluable for protecting – ‘nurserying in’ – less hardy plants. Acacia and cassia are both nitrogen-fixers and will grow quickly to shade your plants, can be cut for green waste in the fall and also attract pollinators. Moringa is completely edible and is also an excellent chop-and-drop tree. There are many others. You need to protect what you plant from the harsh summer sunlight, and using sacrificial trees and shrubs is the most productive way to do it.
- Protect your tree trunks from scorching by growing light vines up them, such as beans or small squash.
Once you have done this process in one area, then move on to the next, like a patchwork quilt. These areas should all be planted in accordance with a larger plan that covers your entire property, so that you plant what you want in the best possible place. However, the earthworks, hugelkultur and mulching can be done everywhere. By following these guidelines, and working one small area at a time, you’ll have success, have trees, shade, food and be helping reverse desertification, one plot at a time.