Trees and Forests (7m 25s)
The principle for the trees and forests chapter is to plant useful trees.
[What is a tree?]
A tree is one of the best physical representations of how nature works: It is productive, stable, self-maintaining, self-regulating, clean air-producing, water-storing, temperature-moderating, fertility-increasing organism.
From microorganisms to monkeys, trees provide habitats for all kinds of creatures. They also absorb rainwater and create transpiration. An average elm tree will evapo-transpirate up to 15,000 liters of water in one day. Here’s a good image that illustrates the multiple layers of trees.
You can plant trees in any number of ways. At the Art of Living permaculture site, we planted over 200 trees in which 90-95% of them have since survived. The planting method we used was to:
- Dig a hole, in the shape of a wok, slightly rounded at the bottom, twice as deep as the tree root base,
- Then add coconut husks, banana leaf plates or other dense organic material to the bottom of the hole to hold water,
- Then set the tree. Mix 3-4 handfuls of compost with the soil dug from the hole,
- Then cover the whole area with mulch. Avoid putting mulch directly next to the trunk,
- As mentioned in the earthworks chapter, you can dig trenches around the entire tree. Water then seeps into the ground to encourage a deep taproot.
Here’s a good image from www.DynamicScapes.com that illustrates a few planting tips.
No-till tree planting
This procedure, practiced at Sadhana Forest in India, allows tree roots to penetrate the hardpan and not disturb the existing soil ecosystem.
Greg (speaker): “So, two days ago, we came and we built this mound and this trench. The trench is to collect rainwater as well as to build our mound. As you can see here, some of these other examples. The tube sitting in the center of the mound, inside the tube is where we plant, and after the tube is built we will fill the tube completely with water, to ready the soil underneath for planting. Then, once that’s done we come here and plant this tree.
Sadhana Forest has planted over 1,000,000 trees using this technique. They are replanting a TDEF forest, Tropical Dry Evergreen Forest, which was the native species in the area some years ago.
Wick irrigation technique
One method to water trees throughout the day, also practiced at Sadhana Forest, is to turn a 2L plastic bottle into a slow-release watering system. To do this:
- First, cut a small hole for a wick on the bottom of the bottle,
- Then push a cotton wick through the hole and leave 20 centimeters around the outside of the bottle. Seal with silicone or epoxy found at a hardware store,
- Then fill the bottle with water and crack the top to let only the tiniest amount of air into the bottle. This technique could stretch 1L to last a week.
As far as selecting what trees to grow at your site. The strategy would be the same as choosing plants – first see what trees are already growing, then check with a local nursery to see what’s available and what the local people recommend, maybe order some exotic, experimental seeds online. There are only so many options you have to selecting trees.
A forest is a large area of land covered with trees or other woody vegetation. They contain 80% of the Earth’s plant biomass. Forests have many yields and can described by 7 “F”s: Food, fuel, fiber, fertilizer, fodder, pharmaceuticals (farma) and fun.
Layers of a forest
Layers of a forest also can catch and store rainwater at different elevations as the rain falls.
The top layer of a forest is the canopy layer. Typically 8-12 meters tall, canopy trees range from timber, fruit and nut trees.
The understory layer is typically 3-9 meters tall, consists young trees, and also trees that grow slowly because they don’t get enough light filtering through the canopy. Most fruit trees are in the understory layer.
The shrub layer is typically around 3 meters tall. This includes mature shrubs and bushes, medicinal and other beneficial plants.
The herbaceous layer is typically small, perennial plants. Many perennial, culinary, medicinal and other beneficial plants and herbs are in this layer.
The groundcover layer is made up of often shade-tolerant surface crops and nitrogen fixers that grow close to the ground, grow densely and fill bare patches of soil.
The vine or climbing layer spans multiple heights depending on how they grow. They are a great way to add productivity to a small space. It is important to keep them trimmed so they are easy to harvest.
The fungal layer is an entire network of communication highways, aiding in the nutrient uptake of all plant species in an emerging forest.
Tree support species, or tree guilds, provide nitrogen, shade, keep pests away and attract insects. A good tree guild will have 7 support plants for every 1 canopy tree.
Succession is the process by which an area undergoes more or less orderly and predictable growth patterns.
This stage begins with barren rock or mineral substrate. Weather breaks down the minerals of the rock. Then bacteria, lichens, algae and mosses emerge. This layer lasts thousands, even millions of years.
Once vegetation grows on the rock, the space enters secondary succession. Most places where we’ll want to plant a forest, is already in the secondary phase of succession. This phase generally involves in a similar pattern:
- Annual, perennial and herbaceous plants and grasses come to the area
- Then the shrubs, thorny, woody weeds come to protect the soil
- Then understory trees which shade the forest floor
- And finally climax trees, the hardwoods. When climax trees reach their potential, the forest is mature.
Forests take centuries to mature on their own. But, like compost, humans can accelerate this process to establish a forest in less than a decade.
A food forest is a perennial polyculture of multi-purpose plants, where most, if not all, of the species are edible or useful in some manner. As a general rule when establishing a forest, you first plant 90% legume trees and 10% fruit trees. Then about 20 years later, it will flip – you’ll have 10% legumes and 90% fruit trees.
Planting a food forest
Here are a few notes on planting a food forest:
- First, do any necessary earthworks to prepare the land to catch and store rainwater,
- Then, compost the existing brush and mulch where you plan to plant.
- Then select trees.
- It is helpful to make a sketch of the area you have to create a forest. Consider these patterns when designing your forest: You have alley-cropping… island guilds… radial patterns… scatter pattern… and intercropping, if there are already some vegetation there.
- Then plant trees.
Okay, so quick recap:
- Trees are a physical representation of the shape of nature, which is why they have survived this long on the planet.
- There are many methods used to plant trees.
- By planting multiple layers at once, we can grow a forest in 10 years, instead of 100.
Great, that’s the trees and forest chapter. Thank you for your time.