Unlike other methods of growing food, in permaculture, we try to understand the natural order of things and do our best to mimic it. While different fruit and nut trees have different behaviours, many of them—apple, pear, peach, chestnut, oak, pecan, etc.—are deciduous trees and operate under a similar guise. Therefore, understanding the basic annual cycle of these types of trees is important for anyone looking to practice permaculture and, specifically, grow a food forest. That goes double for those of who live in temperate climates, where the swings are much more notable.
What Is A Deciduous Tree?
In the simplest terms, trees tend to fall in two categories, deciduous and evergreen.
Evergreen trees—pine, spruce, fir, cedar, cypress—hold onto green leaves throughout the year, including winter. But, they do shed, too. There are some evergreen fruit trees, such as avocado, mango, lychee, olive, and citrus, that hold onto the majority of their leaves year-round, but these tend to be native to warmer environs. The same can be said for nut trees like macadamia and cashew. Smaller varieties of some of these species can be grown indoors in temperate climates, but to have a diverse selection of them would require a huge temperature-controlled greenhouse and all the energy, both human and otherwise, to produce a notable harvest.
On the other hand, deciduous shed all of their leaves ever autumn, and they produce a new canopy in the spring. Most common fruit and nut trees in the temperate climate are deciduous. Obviously, for those of us living in temperate climates, outside of Mediterranean zone, these are going to be our bread-and-butter fodder for cultivating food forests. Luckily, we have a huge selection, and the better we can understand what is happening with these trees at each stage of the year will only increase our ability to care for them.
A Year In The Life Of A Deciduous Tree
In the temperate climate, to varying degrees, we get to enjoy four distinct seasons: winter, spring, summer, and fall. We as humans adjust to the changes in temperature and weather, and our deciduous trees do the same. That’s why we get to enjoy the autumn leaves changing colour, get excited when things go green in spring, and celebrate the vibrancy of fruits and nuts developing through the summer. The trees use the seasonal distinctions as signals for how to behave. In the wet-dry tropics, a similar change occurs, but to a lesser extent, when wet season shifts to dry season.
During autumn, as the temperature drops and the hours of daylight decrease, deciduous trees react by dropping their leaves, a process called abscission. During winter, these trees are in a state of dormancy, their canopies bare, and they are essential in a sort of botanical hibernation, conserving energy until conditions are better suited for growth. In spring, with temperatures rising and daylight hours increasing, they develop new, green leaves. Throughout the summer, deciduous trees enjoy a full canopy, soaking up plenty of sunlight for photosynthesis and moisture. Autumn rolls around again, and the cycle repeats.
Different trees time these changes differently, some developing leaves sooner and shedding them later, but in essence, they are all undergoing a similar physiological change. As cultivators, working to make food-bearing trees realise their fullest, natural production, it behooves us to understand what is happening, why it is happening, and how we can best time our involvement so that the trees get the most from us, as we hope to get the most from them.
Facilitating For Healthy Trees
While trees and forests are certainly capable of taking care of themselves, when the aim is to balance food production and a healthy plant, our job is to understand how we can best be of assistance. The first step in that process is doing the research to choose those trees best suited to our particular climate and region. This might mean we don’t get to plant an orange grove in Ohio, but we have to work with the circumstances we’ve got, just like the trees. With the right tree(s) selected, our job becomes rather routine:
- Plant them when they’re sleeping. Deciduous trees experience much less shock to the system if they are planted when they are dormant. Unlike people, they respond much better if they wake up in strange place as opposed to traveling there dressed to the nines. While spring and autumn can work, it’s best to completely avoid summertime plantings.
- Leave room to grow. Dig the hole twice as wide (or more) than the root ball but only equally deep as it, such that the base of the tree is just above the surface. The wide hole gives the young roots some loose dirt to move through so that they can get themselves established, and the precise depth keeps the tree from sinking too deeply and rotting at the base.
- Maintain moisture. Young trees, even for drought-tolerant species, benefit from steady moisture in the beginning. This, of course, is best done via natural rain cycles, as well as keeping the soil protected from drying out (see: mulch). Equally so, an overabundance of water—soggy soils—can be problematic. In other words, it’s good form to pay special attention to moisture levels during the trees first couple of years.
- Mulch’em if you’ve got’em. Look down at a forest floor, and there isn’t much soil to see. It’s covered with years of organic matter: leaves, twigs, limbs, tree trunks, scat, rotting carcasses, etc. That’s how trees feel most at home: with a lot of mulch—10 cm thick, a meter wide—around their base. This protects the soil life, provides fertility, maintains moisture levels, prevents erosion, thwarts competing weeds, and so on.
- Time to prune. For the most part, deciduous trees are best pruned when in dormancy, during late winter or early spring. This produces a burst of new growth when the trees spring back to life. Fall is the worst time to prune because fungi are at their wooliest and wildest then, thus more apt to cause problems where the trees are wounded.
- Feed them in the fall. In the autumn, about a month before the first hard frost, is a great time to feed deciduous trees. Because they are dropping leaves at that time, most of the energy goes into establishing a strong root system, which ultimately insures the above-ground portion of the tree is tip-top. The stored nutrient will manifest itself in the spring. This feeding can consist of a good layer of compost, manure, or chopping-and-dropping nitrogen-fixers near them.
- Create a healthy mix. Included with the deciduous tree(s) should be a bio-diverse mix of herbs, shrubs, and other trees to create a stable ecosystem. Leave a tree all out on its own and it’s likely to be vulnerable to pests, colds, and other undesirable ailments. Surround it with support species and friends, and that’s a much healthier setting in which to grow up and acclimatise.
It’s amazing what sensible selection and minimal nurturing will do in the forest garden. With a little understanding and consideration, we can make a year in the life of a deciduous tree a superb experience for both it and us. Few things are so rewarding as seeing a tree you planted thriving, save maybe enjoying the fruits of the labour once it’s established.