Editor’s note: This is a post by our intern Andrew.
Trees play a lead role on our farm. More than just a source of fruit and a pleasing landscaping feature, trees are valued within permaculture design for their complex array of functions within any ecosystem. Trees and forests work wonders in preventing soil erosion, regulating the extremes of humidity and temperature, managing the soil moisture, and acting as a windbreak.
It is unsurprising that permaculturists are enamored with trees. The ethos of permaculture is to “design and maintain agriculturally productive systems which have the diversity, stability, and resilience of natural ecosystems.” And the prehistoric state of most ecosystems on earth’s surface was characterized by forest. Here in New Zealand, before the arrival of humans, 85% of the land mass was tree cover whereas that figure is barely above 30% today. A similar story has played out globally as the march of human presence and capabilities has been synchronous with the felling of forests.
We often imagine history with humans as the protagonists, domesticating other species in our quest for global domination. But an equally valid perspective is to instead think of grasses, in the form of maize, wheat and other staples, domesticating humans to do the work of clearing trees. We open up space for our masters, grass, to grow and flourish.
As any permaculturist knows, the clearing of trees is accompanied by a host of adverse consequences to the surrounding ecosystem. In the Lebo’s case, they inherited a damaged property suffering after years of clearcutting and overgrazing, a hillside in danger of slips, and a flooding creek tearing away at its banks. It is true that left to its own devices, cleared land will slowly grow back into forest over the course of many years. Grasses will be succeeded by shrubs, then small trees, and finally bigger trees.
But to stop the bleeding, the Lebo’s top priority on this land has been to intervene to speed along the recovery process by planting over a thousand trees. Many of these adorn the bare hillsides and blanket the creek beds to slow erosion and prevent the creek from widening and swallowing more of the land. Others are fruit-bearing, grown as part of a future food forest, both feeding us and the community, providing forage for birds and pigs, and acting as a wind and soundbreak from the main road. With so many young trees, caring for them can be a full-time job.
Like any living creature, trees need water. Whereas full-grown trees possess wide and deep root systems rendering them more resilient during drought times, young trees still need to be coddled. Much of this dry summer has seen us directly watering the young poplar, olive, and manuka trees dotting the hillside. To increase the effectiveness of the watering, the trees were planted inside small depressions in the shape of small bowls. Since they are on a hillside, this is an important step to ensure that water soaks into the earth directly on the plant and thereby encourages deep root growth.
In addition, we like to give our baby trees a leg up in the competition for water and nutrients by occasionally patrolling the trees to pull the grasses and weeds in the immediate vicinity of their tiny trunks to maintain a small circumference of cleared space. Many of the trees are so small that they would otherwise be completely overrun and suffocated by the tall grasses and vines that can spring up during wet spells. We lay the pulled grasses back down around the base to act as a mulch. This aids in slowing water evaporation from the soil around the tree and inhibiting the resurgence of grasses and weeds by shading them out.
As the trees age, sometimes plants are purposefully planted around the base of the tree. Down the road in Whanganui, the Heritage Food Crops Research Trust has bushes of comfrey growing around the base of some of the fruit trees. Comfrey acts as a living mulch to prevent the overgrowth of grass, but it also is particularly useful in its role as a dynamic accumulator, mining nutrients from far within the soil with its deep roots. These nutrients can be added back to the soil by frequently trimming comfrey leaves and laying them down as mulch or by making a comfrey tea out of them.
Much of caring for trees is knowing the appropriate microclimate in which to plant them. For example, we have a few potted citrus trees we are hoping to transplant into the ground soon. However, citrus trees abhor having wet feet, which, given the realities of the clay soils and wet winters, is hard to avoid. With this in mind, we have taken a plot from the garden and built a hugelkultur in order to create a small rise in the land to create a drier corner.
Avocado trees, while enjoying plentiful water, are also susceptible to root rot if kept too moist. They will therefore be planted at the bottom of our hill but on a small plateau. This area has the additional benefit of being one of the only places on the property with free-draining sandy soil.
Sometimes, a succession of trees should be planted to mimic ideal growing conditions. Take the avocado trees again as an example. When avocado trees are young, they must grow under shade. In our case, we will plant tagasaste as a nurse tree a full season before planting the avocado. Tagasaste is an ideal nurse tree, being easy to propagate from seed and providing nitrogen fixing and shade. In addition, tagasaste is a short-lived tree, so by the time the avocado tree has matured enough to hold its own, the tagasaste can be harvested for firewood.
On an organic farm, keeping pests and diseases down naturally is important. We have invested in a wide diversity of tree species and varieties to safeguard against any one pest or disease from thriving and wreaking havoc throughout the whole property. In addition, we purchase only the most disease-resistant varieties. Pruning has a role in disease prevention as well. Pruning off dead, diseased, or damaged branches maintains a healthy tree and opens it up to better air circulation.
One last factor that should always be considered is protecting trees from potential damage wrought by prevailing winds as well as other animals on the farm. As Nelson always says, “You have to plan 110% for animals.” We take extreme precautions with bulletproof fencing for the goats on the farm. If they get into the adjacent orchard, they could eat the young trees to death in the course of a short afternoon, decimating years worth of investment.
All in all, trees are an irreplaceable keystone to any permaculture design. Caring for them can be a handful, but is always well worth the work.