Editor's Note

Mushrooms are the fruiting bodies of certain types of fungi, many of which can play highly beneficial roles in forest ecosystems. Many of these fungi have unique abilities to break down wood, leaves, and other organic matter and recycle nutrients back into the system. Most plants depend on symbiotic relationships with certain types of fungi such as mycorrhizae (see Overstory #8). Other types of fungi support plants indirectly by releasing enzymes into the environment, making nutrients available, and performing many other functions. Fungi can be a great asset to a farm system, both for their ecological services and for their valuable edible and medicinal products.

Special guest author Paul Stamets describes here a number of important edible and medicinal mushrooms, and how they can be integrated into permaculture and agroforestry systems. Paul is the author of The Mushroom Cultivator and Growing Gourmet and Medicinal Mushrooms. He operates Fungi Perfecti, a company serving mushroom cultivators throughout the world.

Permaculture with a Mycological Twist

When edible and medicinal mushrooms are involved as key organisms in agriculture and forestry, the productivity of these agricultural systems can soar to extraordinary levels. Not only are mushrooms a protein-rich food source for humans but the byproducts of mushroom cultivation unlock nutrients for other members of the ecological community. The rapid return of nutrients to the ecosystem by mushrooms boosts the life cycles of plants, animals, insects (bees), and soil microflora.

Multipurpose Windbreak Design: Balancing Function and Yields

Windbreaks are rows of vegetation, usually trees, strategically placed to protect an area from winds. Although planting windbreaks is an investment that takes some land out of production, well-designed windbreaks have often been shown to protect the health and productivity of crops enough to make the overall return positive. Farmers in the tropics have looked at finding ways to increase the benefits further by creating multipurpose windbreaks. A multipurpose windbreak is designed to provide multiple functions and/or products, in addition to wind protection. Multiple produces from a windbreak can include yields such as fruit, timber, animal fodder, mulch, wildlife habitat, and other economic or farm products.

Adding multiple functions or products to a windbreak plan can make the installation and management more satisfying and economically viable for the farmer. The desire for additional yields must always be balanced by the need to maintain the integrity of the wind protection.

Editor's Note

Previous editions of The Overstory have covered the value of increased diversity (Overstory editions #14 and #21), using trees that do well in your area (Overstory #9) and tree seed selection (Overstory #19). In this edition, these topics merge in the subject of "tree domestication," bringing wild tree species into cultivation in agroforestry systems. Special guest author Dr. Roger R. B. Leakey , Head of Tropical Ecology, Institute of Terrestrial Ecology, Midlothian, UK, shares an excerpt adapted for The Overstory from his original work appearing in Agroforestry for Biodiversity. For more details about this publication, please see the reference below.

Domestication of Trees for Timber and Nontimber Forest Products

Throughout the tropics there are numerous perennial woody species that have provided indigenous peoples with many of their daily needs for millennia. Many of these people have now left the land for urban life, but they still demand traditional food, medicines, and other natural products. These traditionally important woody plants are virtually undomesticated. These neglected "Cinderella" species have great genetic diversity and also play a key role in biological, chemical, and hydrological cycles, protecting soils and providing ecological niches. The food-producing species are also important for food security, especially in the dry season, as well as a source of vitamins and minerals critical for the health and nutrition of children and pregnant women.

Many of the most useful bamboo species can occupy much the same ecological niche as trees, and are well suited for agroforestry. Bamboo has many advantages over trees such as a relatively short time from planting to harvest, the ability to sustainably provide building materials and edible products for many years or even decades, and versatility of use which outmatches most tree species. For its ecological adaptability, and wide range of uses, bamboo can be an essential component of many agroforestry systems.

Bamboo belongs to the grass family (Gramineae), subfamily Bambusoideae. There are over 1500 bamboo species recorded, ranging in height from a few inches (cm) to over 100 ft (30 m), with stem (culm) diameters of 1/8 inch (3 mm) to over 10 inches (25 cm). Bamboos are found in a very wide range of habitats from tropical to temperate, arid to humid and coastal to montane.

Editor's Note

In Overstory #20, Roland Bunch shared his five principles for maintaining farm fertility. In this issue, Roland Bunch summarizes the most important aspects of what is known about green manure/cover crops in the tropics for maintaining or improving farm productivity.

Tropical Green Manures/Cover Crops

What are green manures/cover crops? The terms "green manure" and "cover crops" originated from practices of using primarily leguminous plants and plowing them under to fertilize soils. However, as the practice has spread to the tropics, different conditions have generated different uses, and the practice has changed. The terms remain although many tropical farmers do not use the vegetation green, nor do they normally plow it under as one would a manure. The terms now refer to a series of plants, mostly leguminous, which are used by farmers for a whole range of purposes, one of which is the fertilization and improvement of the soil by applying the vegetation to the soil surface. In the following, the term green manure is used to cover both green manure and cover crops.

Microlife: The unseen community we depend on

Microorganisms permeate the soil, water, and air of our planet. They existed for billions of years before any plants or animals existed, and continue to be the most abundant form of life on Earth. Microorganisms created the atmosphere, turned bare rock and lava into soil, made possible the eventual evolution of larger life-forms, and continue to dominate the lives and functions of all living plants and animals. They are of key importance to every ecological process happening on the planet.

The general public normally only hears about microorganisms in terms of viruses or harmful bacteria, to be battled with soap, disinfectants, and other weapons in our modern arsenal. However, in general the functions of most microorganisms are benign or very much to our benefit, and to destroy them would be to destroy ourselves. The human body, for example, is teeming with microlife--about 10% of the average human's body weight is made up of microorganisms! Each square centimeter human skin hosts an average of 100,000 bacteria, maintaining the health of the skin, and countless millions occupy our intestines. Our vital abilities to breathe and digest food are all intricately linked to the microorganisms that reside within us and make our life possible. As the biologist Lynn Margulis said, "Beneath our superficial differences we are all of us walking communities of bacteria." The web of life depends on this vast network of microorganisms.