Introduction

Have you ever picked berries from the edge of a forest in a city park? Made a holiday wreath from wild grapevine growing in your backyard? Collected the nuts of a Chinese chestnut street tree? Or harvested pokeweed growing in an abandoned lot? Many people do collect such products -- and others -- in cities. These urban nontimber forest products (NTFPs) represent important economic, nutritional, biological, educational, and cultural resources for a diversity of urban residents (Community Resources 2000).

Within the past ten years, people have increasingly recognized nontimber forest products for the important cultural, subsistence, and market values that they add to rural forests and individual households worldwide. Nearly all ethnic groups around the globe rely on NTFPs for household income, food, medicine, construction supplies, and materials for decorative and ceremonial purposes. These resources are especially important during times of economic hardship or during lulls in agricultural production (Saxena 1986).

Introduction

Farmers have integrated trees in their farming systems for centuries. They did not wait for scientists to develop the concept of agroforestry, just like man did not wait for agronomists to invent and develop agriculture. Agroforestry is widely promoted as a solution for developing more sustainable land uses. But most policy makers, scientists and extension agents dealing with agroforestry programs rarely consider that most agroforestry systems have evolved from local farmers' practices. What farmers are actually doing indeed differs from one country to the other in the region. However, agroforestry is still mainly understood in terms of "development projects," and therefore is usually promoted from an outside point of view, with outside tree crops or mixed-cropping techniques. With few exceptions, projects do not explore either the local agroforestry knowledge base nor the local farmer-developed agroforestry practices.

What is soil conservation?

Soil conservation basically means a way of keeping everything in place, literally as well as in a more abstract sense of maintaining the functions of the soil in sustaining plant growth. Soil conservation practices involve managing soil erosion and its counterpart process of sedimentation, reducing its negative impacts and exploiting the new opportunities it creates. Young (1989) defined soil conservation as a combination of controlling erosion and maintaining soil fertility. In the past the focus has often been on trying to keep the soil at its place by plot-level activities only. Currently, the attention has switched to landscape level approaches where sedimentation is studied along with erosion, and the role of channels (footpaths, roads and streams) is included as well as the 'filters' that restrict the overland flow of water and/or suspended sediment.

Introduction

The older approach to land management, based on the transfer of Western technologies, has been replaced by a new set of ideas. For management of the croplands, new approaches include the land husbandry basis for soil conservation, low-input sustainable agriculture, and small-scale irrigation. On open rangelands, reconciling the extreme complexity of land management needs with communal tenure raises problems which are almost insuperable. Multiple-purpose forest management has replaced the earlier focus on wood production. Agroforestry has helped to diversify farm production, and offered new means of soil management.

Introduction

To one degree or another, most plants in their natural habitats function under the influence of a special group of soil fungi known as arbuscular mycorrhizal fungi ("AM fungi" or AMF). The existence of these fungi has been recognized for more than a century, although they did not receive the attention they deserve until approximately 40 years ago. Worldwide, interest in AM fungi has now reached a point wherein any discussion of agricultural biotechnology that does not include their role in plant productivity can hardly be considered complete.

Many individuals and organizations concerned with managing native plant species, restoring natural ecosystems, and producing agronomic, horticultural, and forest plants with minimal chemical inputs are interested in applying AMF technology. A major challenge to the large-scale utilization of AMF is the unavailability of large quantity of high quality inoculum to introduce the fungi into plant growing media. The problem of producing inoculum is largely due to that AM fungi are "obligate symbionts," which means they require the presence of actively growing plants during their reproduction. Therefore AMF cannot be cultured on laboratory media in the same manner as other beneficial soil microorganisms such as Rhizobium bacteria. Fortunately, specialized techniques for AMF inoculum production have been in development at the University of Hawaii and elsewhere.

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