A free email agroforestry journal for practitioners, extension agents, researchers, professionals, students, and enthusiasts. One edition is sent each month focusing on a concept related to designing, developing, and learning more about trees and agroforestry systems. Focuses on trees and their roles in agriculture, natural ecosystems, human culture and economy.

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Overstory #179 - Trees outside forests

Summary

Rural people around the world are of one mind when it comes to the durability, availability and use of the goods and services provided by tree resources, whether inside or outside the forest. These men and women make no distinction between field trees and forest resources, perceiving the clear and close link between the two, and their interaction. Policy-makers and planners, however, tend to view these resources as different entities. It seems clear that Trees outside forests have not yet succeeded in arousing real interest at the top. So there is a need to describe and comprehend the dynamics of trees and shrubs on rural and urban land, and their interaction with forest dynamics. This should lead to a better understanding of off-forest tree management and towards integrated and sustainable management of natural resources and of forest, farm, pastoral and urban land.

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Overstory #178 - Sustaining native bee habitat for crop pollination

Introduction

Over one hundred crop species in North America require a visit from an insect pollinator to be most productive. In the past, native bees and feral honey bees could meet the pollination needs of small orchards, tomato and pumpkin fields, and berry patches, because these farms were typically adjacent to areas of habitat that harbored important pollinators. Today, many farms are large and, at the same time, have less nearby habitat to support native pollinators. To ensure adequate pollination services, producers now rely on European honey bees. Research, however, shows that native bees can be important pollinators in agricultural fields as long as enough habitat is available.

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Overstory #177 - Ten percent multipurpose tree cover for every farm: A low risk, high opportunity first step

Abstract

Agricultural research suggests that farmers can confidently plant trees for shelter and land protection across at least five per cent of their farm without risking agricultural productivity or capital value. Most farmers could increase this to 7 or 8 percent by protecting native remnants, targeting land of low agricultural value and extending ornamental plantings. Farmer and community acceptance of the potential for these same trees to produce commercial products (agroforestry) could well justify the extra required to achieve ten percent tree cover across the farming landscape. Rather than threatening agriculture, ten percent multipurpose farm tree cover could reduce risk and provide greater opportunities for farm families and their local communities.

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Overstory #176 - Trees for nature conservation

Introduction

If you have decided to use trees to maintain nature conservation values in your landscape, it is important to be clear about what you are trying to achieve. The actions that you take will vary considerably, depending on your objective. There are two broad approaches that you can take:

  • the 'easy' option, which aims to 'make the landscape better' for nature conservation. This approach, sometimes called 'general enhancement', provides a wide range of general ecological principles that can be applied to your agroforestry enterprise; or
  • a 'species retention' strategy. This has the more ambitious goal of keeping all of the species that currently occur in the landscape. General guidelines will not be sufficient for this task. Instead you will have to manage your landscape so that it meets the needs of the species that are there. This means knowing something about those species and any additional management which may be required to meet this type of objective.

The design principles for these two approaches differ considerably. This chapter focuses on design principles for general enhancement, as these require less knowledge about the plants and animals and are easier to apply within the context of an agroforestry enterprise.

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Overstory #175 - Deep pipe irrigation

Deep pipe irrigation

One of the great challenges for agriculture, agroforestry, forestry and restoration is to establish plants on seasonally or continually dry sites (Kolarkar and Muthana, 1984; Bainbridge, 1991). This becomes even more difficult at remote sites where water must be carried in by hand, animal or truck. Traditional irrigation methods such as furrow or basin watering, sprinklers and even drip irrigation demand too much water and require filtered and pressurized water, as well as regular maintenance. In areas where the need for plant establishment is greatest, these requirements are usually too costly, technical or time consuming to manage. What can we do?

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Overstory #174 - The role of trees in aquaculture systems

Summary

There are numerous instances of the intentional co-management of trees and aquatic organisms, though there are only limited specific studies on these interactions. Also, in addition to the direct interactions of forests, plantations and orchards trees on aquaculture, the use of tree products is widespread, as wood, fibres, food, poisons and other chemicals. On both micro and macro scales, there are many ecological interactions between trees and aquaculture. Trees play important environmental roles, ameliorating soil chemical and physical structure, shade and little fall, reducing soil erosion, increasing water infiltration, flood limitation, etc., that impact directly, or indirectly, on water quality and quantity. Thus, forest, plantation and orchard management practices and systems will clearly affect local and regional water bodies, and subsequently aquaculture activities. This paper aims to draw attention to the valuable role that trees play in aquaculture systems, either as consciously managed combined 'silvoaquaculture' systems, or incidentally via unmanaged environmental interactions.

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