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 #226 - Are Trees Long Lived?

altDoes the next generation of ancient and veteran landscape trees have its beginnings in our cities and communities?

The ancient and veteran trees we enjoy today developed in wild unmanaged forests of the past, in protected forest preserves and on agricultural lands. As communities spread, some of these trees have become part of our community forest. Society also has set aside some forests to remain wild and to maintain ancient trees in their natural habitat. We hope that the current veteran and ancient trees will remain with us for many more years. Does the next generation of ancient and veteran landscape trees have roots in our cities and communities today?

The myth of long-lived trees

Dr. Alex Shigo’s first entry in his book 100 Tree Myths is the myth that “trees are so big and tough nothing can injure them.” The passage continues with the observation that many trees die because of abuse from human activity. Undoubtedly, this is true, but what is the context for tree survival in the forest? For students and teachers of tree biology, the answer to that simple question is not so simple! Even such an obvious statement that “trees are long-lived” is not quite right. That statement is based on a tautology, related to the identity principle in arithmetic, that 1 = 1. Tautologies are true, but not very useful. Sure, long-lived trees are long lived. In my dendrochronology research, I’ve had the pleasure to work with trees that are more than several centuries old. But are trees usually long-lived in natural or community forests?

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Overstory #225 - Tree domestication for multi-functional farming systems

altMulti-functional agriculture has the potential to simultaneously achieve economic, social and environmentally sustainability by restoring biological resources and natural capital, livelihoods, and agroecological processes.


The increasing loss of forest resources in tropical countries leaves farmers without the food and other products that used to be gathered locally. This coupled with land degradation creates a poverty trap from which it is difficult for smallholder farmers to escape. To address these problems, the domestication of new perennial crops from traditionally important indigenous trees is seen as a way to diversify farming systems making them more sustainable through the provision of a range of products and environmental services. This enriches existing mixed tree/crop farming systems and creates new ones that are more productive and enhance the livelihoods of poor households. A participatory approach to tree domestication is used to ensure that farmers’ needs are met. This approach is in accord with the findings of the International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD), which has recently identified the need for agriculture to be more multi-functional and to simultaneously achieve economic, social and environmentally sustainability by restoring: biological resources and natural capital (soil fertility, water, forests, etc), livelihoods (nutrition, health, culture, equity, income), and agroecological processes (nutrient and water cycles, pest and disease control, etc.).

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Overstory #224 - Global Extent and Geographical Patterns of Agroforestry

altAmong other findings, this study reveals that on more than 1 billion hectares of the world’s farmlands tree cover exceeds 10%.


Agroforestry, the inclusion of trees within farming systems, has been a traditional landuse developed by subsistence farmers throughout most of the world. In the last 40 years it has also become a subject for systematic study and improvement, and a livelihood option promoted by landuse managers and international development efforts. It has come to the attention of global analysts and policy makers, for example UNFCCC (2008) and MEA (Hassan et al 2005), and has been recognized in regional and national development plans (NEPAD 2003) and is an obvious component of many farming systems.

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Overstory #223 - Conducting landscape assessments for agroforestry

copyright Craig ElevitchLandscape assessment illuminates relationships between landscape structure, environmental problems, and agroforestry opportunities.


Landscape assessments describe existing resource conditions and trends within a larger planning area and identify opportunities to produce environmental benefits with strategically placed management activities, including agroforestry practices. In this Agroforestry Note, we:

  • Explain why assessing the landscape is important for agroforestry
  • Describe a basic landscape assessment process
  • Discuss ways to use landscape assessments for agroforestry

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Overstory #222 - Forests and human health in the tropics: some important connections

copyright Craig ElevitchTropical forests provide essential foods, medicines, health care and mental health benefits to people all over the world.


Why should foresters concern themselves with issues of human health? There are at least two important answers to this question. First, and perhaps most fundamental, forestry activities affect human health and human health affects forests. Second, the United Nations Millennium Development Goals (MDGs) (see below), which the world’s countries have committed to meet by 2015, reflect increasing global concern about human health. Four of the MDGs (1, 4, 5 and 6) address health directly. It can also be argued that improvements in human health (as part of human well-being) are a prerequisite for accomplishing the seventh goal, which is the most pertinent for foresters.

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Overstory #221 - Economics and Farm Forestry

altEconomic analysis tempered by considerations of uncertainties is essential to farm forestry planning.


Understanding the economic tools used to assess the viability of a long-term project such as farm forestry is very important if a farmer is to make an informed investment decision.

Understanding these tools also allows:

  • A farm forestry project to be evaluated against other investments, such as investing in the stock market or building a new dam;
  • The cash flow of a project to be assessed;
  • The financial aspects of the project to be analysed; and
  • The economic risks to be highlighted right from the start of the project.

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