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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 #232 - Trees outside forests: Functions and significance

Structurally complex forest in Queensland, Australia.Rural agroforest near Ubud, Bali.

Trees outside forests, a fundamentally multipurpose resource, are more intimately linked to the society around them than forest trees. Their productive, ecological and cultural functions are incisive, and their social, economic and environmental roles help to sustain households and household income. They are instrumental in national and international economies. They promote the conservation and sustainability of tree resources. A review of their role in peasant income acquisition strategies and potential value as economic and market indicators constitutes a challenge and innovation in the approach to forestry.

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Overstory #231 - Biodiversity: ten strategies for commodity production landscapes

Structurally complex forest in Queensland, Australia.Structurally complex forest in Queensland, Australia.


Biodiversity conservation in forestry and agricultural landscapes is important because (1) reserves alone will not protect biodiversity; (2) commodity production relies on vital services provided by biodiversity; and (3) biodiversity enhances resilience, or a system’s capacity to recover from external pressures such as droughts or management mistakes. We suggest ten guiding principles to help maintain biodiversity, ecosystem function, and resilience in production landscapes. Landscapes should include structurally characteristic patches of native vegetation, corridors and stepping stones between them, a structurally complex matrix, and buffers around sensitive areas. Management should maintain a diversity of species within and across functional groups. Highly focused management actions may be required to maintain keystone species and threatened species, and to control invasive species. These guiding principles provide a scientifically defensible starting point for the integration of conservation and production, which is urgently required from both an ecological and a long-term economic perspective.

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Overstory #230 - Uses and functions of mangroves

altMangrove forest ecosystems fulfil a number of important functions and provide a wide range of services at the local and national levels.


Mangroves are coastal forests found in sheltered estuaries and along river banks and lagoons in the tropics and subtropics. The term ‘mangrove’ describes both the ecosystem and the plant families that have developed specialized adaptations to live in this tidal environment (Tomlinson, 1986). In a dense mangrove forest, lights and shadows reflect on the water and fish and crabs hide among the submerged roots and trunks. Moving forward may sometimes be possible only by climbing on giant roots or using small boats.

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Overstory #229 - Urban tree benefits

altUrban trees and woodlands can have a profound positive effect on human, environmental, and economic health and well-being.


More than 80 per cent of us live in urban areas, and many more work or spend a substantial part of our lives in and around towns and cities. They are important for us socially and culturally, they are the places where we live and work, raise families, socialise and relax, from which we draw identity and pride. The quality of urban areas is of great importance.

Good architecture and design are clearly essential, but of equal importance is the quality of the green space. Public parks and gardens, the landscaping around buildings, street trees and highway verges, the wilder corners along river banks and canals, on railway sidings and industrial sites, and our own gardens.

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Overstory #228 - Garden Agriculture: A revolution in efficient water use

altBy redesigning the food production and supply chain around garden agriculture and urban agriculture it may be possible to achieve huge gains in resource use efficiency. Here, 87-year-old gardener Confessor Riviera shows how he grows food in his home garden.

Nearly three decades of permaculture vision, (1) teaching and activism have been closely associated, but not synonymous with “garden agriculture” (2).

Despite the global spread of permaculture and its popularity in Australia, producing food at home has remained marginal to public debates and policy discussions about sustainable agriculture, water and other resource use. In fact, permaculture and related networks have barely succeeded in stemming the loss of garden agriculture that was once an integral aspect of our household and community economies and our urban landscapes.

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Overstory #227 - Adapting forests and their management to climate change

altAgroforestry systems have potential to mitigate the effects of climate change through diversification, which can reduce risk and help stabilize livelihoods (cacao-banana-hardwood agroforest, Panama).


Forest adaptation to future environmental or social conditions resulting from climate change may significantly alter how and why forestry is practised in many parts of the globe. With the climate, and as a result the environment, undergoing perceptible changes within the life span of trees, achieving sustainable forest management will increasingly resemble aiming at a moving target.

The Intergovernmental Panel on Climate Change (IPCC, 2007) has concluded that warming of the climate system is unequivocal and most likely due to the observed increase in anthropogenic greenhouse gas concentrations in the atmosphere. In addition to the rise in average global temperatures, discernable changes have been observed in day, night and seasonal temperatures, in the frequency, duration and intensities of heat waves, droughts and floods, wind and storm patterns, frost, snow and ice cover, and in global sea levels.

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