Delivering trees to farmers: improving strategies for germplasm supply Session 2.3. Particular issues for germplasm access, quality and management at a smallholder farm level Tuesday 30 October 2007

Introduction Particular features of smallholder agroforestry systems that are constraints on tree germplasm supply and quality Will consider tree spatial distributions and germplasm management practices by smallholders Why do we need to consider these issues? Since they need to be understood in order to develop appropriate interventions at a local level

Introduction We are interested particularly in considering the implications of distributions and management practices for diversification – in order to understand how to enable farmers to diversify their businesses and environment through planting a greater variety of trees of appropriate quality Will focus on example of work done in East Africa – can consider if similar elsewhere

Tree spatial distributions Farm tree inventories tell us that… There are often many tree species in the farm landscape, but these often show very aggregated distributions. Sometimes aggregation can be at a community (‘between village’) level There are many tree species in the farm landscape but most are at very low (sometimes extremely low) densities

Tree spatial distributions In a recent survey in Kenya, more than 300 tree species were observed, but 75% of species had densities of less than one seeding tree per hectare. More than 50% of species, primarily indigenous, had a density of less than 0.25 trees per hectare The exception on low density is for a few dominant species. These are generally exotic, although, more rarely, can be indigenous. Sometimes these taxa dominate simply because germplasm of these is the most readily available

Tree spatial distributions Some of the consequences are… As farmers often must rely on on-farm sources for their germplasm (often the only sources currently available to them), low densities and aggregation lead to limited access to a diversity of species (and associated information) at an individual farmer level As densities are often very low, trees may not set seed (many species need a ‘mate’ to breed with!)

Tree spatial distributions The final result is… It is difficult for farmers to plant a wider range of species to diversify their businesses, even if they would like to

Germplasm management practices Nursery and farmer germplasm source surveys tell us that… Once trees have become established on farms, farmers often rely on these for further supply of germplasm for subsequent planting rounds (‘one off’ introductions) When undertaking germplasm collection, farmers and nursery managers tend to collect from only a small number of trees

Germplasm management practices In a recent survey in East Africa, seed to establish nursery lots was collected from an average of only 6 trees. In 22% of cases, seed to establish nursery populations was sampled from only a single tree

Germplasm management practices Some of the consequences are… The genetic base of tree species in farm landscapes, which may already be low, will become increasingly narrow. This narrowing may result in productivity losses – many tree species suffer from inbreeding depression, resulting in loss in growth, loss in fruit production, etc. A narrowing of genetic variation also results in a loss of adaptability to various pests/diseases, and an inability to respond to changing markets

Germplasm management practices The final result is… Farmers begin to experience lower productivity from the individual tree species that they cultivate. Ultimately, this may result in the loss of functionality, and hence value, of entire farm ecosystems

Possible interventions at a local level How can we address the limitations imposed by: Aggregation Low tree density Limited collection of mother trees Limited new introductions ?

Exercise: possible interventions at a local level What possible interventions can be applied to address these limitations? Table groups meet for discussion for 15 min Choose a reporter and very briefly discuss results in plenary – two key interventions only