The greatest problem in making these strategies working, I think, is related to the capacity of the people living in a certain place of planning long term.Some times is difficult to convince a farmers to plant even a fruit tree that after some months will begin to produce.Can you imagine how much they care about planting trees or getting involved in agroforestry?
Links and resources:
International Conference on Forests for Food Security and Nutrition
FAO Forestry Department
Learning event on Agroforestry