Integrated ecosystem and landscape approaches to conservation are moving from concept to practice in many parts of the developing world. Agroforestry -the deliberate management of trees on farms and in agricultural landscapes -is emerging as one of the most promising approaches to enhance and stabilize rural livelihoods, while reducing pressure on protected areas, enhancing habitat for some wild species, and increasing connectivity of landscape components. For the potential of agroforestry to be effectively harnessed, however, the policy and institutional environment needs to provide farmers with clear incentives to plant and protect trees that contribute to both ecosystem function and rural livelihoods. This paper analyzes the policy terrain affecting agroforestry around protected areas in five very different contexts across Sub-Saharan Africa, finding both expected and unexpected similarities. Across the sites in Uganda, Cameroon and Mali, the study revealed a rough policy terrain for agroforestry -systemic market constraints, contradictions between development approaches and conservation objectives, and inconsistencies in institutional and regulatory frameworks. Making the conservation landscape approach more effective will require that both agriculturalists and conservation planners have much greater appreciation for the conservation and livelihood potential of agroforestry.

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If the student of organic chemistry has before him tetrahedra models he seldom fails to visualize space isomerism, the asymmetric carbon atom, and the effect on polarized light of compounds having this configuration. The use of these models makes unnecessary much blackboard work involving drawings representing tetrahedra and so relieves the instructor of a task at which he may not be very adept. The tetrahedra pictured in this article are easy to construct and the time consumed is well repaid by the quickness with which the student grasps the idea and the short time necessary for the presentation of the subject when tetrahedra models are shown. The results are well worth the trouble.An equilateral triangle d ef, say 8" on a side, is first laid out on medium weight stock. If each side is bisected at a, b, and c as shown in