Forests are often frontiers, and like all frontiers, they are sites of dynamic social, ecological, political and economic changes. Such dynamism involves constantly changing advantages and disadvantages to different groups of people, which not surprisingly can lead to armed conflict, and all too frequently to war. Many governments have contributed to conflict, however inadvertently, by nationalizing their forests, so that traditional forest inhabitants have been disenfranchised while national governments sell the rights to trees in order to earn foreign exchange. Biodiversity-rich tropical forests in Papua New Guinea, Indonesia, Indochina, Myanmar, Sri Lanka, Central and West Africa, the Amazon, Colombia, Central America and New Caledonia have all been the sites of armed conflict in recent years, sometimes involving international forces. Forests have sometimes been part of the cause of conflict (as in Myanmar and Sierra Leone) but more often victims of it. Violent conflicts in temperate areas also typically involve forests as shelters for both civilians and combatants, as in the Balkans. While these conflicts have frequently, even invariably, caused negative impacts on biodiversity, peace can be even worse, as it enables forest exploitation to operate with impunity. Because many of the remaining forests are along international borders, international cooperation is required for their conservation. As one response, the concept of international “Peace Parks” is being promoted in many parts of the world as a way of linking biodiversity conservation with national security. The Convention on Biological Diversity, which entered into force at the end of 1993 and now has 187 State Parties, offers a useful framework for such cooperation.