During the Viêt Nam war, the American army sprayed herbicides and dropped bombs. The purpose was to defeat the enemy by destroying its environment, especially the forests. That’s why some authors claim that this war is one of the main causes of forest loss but without demonstrating. They consider that the areas affected by the military practices were forested but did it correspond to the reality? The pre-war landscapes have to be reconstructed, basing on aerial photographs. These iconographic data are raw, therefore a priori unbiased. The studied landscapes were those of the Thua Thiên Huê province, particularly affected by the war; their reconstruction is only partial, because the photographs processing is long. Also necessary, the knowledge of the post-war landscapes is based on another iconographic data, a satellite image; this one covers the province and requires a shorter processing. By comparing these pre- and post-war landscapes, we can objectively identify the wartime dynamics. Some forests were destroyed but other sylvo-ecosystem progressed. Besides the military practices, the civilian practices explain these dynamics.