Environmental studies combine the tree species identification of charcoal collected from iron smelting furnaces and open hearths, palynological analyses of high altitude and valley peat bogs as well as in archaeological structures as well as phyto-sociological and geomorphologic data. The settlement period of the Urewe civilisation should be seen in the context of a cooling and drying out period in about 1000 BC. Those members of the Urewe civilisation who settled in Rwanda and Burundi did so exclusively in the hills region (central plain) in a 1700 and 1300 meters high zone on clay soils on primary substrate which are some of Africa's richest. The undulating countryside, covered with woodland savanna (tree cover vegetation, sparser on the slopes and denser in valleys and on crests) together provided good living conditions (moderate temperatures and average rainfall, protected from carriers of human and animal disease) encouraged a variety of activities. The Urewe would have lived a relatively sedentary life as farmers, devoting themselves to agriculture (including cereal growing) and small-scale cattle rearing. They do not appear to have supplemented their diet by hunting and fishing as will be the case in these areas in the late Iron Age, and which occurred in the early Iron Age in those more east-lying Urewe civilisations around Lake Victoria, influenced perhaps by contacts with nomadic communities along the east African Rift Valley. Combined human activities, land clearance, ironworking, cereal growing, etc., led to the deforestation of fringes of the great forest which once covered the north–south backbone as well as the forest corridors along the water sources which caused soil erosion on the slopes. This phenomenon led to the extensive erosion of Kabuye hill near Butare as a result of their occupation of the site for about 500 years. The hilly region of Rwanda and Burundi was probably a well frequented route from the northern to the southern hemisphere in Africa and would therefore have regularly experienced the relative overcrowding of people fleeing the drought-ridden Sahel regions which impeded
soil regeneration. On the contrary, the impact of human activity, combined with consecutive periods of hot, dry climatic conditions have only served to aggravate
soil degradation up to modern times. Since the 7th century, the appearance of simpler, roulette-decorated, ceramic pottery as well as new types of iron furnace, heralded a major change towards the late Iron Age. However, the Urewe civilisation did manage to survive in isolated pockets at least up to the 14th century. ==Archaeologists in the field area==