This chapter examines the various elements that lead to environmental disturbances and show that endogenous factors, such as farmer income-earning strategies and the size of the colonist family, are especially significant. It presents a description of the deforestation problem, a case study of the upper Huallaga valley based on results of a survey administered in 1981 by Carlos Aramburu, and a synthesis and discussion of ecological degradation, including policy recommendations. The production of coca and annual crops has led to ecological degradation in the upper Huallaga basin. For annual crops, the relation between cultivated and fallow periods in upper Huallaga basin is an additional symptom of degradation. Land management in the case of coca cultivation in zones of excessive slope is as much a result of highland custom—where such terrain is cultivated without major problems—as it is of the national economic context, which requires the peasant to cultivate lands that are not adequate for such use.