This paper gives a general view of researches done by the Centre Technique Forestier Tropical on growth stresses. We present their consequences for felling and sawing, specially for certain commercial guyana timbers. The different technics to measure the growth stresses level are described with a particular attention for the methods available for trees selection in forest. The paper gives a summary of the principal results and proposes some technics to improve felling and sawing with special recommendations for the user.