This paper discusses various aspects of the design and costs of riparian protection zones in the humid steeplands of the Luquillo Mountains of Puerto Rico. This riparian community is dominated by successional species and can be protected without large losses in commercial timber. However, the cost of buffers increases geometrically as smaller order channels are buffered. Generally the costs associated with protecting intermittent streams is prohibitive in this highly dissected terrain. Depending on the design criteria used, protection zones along perennial streams can include between 5 and 20% of the commercial basal area while protecting 9 to 25% of the watersheds area.