A substantial body of research has established that in-stream wood can be important to the geomorphological and ecological function of temperate streams, but very few studies have documented the role of wood in tropical streams and rivers. We measured in-stream wood structure and function in seven separate headwater stream networks radially draining Mt. Orosi, a dormant stratospheric volcano within the Guanacaste Mountains of Costa Rica. Measured wood loads were lower than typical of temperate systems. Wood loading increased with drainage area, whereas the opposite trend is typically observed in other similar studies. Most of the wood was fully contained within stream channels and in advanced stages of decay. The most common function was to form a step in the bed profile. Few jams were observed. Wood loading was highly variable over longitudinal space and across stream networks, suggesting that steady state delivery may not be the primary control on wood loading in these systems. Rather, episodic inputs associated with mass movements and/or high intensity storm events may drive wood recruitment into tropical montane headwater streams.