In the third treeline session for the conference, the emphasis shifted to competition and ecosystem processes operating within the treeline ecotone. The session continued to be well attended even for one late in the day. Alison Hester started out the session by reporting on a multi-authored meta-analysis of the importance of herbivory at treeline. The most important finding was that there is a dearth of herbivory research at treeline, but that many people are speculating that it is important. James Speed presented some results of a herbovor exclosure/enclosure study in Norway and showed that herbivores were important agents on the landscape and talked about how their activity impacts carbon stocks. Sandra Angers-Blondin discussed the influence of plant size on the climate sensitivity of tundra shrubs, and Melissa Dawes discussed Nitrogen dynamics at a treeline warming experiment. Andrew Trant discussed how repeat photography from the Mountain Legacy program could be used to qualitatively evaluate the change in treeline position in the Canadian West. Finally, John Shaw presented information about the Forest Inventory Analysis database for the western United States.