High altitude trees. Polylepis sp. trees growing at high altitude in the Andes. These trees are amongst the highest-growing of all flowering plants. They can be found at elevations of over 5000 metres. The trees often seed near to large rock outcrops, which provide a microclimate (thermal refuge) with higher temperatures and improved soil conditions. Polylepis sp. trees are becoming rarer in the Andes, possible due to over- use by local people. Photographed in El Chaco, Ecuador.