摘要：Climate change could cause alpine treelines to shift in altitude or to change their spatial pattern, but little is known about the drivers of treeline dynamics and patterning. The position and patterns of tropical alpine treelines are generally attributed to land use, especially burning. Species interactions, in particular facilitation through shading, may also be important for treeline patterning and dynamics. We studied how fire in alpine vegetation and shade dependence of trees may affect the position and spatial pattern of tropical alpine treelines and their response to climatic warming, using a spatial minimal model of tree growth at treeline. Neighboring trees provided shade and protection from fire. The positive feedback that resulted from these neighbor interactions strongly affected the emergent treelines and always reduced the distance and speed of treeline advance after a temperature increase. Our model demonstrated that next to fire, shade dependence of trees can also lead to abrupt treelines and relatively low treeline positions. This implies that these patterns do not necessarily indicate human disturbance. Strong abruptness of a treeline may indicate that it will respond slowly to climatic changes.
