Abstract: By using a fully automated microclimate-controlled artificial climate simulation system, this paper studied the effects of elevated temperate (ET) and doubled CO₂ concentration (EC) on the soil dissolved organic matter in a subalpine coniferous forest of western Sichuan. ET, EC, and their interaction (ETC) increased the soil dissolved organic carbon (DOC) content, with the increment being in the order of EC > ET > ETC > CK. The effects of ET, EC, and ETC on the soil DOC was greater in 0-15 cm than in 15-30 cm layer. The soil dissolved organic nitrogen (DON) content had the similar variation pattern to the soil DOC. There was no significant difference in the soil DOC/DON between different layers. ET decreased the soil DOC/DON significantly. The soil DOC and DON contents had significant positive correlations with the ultraviolet absorbency value at 254 nm (UVA_{254 nm}), indicating that UVA_{254 nm}  could be used to speculate the soil DOC and DON contents in subalpine coniferous forest of western Sichuan.

Key words: Larix potaninii var. macrocarpa, climatic response, upper distributional limit, dendrochronology, Northwestern Yunnan Plateau.