Abstract: To reveal the effects of different warming modes on the fine root biomass and leaf traits of Chinese fir saplings, an experiment with factorial soil warming (ambient, +4 ℃ via cable heating) × air warming (ambient, opentop chamber (OTC)) was carried out in Sanming, Fujian Province. The results showed that the total fine root biomass of Chinese fir significantly reduced in the air warming treatment and the soil + air warming treatment compared to the control, whereas the total fine root biomass was not reduced by soil warming. Fine root biomass was significantly reduced in 0-10 cm soil layer under all the warming treatments, and was significantly reduced in 10-20 cm soil layer in the air warming treatment and the soil + air warming treatment. The biomass of fine roots in 20-40 cm soil layer did not differ among all the treatments. Leaf tissue density (LTD) and leaf mass per area (LMA) of 1-year-old leaf were significantly reduced in the soil warming treatment and the air warming treatment, while LTD and LMA of 2-year-old leaf were significantly increased in the soil warming treatment and the soil + air warming treatment. The leaf area of 2-year-old leaf was significantly reduced in the air warming treatment, the soil warming treatment, and the soil + air warming treatment. Our results suggest that Chinese fir saplings may adapt to the increased temperature by changing vertical distribution of fine root biomass in soils and leaf traits of different leaf ages. In order to reveal the effects of warming on plants more truly and accurately, the effects of different warming methods on plant traits should be considered, especially the control experiments of simultaneous warming above and below ground should be strengthened.

Key words: heating method, fine root, vertical distribution, leaf age, leaf mass per area.