Litter Production of Different Types of Forests in Hainan and Its Impact Factors

Key words: 
• forest litter /
• annual litter production /
• litter composition /
• seasonal dynamics /
• influencing factors

Abstract: Litter trap was used to collect litters in different types of forests in Hainan Island for one year starting from November 2012 to December 2013 to analyse and compare the litter production,composition and seasonal dynamics as well as its influencing factors. The annual litter production and composition were found different in different types of forests,and the annual litter production decreased in the order of the shrubbery（5. 305 t·hm^{- 2}） ＞Monsoon elfin forest（5.636 t·hm^{- 2}） ＞ Pinus latteri forest（5.403 t·hm^{- 2}） ＞ Montane cloud forest（5.305 t·hm^{- 2}） ＞Montane rainforest（3.753 ·hm^{- 2}）. The coastal forests had higher annual litter production than the forests in the central mountainous areas,which might be the result of Typhoon. The Pinus latteri forest had the highest proportion of leaf litter（72. 26%）,the Montane cloud forest had the highest proportion of branch litter（30. 42%）,and the shrubbery had the highest proportion of fruit litter（17. 18%）. The seasonal dynamics of the litter production were different in different types of forests. A bimodal curve described the seasonal dynamic of the annual litter production in the shrubbery and monsoon elfin forest,and the peaks occurred in spring and autumn; the leaf litter production has a bimodal seasonal curve in the shrubbery,but has a unimodal seasonal curve in the monsoon elfin since it exhibited a single peak only in autumn. The branch litter production exhibited a unimodal seasonal curve in all types of forests except in the montane rainforest where the branch litter production had a seasonal bimodal seasonal curve. The fruit litter showed a unimodal seasonal curve in all the types of forests except in the shrubbery where the fruit litter production had a bimodal seasonal curve.The annual litter production and its composition were not significantly correlated with the stand characteristics in the shrubbery,and the leaf litter production and the annual litter production exhibited a significant correlation（P ＜0.05） with the stand density in the monsoon elfin forest. The annual litter production and its composition failed to show significant relationship with the terrain factor in the same types of forests in Tongguling mountain.