Chin J Plant Ecol ›› 2010, Vol. 34 ›› Issue (9): 1007-1015.DOI: 10.3773/j.issn.1005-264x.2010.09.001

• Research Articles •     Next Articles

Litter stocks and chemical quality of natural birch forests along temperature and precipitation gradients in eastern Inner Mongolia, China

CHEN Sha-Sha1, LIU Hong-Yan1,2, GUO Da-Li1,2,*()   

  1. 1Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
    2Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
  • Received:2010-04-22 Accepted:2010-06-09 Online:2010-04-22 Published:2010-10-08
  • Contact: GUO Da-Li

Abstract:

Aims Forest litter is both a large source of CO2 released from terrestrial ecosystems to the atmosphere and a critical sink of carbon and nutrients for plant growth. Studying dynamics of forest litter and its response to temperature and precipitation changes can improve our understanding of forest carbon and nutrient cycles and their interactions with projected climate change. Our objective was to examine the stocks and chemical quality of forest litter in natural birch (Betula platyphylla) forests that vary in both annual mean temperature (AMT) and annual mean precipitation (AMP).

Methods During July and August 2008, we measured the standing stocks and concentrations of carbon, nitrogen and phosphorus and organic fractions (extractives, acid soluble fraction (AS) and acid insoluble fraction (AIF)) of three litter layers (L1: slightly decomposed layer, L2: half-decomposed layer and L3: humus layer) in the forest floor of 12 birch forests in Inner Mongolia, China.

Important findings Along the decomposition gradient (i.e., from L1 to L3), nitrogen and phosphorus concentrations increased, AS concentration decreased, AIF concentration increased but extractives did not show significant change. Temperature and precipitation did not have significant effects on carbon fractions but at sites where AMT was higher, carbon stocks in L3 layer were higher, probably because of greater accumulation at higher-temperature sites as a result of higher litter production but similar decomposition rate compared to lower-temperature sites. These findings indicate that the litter layer (particularly the L3 layer) is an important carbon and nutrient pool at the ecosystem scale and future increases in temperature without concurrent increases in precipitation may enhance litter accumulation in these natural birch forests.

Key words: Betula platyphylla, decomposition, litter, precipitation, temperature