PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Soil respiration and its components of five forests in Northeast China.

WANG, Wen-Jie¹, ZU, Yuan-Gang¹, ZHANG, Xian-Quan¹, HIRANO, Takashi ², KOIKE, Takayoshi ³, ¹ Key Laboratory of Forest Plant Ecology of the Ministry of Education, Northeast Forestry Univ., Harbin 150040, Heilongjiang Province, P.R, China² Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Hokkaido, Japan³ Hokkaido University Forests, FSC, Sapporo 060-0809, Hokkaido, Japan

ABSTRACT- Five forest types (Abb., common name, Latin name:i.e. L: Larch, Larix gmelinii plantation; BL: Birch and Larch, mixed forest of Betula platyphylla and L. gmelinii; A: Ash, Franxinus mandshurica plantation; K: Korean pine, Pinus koraiensis plantation; S: Scots pine, P. sylvestris var. mongolica plantation) in the same study site (45^o20^'N,127^o34^'E) were selected to find the effect of tree species on soil respiration (2001-2004). Methods of trenched box and litter exclusion (initiated in 2002) were used to separate total soil respiration (R_t) into the components of litters (R_l), roots (R_r) and soil microbes (R_m). Classification of these five forests into two categories of deciduous (L; BL and A) and evergreen (K and S) forests, we found root contribution more to R_t in deciduous species comparing to that of evergreens. Moreover, significant higher Q₁₀ values for R_t and R_l+R_m were found in deciduous forests, but not R_m. In a mean value during vegetation period, R_t of the A was 40%-80% higher than other plantations, but no marked difference among others. Litter mass at forest floor in A was much lower, but soil organic matter (SOM) and root density were much higher , indicating this respiratory difference might be from SOM and root. Moreover,the partition of R_t to R_r, R_l and R_m varied with tree species. The contribution from R_r, R_l and R_m was respectively 41%, 19% and 40% in L, 40%, 29% and 27% in BL, 29%, 15% and 56% in A, 18%, 31% and 51% in S, 24%, 21% and 55% in K. Furthermore,respiration from soil microbes is less sensitive to temperature variation comparing to that of roots and litters. In conclusion, tree species could modify the partition of total respiration into the components of roots, litters and soil microbes and also their temperature sensitivity.

Key words: Soil respiration, Northeast China, temperature sensitivity, inter-species comparision