Chin J Plan Ecolo ›› 2018, Vol. 42 ›› Issue (9): 955-962.DOI: 10.17521/cjpe.2018.0080

• Review • Previous Articles     Next Articles

Decomposition of different root branch orders and its dominant controlling factors in four temperate tree species

GU Wei-Ping1,LIU Rui-Peng1,LI Xing-Huan1,SUN Tao2,ZHANG Zi-Jia2,ZAN Peng1,WEN Lu-Ning1,MA Peng-Yu1,MAO Zi-Jun1,*()   

  1. 1 Key Laboratory of Forest Plant Ecology. Ministry of Education, Northeast Forestry University, Harbin 150040, China
    2 Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2018-04-10 Revised:2018-09-10 Online:2018-09-20 Published:2019-01-15
  • Contact: Zi-Jun MAO
  • Supported by:
    Supported by the National Natural Science Foundation of China.;Supported by the National Natural Science Foundation of China.(31500361);Supported by the National Natural Science Foundation of China.(31700397);the Special Funds for Basic Scientific Research Business Expenses of Central Colleges and Universities.((2572017AA21))

Abstract:

Aims Fine root decomposition is the major pathway of carbon and nutrient input to the soil in forest ecosystems. However, the patterns and controlling factors of the decomposition of these roots, especially the finest roots, are poorly understood.

Methods Using a root branch-order classification, we separated the first four orders of fine root systems of Pinus koraiensis, Larix gmelinii, Fraxinus mandschurica and Betula platyphylla into two classes: first- and second-?order roots combined into lower-order; third- and fourth-order roots combined into higher-order. We conducted a four-year field litterbag study on decomposition of these four root orders of four temperate tree species in northeast China.

Important findings The results showed that the lower-order and higher-order roots had a decomposition rate constant of 0.342 and 0.461 for Pinus koraiensis, 0.304 and 0.436 for Larix gmelinii, 0.450 and 0.555 for Fraxinus mandschurica, and 0.441 and 0.579 for Betula platyphylla, respectively. We observed slower decay rates in lower-order than in higher-order roots in all four studied tree species. The root decay constants (k) was significantly correlated with both acid-unhydrolyzable fraction (AUF) and total non-structural carbohydrate (TNC). We concluded that slow decomposition of lower-order roots was mainly driven by their high AUF and low TNC concentrations.

Key words: fine-root decomposition, root order, acid-unhydrolyzable fraction, non-structural carbohydrate, temperate tree species