The Responses of Forest Fine Root Biomass/Necromass Ratio to Environmental Factors Depend on Mycorrhizal Type and Latitudinal Region. Issue 5 (30th May 2018)

• Record Type: Journal Article
• Authors: Wang, Cunguo; Chen, Zhao; Yin, Hong; Guo, Wei; Cao, Ying; Wang, Guojiao; Sun, Bei; Yan, Xuefei; Li, Jiandong; Zhao, Tian‐Hong; Brunner, Ivano; Dai, Guanhua; Zheng, Yixiang; Zheng, Yiguo; Zu, Weizhong; Li, Mai‐He
• Is Part Of: Journal of geophysical research. Volume 123:Issue 5(2018)
• Page Start: 1769
• Page End: 1788
• Publication Date: 2018-05-30
• Subjects: living fine root -- dead fine root -- climate change -- forest biome -- successional status -- mycorrhizal status; Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1029/2017JG004308
• Languages: English
• ISSNs: 2169-8953

Abstract

Abstract: Fine root (≤2 mm in diameter) biomass/necromass (B/N) ratio, representing many dynamic key root parameters, can serve as a powerful measure of root vitality. Based on a global synthesis of fine root biomass and necromass in forest ecosystems, we describe a framework for recognizing responses of B/N ratio to biotic (e.g., mycorrhizal type) and abiotic (e.g., latitudinal region) characteristics. Arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM) forests had similar average B/N ratios (3.28 versus 3.23). AM forest B/N ratio decreased with increasing altitude, stand density, tree age, and soil carbon/nitrogen ratio (C/N) but increased with soil pH. In contrast, ECM forest B/N ratio increased with increasing mean annual precipitation (MAP), altitude, and stand density but decreased with tree age. The average B/N ratio was higher in temperate forests (4.39) than in tropical (2.97) and boreal forests (2.40). The B/N ratio was relatively stable in temperate forests irrespective of changes in biotic and abiotic factors. In tropical forest, the B/N ratio was sensitive to mean annual temperature, altitude, soil C/N ratio, and pH, whereas in boreal forests, it was more sensitive to MAP, stand density, and tree age. The late‐successional forest B/N ratio was closely aligned with biotic and abiotic factors. Our analysis revealed that the relationships of B/N ratio with climate, topography, edaphic, and stand characteristics were dependent on mycorrhizal types and latitudinal regions. These findings provide a basis for large‐scale prediction of fine root dynamics and for better understanding of belowground processes of global forest ecosystems in a changing world. Key Points: Fine root biomass/necromass (B/N) ratio of forest ecosystems are synthesized at a global scale Arbuscular mycorrhiza and ectomycorrhiza forests have similar average fine root B/N ratio, and the average B/N ratio is higher in temperate forests than in tropical and boreal forests Mycorrhizal types and latitudinal regions influence the fine root B/N responses to climate, topography, edaphic, and stand properties