PARENT SESSION
Oral Session #40: Carbon sequestration and flux.
Presiding: G. Koch
Tuesday, August 6. 1:00 PM to 4:45 PM. Gila Meeting Room, TCC.
Estimating forest fine root biomass and production from aboveground measurements: A new paradigm.
Chen, Wenjun*,1, 1 Canada Centre for Remote Sensing, Ottawa, Ontario, Canada
ABSTRACT- Fine root productivity often exceeds aboveground production in forest ecosystems, despite the fact that live fine root biomass constitutes only a small fraction of total stand biomass. Fine roots of forest ecosystems also carry out the critical functions of acquisition of nutrient and water from soil. Whereas many studies have been devoted to the quantification of fine root biomass and production, it remains a difficult problem, especially with regarding the scaling up from a site measurement to landscape scales. Attempts have been made to relate fine root biomass to other variables, such as to total root biomass via the ratio of fine root to total root biomass, and to foliage biomass. Yet, whereas relationship between total root biomass and the ratio of fine root to total root are statistically significant, there is not good relationship between fine root and total root. Lack of simultaneously measurements of fine root and foliage, and the large variation of the ratio of fine root biomass to foliage biomass limit the usefulness of the latter approach. In this study, we will introduce a new paradigm for estimating fine root biomass and productions, by analysing fine root biomass at the tree level, instead of the usual stand level. Data of fine root biomass and production in over 200 boreal and temperate forest stands were collected from literature and unpublished sources. To reduce the errors caused by the mix of forest fine roots and understory fine roots and the difference in the definition of fine roots that ranges from <0.5 mm to <10 mm, we first separate the contribution of forest to fine root from that of understory, and use a single fine root definition. We will present the initial results of this study and discuss the strength and shortcoming of the new approach.
KEY WORDS: fine root, biomass, production, estimation