Canadian Forest Service Publications

Are mosses required to accurately predict upland black spruce forest soil carbon in national-scale forest C accounting models? 2013. Bona, K.A.; Fyles, J.W.; Shaw, C.; Kurz, W.A. Ecosystems 16(6): 1071-1086.

Year: 2013

Issued by: Northern Forestry Centre

Catalog ID: 34951

Language: English

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Available from the Journal's Web site.
DOI: 10.1007/s10021-013-9668-x

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The boreal forest plays a key role in the global carbon (C) cycle, and black spruce (Picea mariana (Mill.) BSP) forests are the dominant coniferous forest type in the Canadian boreal forest. National-scale forest C models currently do not account for the contribution of moss-derived organic matter that we hypothesize to be significant in the C budget of black spruce ecosystems. One such model, the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3), is designed to meet Canada’s forest-related greenhouse gas reporting requirements. In this study our goal was to determine if black spruce forest soil C stocks are significantly underestimated by the CBM-CFS3, and if so, to determine if estimates could be improved by adding moss-derived C. We conclude that in black spruce sites, organic layer C is significantly underestimated by CBM-CFS3 compared to sites with all other leading tree species analyzed. We compiled and used published moss net primary productivity rates for upland forest systems, with decomposition rates, in mass-balance calculations to estimate mean moss-derived C in black spruce forests for feather mosses at 64 Mg C ha-1), and for sphagnum mosses at 103 Mg C ha-1). These C pools are similar to the CBM-CFS3 mean underestimation of black spruce soil organic layers (63 Mg C ha-1). We conclude that the contribution of mosses is sufficiently large that a moss C pool should be added to national-scale models including the CBM-CFS3, to reduce uncertainties in boreal forest C budget estimation. Feather and sphagnum mosses should be parameterized separately.

Plain Language Summary

Live and dead moss layers occur in many of Canada’s forests and can contain large amounts of carbon. Carbon dioxide, a greenhouse gas, is used by mosses to grow and is stored as carbon in mosses for a long time, which reduces greenhouse gases. Mosses can also burn in forest fires and add to greenhouse gases. The computer model that calculates the amount of carbon and the greenhouse gas balance for Canada’s managed forests does not include mosses; we wanted to know if including mosses would improve the model’s ability to calculate the total amount of carbon in forests where mosses occur. We found that it did, especially if separate calculations were used for different types of mosses. This work is an important first step towards including mosses in the computer model to better calculate the contribution of mosses in forests to the greenhouse gas balance of Canada.