Canadian Forest Service Publications

Large Soil Carbon Storage in Terrestrial Ecosystems of Canada

Year: 2022

Issued by: Pacific Forestry Centre

Catalog ID: 40602

Language: English

Availability: PDF (request by e-mail)

Mark record

Abstract

Terrestrial ecosystems of Canada store a large amount of organic carbon (C) in soils, peats and plant materials, yet little is known about the C stock size and distributions, both spatially and in various C pools. As temperature rises, C is becoming available for disturbance, decomposition and eventual release into the atmosphere, which makes the quantification of C stocks in terrestrial ecosystems of Canada of high interest for the assessment of climate change impacts and conservation efforts. We used a large number of field measurements, multisource satellite, climate and topographic data and a machine learning algorithm to produce the first wall-to-wall estimates of C stocks and uncertainties in plants and soils of Canada at 250 m spatial resolution. Our findings show that above and belowground live biomass and detritus store a total of 21.1 Pg of carbon (Pg C). Whereas the Canadian soils store 306 (±147, 90% confidence interval) Pg organic C in the top 1 m, 98 Pg C of which are stored in peatlands, confirming that the soil organic C dominates terrestrial carbon stocks in Canada. We also find previously under-reported large soil organic C stocks in forested peatlands on the boreal shields of Canada. Given that Canada is warming twice the global average rate and Canadian soils store approximately 20.4% of world soil C stocks in top 1 m, initiatives to understand their vulnerabilities to climate change and disturbance are indispensable not only for Canada but also for the global C cycle.

Plain Language Summary

Soil and plants of Canada store a large amount of organic carbon (C), yet little is known about the C stock size and distributions over the country. As temperature rises, more C is being released into the atmosphere, which makes the quantification of C stocks in soil and plants of Canada of high interest for the assessment of climate change impacts and conservation efforts. Here, we use satellite data and machine-learning models to produce the first maps of C stocks in plants and soils of Canada. We determined that Canadian forests store around 6% of all the carbon stored in the world's forests. Whereas the Canadian soils store 20% of world soil C stocks in top 1 m, confirming that soil organic C dominates terrestrial carbon stocks. We also find previously under-reported large soil organic C stock in forested peatlands on the boreal shields of Canada. Given that Canada is warming twice the global average rate, initiatives to understand their vulnerabilities to climate change and disturbance are indispensable not only for Canada but also for the global C budget and cycle.