Regional variation in peatland carbon stock assessments, northern Ontario, Canada

•We estimated carbon stock among peatland types in northern Ontario.•Treed fens had the highest mean C stock while open bogs had the least.•Peat carbon stock varied among peatland types with a wider variability in treed bogs and fens relative to open bogs and fens.

Northern peatlands (those located in boreal and subarctic regions) are important components of global soil organic carbon (C) stock. Moreover, they are located in regions witnessing rapid changes in climate and becoming intensely scrutinized for industrial development and alternative energy generation. However, peat C stock is highly variable and little is known about its variability especially among peatland types. This is an issue because it makes the monitoring of peatland carbon stock complicated especially with the changing climatic conditions. Furthermore, it limits the opportunities to successfully estimate peatland C stock across regional scales. We estimated peat C stock using data from 1982 to 1985 from Ontario Geologic Survey field study of peatlands distributed across twelve sites in northern Ontario. Carbon stock (kg C m− 2) was estimated using the equation: carbon concentration on gravimetric basis × bulk density × peat depth. The peat sampling depth was about 1 m and had a total data point of around 203 points. Treed fens had the highest mean C stock ± SE of 223 ± 31 kg C m− 2 while open bogs had the lowest mean C stock ± SE of 157 ± 7 kg C m− 2. Mean C stock also varied among peatlands at regional level with the inter-quartile range of about 72-73 kg C m− 2 for open bogs and fens; and around 94-141 kg C m− 2 for treed bogs and fens respectively. Minimum detectable differences in C stock were also large, ranging from 50 to 113 kg C m− 2 for bogs and fens, respectively. The required sample size to detect 20% change in peat C at a power of 70% was more than double (212 plot) for fens than the number of sample plots (82) surveyed. This implies more sample size and information for fens is needed. This could potentially be achieved by the use of geospatial technology in deriving peatland biophysical information.