Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

Abstract

Abstract. This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-alpine region of southern Germany. The sites are separated by only ten kilometers, they share the same formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for two years (July 2010 to June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (−130 ± 31 and −300 ± 66 g C m−2 a−1 in the first and second year respectively) than the natural bog forest at Schechenfilz (−53 ± 28 and −73±38 g C m−2 a−1). The strong net CO2 uptake can be explained by the high gross primary productivity of the spruces that over-compensates the two times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger LAI of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source, if the whole life-cycle, since forest planting is considered. We determined the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. The estimate resulted in a strong carbon release of +156 t C ha−1 within the last 44 yr, means the spruces would need to grow for another 100 yr, at the current rate, to compensate the peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but consistent carbon sink for decades, which our results suggest is very robust regarding short-term changes of environmental factors.

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

“…At the SPRUCE study site, using a unique collar enclosure method (1.13 m 2 ) that excluded trees (but likely not tree roots) Hanson et al [] reported annual NEE ranging from a slight sink of −3.1 g C m −2 yr −1 in 2013 to a C source ranging from 21 to 65 g C m −2 yr −1 across 2011, 2012, and 2014 (our main year of measurement). Annual net CO 2 exchange for temperate bogs typically ranges from slight sources (10 g C m −2 yr −1 ) to slight sinks (−76 g C m −2 yr −1 ) depending on bog site and the variable environmental conditions including water table, snow cover, and day and nighttime temperatures [ Lafleur et al ., ; Sottocornola and Kiely , ; Hommeltenberg et al ., ; Hurkuck et al ., ].…”

Deriving Effective Soil Water Retention Characteristics from Shallow Water Table Fluctuations in Peatlands

“…The bog has a 5‐ to 6‐m‐thick peat layer mainly under permanently water‐saturated conditions. The peat substrate and current vegetation is dominated by sphagnum mosses, with spatially variable contributions of sedges, heather meadows, and bog pines (Hommeltenberg et al, 2014). Vegetation around the south monitoring well is only sphagnum moss.…”

“…The northern part of the bog was partly affected by peat cutting until the 1950s (Hommeltenberg et al, 2014). Because the peat cutting occurred only in parts, the peat layer is spatially variable, showing different stages of decomposition.…”

Aquatic DOC export from subarctic Atlantic blanket bog in Norway is controlled by seasalt deposition, temperature and precipitation

“…Many more studies have quantified NEE for peatlands, but not aquatic carbon export, i.e., in subarctic (Aurela et al 2002;Lund et al 2015), boreal (Aurela et al 2007(Aurela et al , 2009Peichl et al 2014;Sagerfors et al 2008), tropical (Hirano et al 2012;Mezbahuddin et al 2014), and temperate peatlands (Beetz et al 2013;Campbell et al 2014;Elsgaard et al 2012;Lund et al 2007;McVeigh et al 2014). Despite the lack of quantification of key components of NECB, several studies claimed to quantify the carbon sink strength of these peatlands (Campbell et al 2014;Hirano et al 2012;Hommeltenberg et al 2014).…”