Quick Recovery of Carbon Dioxide Exchanges in a Burned Black Spruce Forest in Interior Alaska

Abstract

Observations of carbon dioxide (CO 2 ) flux with the eddy covariance technique were conducted at a burned boreal forest site five years after a wildfire and at a mature forest site in Interior Alaska to investigate the effects of wildfire on CO 2 exchange in a boreal forest. Both gross primary productivity and ecosystem respiration were lower at the burned site. The lower amount of vegetation explains the lower gross primary productivity and ecosystem respiration at the burned site. The reduced soil organic layer at the burned site further explains the lower respiration. On an annual basis, the five-year-old burned site was a CO 2 sink, which indicated earlier recovery of CO 2 exchange compared to other burned boreal forests in North America reported in the literature. The quick recovery of net CO 2 exchange is associated with constrained heterotrophic respiration, rather than recovery of vegetation. Burn severity can be a key variable in determining CO 2 exchange during the early stage of succession after wildfire.

Autumn warming reduces the CO2 sink of a black spruce forest in interior Alaska based on a nine‐year eddy covariance measurement

“…The dominant tree species was black spruce (Picea mariana), forming a sparse canopy. Further site information is available in previous publications (Ueyama et al, 2006aKim et al, 2007;Iwata et al, 2010Iwata et al, , 2011Iwata et al, , 2012. Tree density was 4500 tree ha À1 .…”

Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

“…The largest control on the carbon cycle exerted by fires is the burn severity (Goulden et al, 2011;Iwata et al, 2011;Genet et al, 2013;Jafarov et al, 2013). An eddy covariance study of carbon exchange at a severely burned black spruce forest at the Poker Flat Research Range revealed the forest became a carbon sink within 5 years (Iwata et al, 2011). Despite the lower gross primary productivity, compared to other burned forest studies, respiration was also much lower because the fire consumed the organic soil layer.…”

Growing season and spatial variations of carbon fluxes of Arctic and boreal ecosystems in Alaska (USA)

“…The PFR site is a burned black spruce forest at the Poker Flat Research Range (Iwata et al 2011), located approximately 35 km northeast of Fairbanks. The forest experienced a severe stand-replacing fire in mid June of 2004, resulting in no living overstory trees and an understory of moss and shrubs that were almost completely burned.…”

“…For reprints of this Invited Feature, see footnote 1, p. 1743. 7 E-mail: miyabi-flux@muh.biglobe.ne.jp budget of the Arctic tundra (Oechel et al 1993, Kwon et al 2006, Huemmrich et al 2010, interannual climate variability on CO 2 (Harazono et al 2003, Ueyama et al 2006, Welp et al 2007) and energy Randerson, 2008, Iwata et al 2012) fluxes, the role of stand disturbance (Welp et al 2007, Liu and Randerson, 2008, Iwata et al 2011, and ecosystem acclimation to climate change (Oechel et al 2000). Even though those observations provide valuable site-level information across various tundra and boreal ecosystems, the net effect that small scale observations have on a regional scale is still unclear.…”

“…These studies found that GPP and RE were determined by climate-related variables but NEE was determined by disturbance history. While recent chronosequence studies have begun to elucidate the role of disturbance on CO 2 fluxes in boreal forests (Amiro et al 2010, Goulden et al 2010, our knowledge is still limited and the rate of recovery of CO 2 fluxes following disturbance is extremely variable and difficult to model (Iwata et al 2011).…”