Decomposition of Scots pine fine woody debris in boreal conditions: Implications for estimating carbon pools and fluxes

Soil warming accelerates decomposition of fine woody debris

“…Standard error is in parenthesis in both tables Acer saccharum 18 (2) 11 (1) 13 (1) 8 (1) Betula lenta 19 (2) 14 (1) 14 (1) 9 (1) Quercus rubra 26 (3) 16 (2) 16 (1) 11 (1) Tsuga canadensis 41 (6) 29 (5) 25 (4) 15 (1) Our research, in conjunction with others (Tritton 1980;Mattson et al 1987;Vávřová et al 2009), supports the prediction that debris size will influence decomposition under ambient conditions, with smaller debris decomposing faster than larger debris. Though our analysis fits the literature well, our decay constant and the estimated time of 95% mass loss was based on only 2 years of data.…”

“…Several studies found that both temperature and moisture availability (through internal wood moisture content or precipitation) increased decomposition (Wang et al 2002;Garrett et al 2007;Vávřová et al 2009;Wu et al 2010). Specifically, moisture levels below 30% can hinder fungal growth (Kaarik 1974).…”

“…The magnitude of a change in decomposition due to warmer temperatures may be mitigated by quality, as determined by the biochemical complexity of the debris (Aber and Melillo 2001), and the size of FWD, as both have been shown to slow decomposition. While some studies have investigated the effect of debris quality and size on decomposition of FWD (Vávřová et al 2009;Fasth et al 2011;Tuomi et al 2011), few have simultaneously examined how these factors will interact with warming in an experimental field setting. As a result, it is not clear how much warming will speed decomposition from this carbon pool or what factors could mitigate this mass loss.…”

“…Debris quality is important to our understanding of FWD decomposition (Cornelissen 1996;Vávřová et al 2009;Yang et al 2010). Characterized from the microbe's perspective, litter quality is defined by the accessibility of carbon molecules (Couteaux et al 1995).…”

“…Indeed, several studies on FWD have found an inverse relationship between debris diameter and decomposition down to 3 cm in diameter (Tuomi et al 2011) and less (Muller-Using and Bartsch 2009). Vávřová et al (2009) attributed this relationship to higher amounts of labile, soluble components in smaller debris, making it easier to decompose. The interaction of quality and debris size may be more complex though, as Fasth et al (2011) found that certain species with decay resistant heartwood had an inverted size effect (decomposition rate increased with size).…”