Link: https://academic.oup.com/treephys/article/27/1/115/1674502
Summary: The researchers tested the hypothesis that changes in net ecosystem productivity during aging of coastal Douglas-fir forests could be explained by changes in nutrient uptake, declines in canopy water, and changes in the ratio of autotrophic respiration to gross primary productivity. The paper quantifies the post-harvest emissions from the decay of logging residues, which can last 10-15 years.
Key excerpts:
- “Many forest ecosystems lose more C from heterotrophic and autotrophic respiration (Rh and Ra) than they gain from CO2 fixation (= gross primary productivity GPP) for several years after a stand-replacing disturbance…”.
- “This period of net C loss (when net ecosystem productivity (NEP = GPP – Ra – Rh) is negative) may continue for 10 years or longer in Canadian forests (Kurz and Apps 1999, Litvak et al. 2003), for at least 14 years in Siberian pine forests (Schulze et al. 1999), and for 14 (Janisch and Harmon 2002) or 20 (Cohen et al. 1996) years in coniferous forests of the Pacific Northwest.”
- “During the first 4 years after clearcutting, rapid Rh from fine and coarse litter raised ecosystem respiration Re (= Ra + Rh) while GPP remained low, so that estimated and modeled NEP (= GPP–Re) indicated net C losses of 500 to 750 g Cm– 2 year–1.”