Responses of soil carbon and nitrogen transformations to stump removal

Abstract

We studied in central Finland whether stump harvesting after clear felling of coniferous forest poses further short-term changes in soil carbon and nitrogen dynamics when compared to the traditional site preparation method, mounding. Exposed mineral soil patches in Norway spruce (Picea abies) dominated clear-cut stands were sampled 1–5 years after the treatments. The extent of the exposed mineral soil surface was significantly larger at the stump removal sites when compared to the mounding sites. No differences were found in soil pH, organic matter content or total concentration of soil C between the treatments or treatment years. Total concentration of soil N was consistently higher and C:N ratio lower in the stump removal plots than in the mounded plots. Further, both net N mineralisation and nitrification were clearly increased in the stump removal plots one year after the treatments. Soil microbial activity (CO production) was higher in the stump removal plots but similar difference was not found in sieved soil samples incubated in the laboratory. Fluxes of other important greenhouse gases (CH and NO) did not seem to be affected by stump removal. The differences between the stump removal and mounding procedures were most obviously attributed to more substantial soil disturbance by stump pulling and/or differences in the microbial communities and quality of soil organic matter in the differently treated soil.242

Biomass resource and environmental effects of Norway spruce (Picea abies) stump harvesting: An Estonian case study

“…Stump lifting may affect also nutrient transformation processes in the soil e.g. nitrogen mineralization (Kataja-aho et al, 2012). In the case of conventional harvesting, stumps are left in the clear-cut and the nutrients released during the decay of the stumps will be available to the next forest generation (Palviainen et al, 2010).…”

“…On the other hand, soil disturbance may induce more intensive mineralization of C and thereby initiate CO 2 emission, which may reduce the stable soil C storage (Grelle et al, 2012). Emission of CO 2 may be higher from stump removal plots compared to mounded plots, which can be attributed to more extensive soil mixing (Kataja-aho et al, 2012). Our results support the assumption that CO 2 emissions from uprooted areas decrease: at the Rõuge study site annual cumulative heterotrophic respiration was lower in the harvested area than in the control plot (1.8 and 2.5 t C ha À1 yr À1 , respectively), indicating reduced CO 2 emission because of the absence of decomposing stump biomass.…”

“…Recently, several papers that consider the issue of the potential environmental impacts of stump harvesting have been published in Europe (Walmsley and Godbold, 2010;Grelle et al, 2012;Kataja-aho et al, 2012;Eklöf et al, 2013;Hellsten et al, 2013;Iwald et al, 2013), however, the results of these studies are often contradictory. Some authors have found negative consequences of the removal of stumps for environment (Eklöf et al, 2013), while others have not detected serious negative effects (Hope, 2007).…”

Effect of stump size and timing of stump harvesting on ground disturbance and root breakage diameter

“…methylmercury, from sites due to the ground disturbance as it increases mineralisation (Egnell et al 2007). The documented knowledge about ground disturbance after stump harvesting is however limited, and it has only been studied in relation to the total disturbance on the site, which can vary between 40-70% of the area (Hope 2007;Kataja-aho et al 2012). Soil preparation is mainly performed using separate machines after the stumps have been harvested and forwarded (Kärhä 2012).…”

Ecosystem carbon (CO2 and CH4) fluxes of a Populus dettoides plantation in subtropical China during and post clear-cutting

“…Additionally, the removal of trees would decrease the transpiration from the deep soil, resulting in a relative higher soil moisture that promotes CH 4 production (Castro et al, 2000;Wu et al, 2011). The harvest residue effect on F CH4 was not examined at our site although previous studies indicated that stump removal did not have significant effects on CH 4 flux (Kataja-aho et al, 2012;Sundqvist et al, 2014) and aboveground logging residue had no change on F CH4 (Mäkiranta et al, 2012).…”