Carbon and nitrogen pools and mineralization rates in boreal forest soil after stump harvesting

Lilli Kaarakka, Riitta Hyvönen, Monika Strömgren, Marjo Palviainen, Tryggve Persson, Bengt A Olsson, Erno Launonen, Birgitta Vegerfors, Heljä-Sisko Helmisaari

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The use of forest-derived biomass has steadily increased in Finland and Sweden during the past decades leading to more intensive forest management practices in the region, such as whole-tree harvesting, both above- and belowground. Stump harvesting results in a direct removal of stump and coarse-root carbon (C) from the stand and can cause extensive soil disturbance, which has been suggested to increase C mineralization. In this study, the effects of stump harvesting on soil C and nitrogen (N) mineralization, and soil surface disturbance were studied in two different clear-felled Norway spruce (Picea abies) sites in Central Finland. The treatments were whole-tree harvesting (WTH, removal of stems and logging residues), and WTH and stump harvesting (WTH + S). Both sites, Honkola (2 stands) and Haukilahti (6 stands) were mounded. In both treatments, soil samples were taken from different soil layers down to a total depth of 20 cm in the mineral soil from (i) mounds, (ii) undisturbed soil and (iii) pits. The sampling was performed 11-12 years after treatments. Soil C and N mineralization rates were determined in laboratory incubation experiments. In addition, total C and N pools (g m(2)) were estimated for each disturbance class and soil layer. Soil C and N pools had a tendency to be lower following stump harvesting, but no statistically significant treatment effect was detected. Stump harvesting increased soil mixing as indicated by a significant decrease in C concentration in the mound disturbance class. There was no significant effect of stump harvesting on soil C mineralization rates. A combination of mineralization rates and soil pool data showed that field C mineralization (g CO2-C m(-2) yr(-1)) did not significantly differ between stands where stumps were removed or were retained. Further, stump harvesting did not seem to have any stimulating effect on soil CO2 efflux 11-12 years after treatment. (C) 2016 Elsevier B.V. All rights reserved.
Original languageEnglish
JournalForest Ecology and Management
Volume377
Pages (from-to)61-70
Number of pages10
ISSN0378-1127
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 4112 Forestry
  • Stump harvest
  • Bioenergy
  • Norway spruce
  • Forest soil
  • Soil carbon
  • NORWAY SPRUCE STANDS
  • SCOTS PINE
  • TREE GROWTH
  • SITE PREPARATION
  • SILVER BIRCH
  • REMOVAL
  • FINLAND
  • REGENERATION
  • SWEDEN
  • SLASH

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