Soil respiration and nitrogen leaching decreased in grey alder (Alnus incana (L.) Moench) coppice after clear-cut

ABSTRACT

Grey alder (Alnus incana) is a highly productive indigenous tree species, potential for short-rotation forestry in the Baltic and Nordic countries. The aim of the study was to investigate the development of a new forest generation, as well as the nitrogen (N) and carbon (C) storages and fluxes in a grey alder regenerating coppice (COP) after clear-cut and in an adjacent unharvested 21-year-old stand (MAT), which had reached its bulk maturity. The regeneration of COP was rapid and 5 years after clear-cut, stem mass was 6.4 t ha⁻¹. The nitrogen demand of the aboveground part of the 5-year-old COP trees was estimated to be roughly half of the corresponding value for MAT, depending mostly on leaf production. The annual N leaching flux in MAT was in the range of 16–29 kg ha⁻¹, the corresponding values for COP were roughly half of that. Net nitrogen mineralization did not differ significantly between MAT (117 kg ha⁻¹) and COP (129 kg ha⁻¹). For the soil respiration study, a 32-year-old grey alder stand growing at a similar site was included; soil respiration was significantly higher in MAT compared to COP in all study years in both studied stands.

KEYWORDS:

• Alnus incana
• nitrogen
• soil respiration
• clear-cut
• biomass production
• leaching

Acknowledgements

This work was supported by the Estonian Science Foundation grant number 9342; by the Institutional Research Funding IUT21-04, IUT34-9 of the Estonian Ministry of Education and Research and by R&D project No. P170053MIMK of the Estonian University of Life Sciences, as well as by the projects of Environmental Investment Centre Nos. 11-10-8/196 and 3406. We thank Mrs. Ester Jaigma for revising the English text of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Jürgen Aosaar http://orcid.org/0000-0002-7711-2014

Mats Varik http://orcid.org/0000-0002-6633-1967

Hardo Becker http://orcid.org/0000-0002-1150-4808

Gunnar Morozov http://orcid.org/0000-0002-9442-9929

Mai Kukumägi http://orcid.org/0000-0002-2313-148X

Additional information

Funding

This work was supported by the Estonian Science Foundation grant number 9342; by the Institutional Research Funding IUT21-04, IUT34-9 of the Estonian Ministry of Education and Research, by R&D project No. P170053MIMK of the Estonian University of Life Sciences, as well as by the projects of Environmental Investment Centre Nos. 11-10-8/196 and 3406.