Ecosystem carbon storage two decades after afforestation in Norway spruce and silver birch monocultures and mixtures on abandoned agricultural land in hemiboreal Estonia
Year: 2024
Type: article
Abstract: In silviculture, tree species mixing is seen as a potential measure to increase ecosystem carbon (C) sequestration due to higher resulting productivity compared to monocultures. Currently, there is a lack of studies on how monocultures and mixtures of the two main boreal tree species, Norway spruce and silver birch, compare regarding C sequestration and storage in planted stands. We evaluated ecosystem C stocks, stand productivity and soil nutritional status in spruce and birch monocultures as well as mixed stands with 50/50 mixing proportion two decades after afforestation of abandoned agricultural lands with homogeneous soil fertility. We found that Norway spruce monocultures had the highest mean annual increment (MAI), highest ecosystem C stock, and the highest periodic annual increment (PAI). In silver birch stands, C was mostly stored in the stems of the trees, whereas Norway spruce monocultures had a significantly higher share of C stored in the canopy. While the growth of individual silver birches was not influenced by the stand type, Norway spruce was suppressed by the inter-specific competition in the mixtures, where the average tree stem MAI was 56 % lower than in the monocultures. In general, the SOC and soil nutrient concentrations were similar in the mixed-species stands and monocultures. Spruce monocultures had a higher SOC stock in the forest floor. In conclusion, we did not confirm a higher productivity of mixed stands compared to monocultures, but different patterns of C allocations indicate the need for longer observations to identify the silvicultural system with the best climate benefit. • Mixed forests are favored over monocultures in the changing climate. • Productivity and C storage advantages of mixtures are unclear in Northern Europe. • We studied silver birch and Norway spruce monocultures and mixtures. • The highest productivity and C stocks were found in spruce monoculture. • Ecosystem C stock allocation differed between studied stand types.
Source: Forest Ecology and Management
Institutions: Estonian University of Life Sciences, University of Tartu
Language: English
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
SDGs: Life on land, Climate action
Open Access status: hybrid
Estimated APC paid: $3,460
OpenAlex ID: W4405114642