Soil Organic Carbon Stocks in Mixed-Deciduous and Coniferous Forests in Austria

Abstract

Question: We compared the soil organic carbon stock of the forests of an entire country. The objective of our research was establishing the differences between coniferous or deciduous forests with respect to soil carbon stocks. The question is relevant because coniferous forests are increasingly damaged by abiotic and biotic disturbances that are related to climate change. Deciduous forests are considered to be less vulnerable. Their soils are expected to be more persistent and reliable sinks for carbon dioxide.Methods: Soil data are available from the Austrian Forest Soil Survey. Soils have been sampled on sites of the Austrian Forest Inventory. The data were stratified according to geology (calcareous vs. silicatic bedrock), orientation of the slopes, and forest type (coniferous vs. mixed-deciduous forest). These data were used to establish ground truth of soil organic carbon stocks. Further, we had simulation results of a coupled forest growth/soil carbon model. The scenarios built on the results of the Forest Inventory 2007/09 and reflect a business-as-usual forest management vs. a climate-change adaptation scenario where forest managers replace coniferous with deciduous forests if site conditions permit it. The simulations were performed with the forest growth simulator CÂLDIS and the soil carbon model Yasso07.Results: Based on the Austrian Forest Soil Survey carbon stocks of coniferous forests were consistently higher than in mixed-deciduous forests. This result applies both for the organic litter layer and the mineral soil to a depth of 50 cm. The depth gradients of carbon were similar in both forest types. The simulation under a strong warming scenario showed an increase in the carbon stocks of soils when conifers are replaced by deciduous tree species. In the 150-year simulation the majority of forest sites will become suitable for deciduous forests. The build-up of a large soil organic carbon stock is driven by the stronger harvesting pressure on the remaining coniferous forests. Deciduous forests were in lesser demand and developed under a light forest intervention regime. However, toward the end of the century, when the temperature level is far above present levels, the soil organic carbon stocks declined.

Dynamics of Soil CO2 Efflux and Vertical CO2 Production in a European Beech and a Scots Pine Forest

“…Germany's National Forest Soil Inventory (NFSI) has shown that pine forests have significantly higher C stocks in the soil organic layer than beech and other deciduous forests but lower stocks in the mineral soil (Grüneberg et al, 2019). Similar results regarding carbon stocks were found in the Austrian Forest Soil Survey but without differences in their vertical gradients (Jandl et al, 2021). Reasons for this included different lignin contents and C/N ratios; moreover, litter from leaves and needles differ in decomposability, resulting in different SOC stocks in the organic layer and mineral soil, as well as in different humus forms and chemistry (Fischer et al, 2002;Leuschner et al, 2013;Vesterdal et al, 2013;Diers et al, 2021).…”

How to Optimize Carbon Sinks and Biodiversity in the Conversion of Norway Spruce to Beech Forests in Austria?

“…The effect also holds for the traditional Austrian beech mixtures, such as beech/spruce [117,118], beech/oak [119], beech/pine [120], and spruce/fir/beech [121]. Effects on soil carbon will, in general, also be similar to a change from spruce to beech when admixing beech into previously pure conifer forests [80,122]. The high competitiveness of beech results in the need for more intensive management in order to keep high-value timber from other trees.…”

Analysis of the Spatiotemporal Evolution of Carbon Budget and Carbon Compensation Zoning in the Core Area of the Yangtze River Delta Urban Agglomeration

“…(1) ECC (16) where G i , G represent the GDP of the ith county-level city and the whole region; C i , C represent the carbon emissions of the ith county-level city and the whole region. The coefficient is used to measure the contribution of regional carbon emissions and the economy.…”

“…Terrestrial ecosystems absorbed a net 31% of the carbon dioxide released by human activities over the same period from 2010 to 2019 [15]. The methods for calculating carbon sinks include the sample site inventory method [16], the eddy covariance method [17], the ecosystem process modeling method [18], the atmospheric inversion method [19]. With the rapid development of remote sensing in recent years, scholars often utilize land use data to estimate carbon sinks at different scales.…”