What Characteristics of Soil Fertility Can Improve in Mixed Stands of Scots Pine and European Beech Compared with Monospecific Stands?

ABSTRACT

According to the current trends in forest management, endeavors are made to adjust the species composition to the site conditions and to increase the biodiversity. Changes in the species composition of forest stands lead to modifications of soil properties and nutrients cycle. The objective of the study was to evaluate the effect of monocultures (beech and pine) and mixed-species stands (pine-beech) on soil properties, particularly accumulation of soil organic carbon. We aim to demonstrate how different vegetation types influence soil properties in surface horizons of soil. The study sites are located in Germany and Poland under different tree stands Pinus sylvestris L., Fagus sylvatica L., and mixed-species stand. Contents of organic carbon and nitrogen, pH, and soil texture were analyzed. The studies conducted confirmed the positive effect of beech and mixed-species stands on acidification of surface soil horizons. We ordered the stands tested according to acidification effect on soils: pine stand > mixed stand > beech stand, which is consistent with previous studies. The most beneficial impact on the accumulation of organic carbon was observed in mixed-species stands in which beech and pine were found. Lower carbon-to-nitrogen (C/N) ratios confirm the high rate of organic matter decomposition and lower C/N ratio was reported in soil under beech stand in comparison to pine stands.

KEYWORDS:

• Beech stands
• forest soil properties
• mixed-species stands
• pine stands
• soil organic carbon

Acknowledgments

The networking in this study has been supported by COST Action FP1206 EuMIXFOR. All contributors thank their national funding institutions and the woodland owners for agreeing to establish, measure, and analyze data from the triplets. The last author also thanks the Bayerischen Staatsforsten (BaySF) for supporting the establishment of the plots and the Bavarian State Ministry for Nutrition, Agriculture, and Forestry for permanent support of the project W 07 ”Long-term experimental plots for forest growth and yield research“ (# 7831-22209-2013).