Associations between forest vegetation and the fertility of soil organic horizons in northwestern Russia

Abstract

Background: Being the product of the same environment, soil and vegetation are mutually associated with each other, but the relationships between edaphic properties and vegetation characteristics are still far from clear. Accordingly, the specific aim of this study is to identify relationships between forest site types/forest types and the fertility of soil organic horizons in northwestern Russia. The relationships were assessed at the level of three large forest regions, the northern and middle taiga of the Republic of Karelia, and the Karelian Isthmus (Leningrad region), based on 37 spruce, 66 pine, and 16 birch plots which were integrated with the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). Results: Soil forming rock and land-use history partly explain the differences in the fertility of soil organic horizons between the forest ecosystems in northwestern Russia. Climatic factors are closely correlated with plant species richness, density and the fertility of soil organic horizons. Nutrient content in the organic horizons increased from poor to rich site types identified according to composition of understory vegetation and the occurrence of certain indicator species, i.e. Cajander's forest site types. The most informative parameters in explaining differences between Cajander's types were nitrogen, carbon to nitrogen ratio, exchangeable calcium, magnesium, potassium, and base saturation. Extractable phosphorus, carbon to nitrogen ratio, exchangeable calcium, magnesium, aluminum and base saturation were the most informative parameters in explaining differences between forest types identified within the Cajander types in accordance with the tree species composition, i.e. Sukachev's forest types. The organic horizons of spruce and birch-dominated forests contained significantly more nutrients, compared to those dominated by pine. These differences were explained by differences in litter quality, and the crown shape and density of tree species, which affect the intensity of nutrient leaching. Conclusions: The study presents new findings regarding the relationships between forest sites/types and the fertility of soil organic horizons in northwestern Russia. Differences in organic horizon's fertility between the taiga subzones are explained by differences in the soil forming rock, climatic conditions, land-use history and shares of forest site types/forest types.

Site types revisited: Comparison of traditional Russian and Finnish classification systems for European boreal forests

“…The correspondence between certain types in the Cajanderian and Sukachevian system, as assumed by previous work (Sukhanov et al, 2014;Lukina et al, 2019b), appears to be true at least similarly to the correspondence between Cajander's forest site types in different vegetation zones within Finland. We must note, though, that the unequal sample sizes between the two countries and between site types in our data require that the results are interpreted with caution.…”

“…In summary, our results suggest that both Cajander's and Sukachev's site type classifications logically arrange the variation within the focal forests with respect to multiple characteristics — community composition, soil fertility, tree productivity, and biodiversity in the understorey — and do so in a similar way. The correspondence between certain types in the Cajanderian and Sukachevian system, as assumed by previous work (Sukhanov et al, 2014; Lukina et al, 2019b), appears to be true at least similarly to the correspondence between Cajander's forest site types in different vegetation zones within Finland. We must note, though, that the unequal sample sizes between the two countries and between site types in our data require that the results are interpreted with caution.…”

“…The tree stand was described in terms of tree species composition, and mean height, diameter at breast height, number of living trees, and total basal area were assessed (Tonteri et al, 2016; Lukina et al, 2019b). An estimate of total volume (m 3 /ha) was calculated based on these measurements.…”

“…This would mean, conversely, that Sukachev's types grouped by the understorey characterization would more or less correspond to Cajander's site types. This link between the two systems has been utilized in previous studies (Sukhanov et al, 2014; Lukina et al, 2019b), but has not been formally tested. More detailed information about the overlap between the two systems could facilitate transfer of information and forest management tools between Finland and Russia.…”

Effects of Urban Forest Types and Traits on Soil Organic Carbon Stock in Beijing

“…Moreover, SOC storage impacts the other ecological functions of soil as well, such as biomass production, nutrient and water-holding capacity, infiltration capacity and resistance to erosion, and providing habitats for biological activity [8,9]. Studies of forest groups and species characteristics affecting soil fertility parameters have been widely carried out in the non-urban environment [10], but less so in an urban context [11]. An in-depth understanding of the relationship between urban forest and SOC is key to maintain and enhance the quality of urban ecosystem services.…”