Productivity and humus status of forest soils in Estonia

Abstract

The annual phytoproductivity (APP) of the main Estonian postlithogenic mineral soils ( Leptosols, Cambisols, Luvisols, Albeluvisols, Podzols and Gleysols), which form 61.3% of the areas covered with forest, was analysed. The quantitative data on soil cover properties and plant cover (phytocoenosis) productivity originates from the database PEDON, which consists of 195 research areas on soils mentioned above. The APP was determined for stems of trees (APPs; n=195) and for the whole part of vegetation aboveground (APPa; n=79). The total annual phytoproductivity (APPt) was calculated indirectly for nine soil groups using allometric relationships suitable for different ecosystem types, as well as by formulas for determining APPt after soil group positions on the scales of moisture conditions and soil mineral–chemical composition (or throphic condition) on the Estonian soil ordination net. Relationships between soil groups and forest site types as well as humus cover types were also developed. In the frigid udic (49%), frigid aquic (47%) and frigid aridic (4%) pedoclimatic conditions, the APPa varied from 2.8 to 14.5 Mg ha −1. The highest productivity (10.4±1.4 Mg ha −1) was obtained for Luvisols. The dominating forest site type on these soils is Aegopodium and Hepatica and the prevalent humus cover type is moist and fresh moder- mull. Epigleyic and Fibrihistic Podzols have the lowest productivity (3.7±0.5 Mg ha −1) where the forest site type was Vaccinium and the humus cover type was peaty mor. The site productivity was determined first of all by pools of physical clay in solum and metric layer of soil cover. The pools of organic matter did not show a notable positive correlation with soil productivity. For the sustainable management of forest areas, it is important to contribute to the formation of stabilised forest ecosystems by achieving adequacy between the forest vegetation and site characteristics.