Clear-cutting effects on components of the carbon balance in a bilberry-type pine forest in southern Karelia

Abstract

Photosynthetic carbon flux and soil respiration are major determinants of the carbon balance of terrestrial ecosystems. Components of the carbon exchange of woody plants and soils were estimated in a 10-year-old clear-cut site of mid-boreal bilberry-type pine forest in southern Karelia during the warm season (July–August) in 2017–2019. The control was trees of the same age (10–15 years) and natural soils under the canopy of a mature bilberry pine forest. A comparison of the parameters of CO2 gas exchange in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), gray alder (Alnus incana (L.) Moench), and aspen (Populus tremula L.) revealed that photosynthetic uptake of CO2 exceeded its release by foliage during dark respiration in all the species more significantly in the regenerating clear-cutting (6–10-fold) than under mature stand canopy (3–6-fold). The rate of photosynthesis in trees of the same age was higher in deciduous species compared to pine both in the clear-cut site (16.6–17.6 and 7.4 μmol/m2·s) and under pine forest canopy (11.2–12.3 and 5.5 μmol/m2·s). The contributions of soil emission to the atmospheric СО2 flux in the regenerating clear-cutting (4.6 μmol/m2 s) and under the stand canopy (5.9 μmol/m2·s) are reported. Intra-seasonal variability of the parameters of carbon exchange in woody plants and soil was high as opposed to the relatively low variation among years in both sample plots.

Keywords

• logging
• natural forest regeneration
• со2 gas exchange in woody plants
• со2 emission from soil surface
• podzolic sandy soils
• environmental factors