SOIL RESPIRATION IN A POOR UPLAND SITE OF SCOTS PINE STAND SUBJECTED TO ELEVATED-TEMPERATURES AND ATMOSPHERIC CARBON CONCENTRATION

Soil respiration rates under elevated temperature and atmospheric CO2 concentrations were studied in eastern Finland (62 degrees 47'N, 30 degrees 58'E, 144 m.a.s.l.) around naturally regenerated 20 - 30 years old Scots pine trees, enclosed in open top chambers. The production of CO2 varied spatially and temporally, but clearly followed the changes in temperature measured at the soil surface. However, soil respiration in the open control was higher than that in chambers; i.e. the chamber itself changed the conditions by increasing the temperature, altering the movement of water, and thereby soil moisture, Nevertheless, an elevation in the concentration of atmospheric CO2 raised soil respiration and brought it nearer to the level in the open control. An increase in temperature seemed to inhibit this rise, possibly because of an imbalance between temperature and moisture.