Experimental drought increased the belowground sink strength towards higher topsoil organic carbon stocks in a temperate mature forest

Drought response of above and belowground carbon flux dynamics and soil organic carbon (SOC) stocks of the two most important tree species in Europe following five years of simulated summer drought. The differently-sized arrows represent carbon flux sizes and directions (WEOC: water-extractable organic carbon: blue, root exudates: yellow, net assimilation: green, SOC: soil organic carbon stock: brown). SOC stocks increased under P. abies but not under F. sylvatica. Under both species, SOC accumulated in the mineral topsoil and showed patterns of contrasting changes in soil organic matter stability.