Heterotrophic Respiration and the Divergence of Productivity and Carbon Sequestration

Net primary productivity (NPP) and net ecosystem production (NEP) are often used interchangeably, as their difference, heterotrophic respiration (soil CO2 efflux, RSH = NPP−NEP), is assumed a near-fixed fraction of NPP. Here, we show, using range-wide replicated experimental study in loblolly pine (Pinus taeda) plantations that responds differently than NPP to fertilization drought treatments, leading the divergent responses NEP. Across natural range species, moderate (+11%) (−7%) combined such NEP increased nearly threefold ambient control 43% under treatment. A 13% decline led 26% increase while was unaltered. Such benefit for carbon sequestration twofold control, but disappeared fertilization. Carbon efficiency, NEP:NPP, varied among sites, up both