Can we experimentally manipulate total NSC pools in trees?

Yes we can, by changing carbon source-sink relationships in different ways. Enhancing sink strength can be achieved by repeatedly removing sinks (e.g., leaves) or increasing sink activity (e.g., respiration). Source strength (carbon assimilation) can be hampered with drought (stomatal conductance), shading (light energy) or CO₂ deprivation (substrate availability). Recent experiments have shown that only shading and CO₂ deprivation are viable tools to manipulate total NSC pools. Drought also reduces carbon remobilization and transport and hence affects NSC pools only locally. Manipulating source-sink relationships allows addressing important ecological questions like mortality mechanisms, carbon storage dynamics and carbon-nitrogen trade-offs in symbiotic relationships.