Age-related NPP decline in trees is due to:
The workbook attributes age-related decline in tree net primary productivity to statements A, B, and C, but their contents are omitted. Established mechanisms include greater respiratory maintenance costs as living biomass increases, hydraulic limitation over longer transport paths, nutrient constraints, changing allocation, and reduced photosynthetic capacity or leaf-area efficiency. No single mechanism explains every species and stand. Because the three assertions are unavailable, their combined selection cannot be scientifically verified from this row alone. Net primary production equals gr
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17-19
