Primary Productivity Determinants of Different Land Uses in Humid Subtropical Ecosystems: From Native Forests to Tree Plantations

DE DIEGO, M. S.; SCHOLZ, F.; CRISTIANO, P. M.; BUCCI, S. J.; DIAZ VILLA, M. V. E.; RODRÍGUEZ, S. A.; GOLDSTEIN, G.

ECOSYSTEMS (NEW YORK. PRINT)

SPRINGER

Año: 2020 vol. 24 p. 481 - 501

1432-9840

Land-use changes in forest ecosystems may alterthe amount of carbon sequestration. The mainobjective of this study was to characterize the impactof different land-use practices on structure andfunctioning of humid subtropical forests that areunder severe threat. We emphasize the characterizationof canopy photosynthetic activity, assessedby the Enhanced Vegetation Index (EVI), the LeafArea Index (LAI) and the fraction of AbsorbedPhotosynthetically Active Radiation (fPAR), using acombination of ground base measurements andremote sensing data on native well-preserved forests,impacted forests by selective logging and pineplantations in NE Argentina. Even though selectivetimber extraction resulted in a substantial decreasein stand?s tree density, EVI values were as high asthose from preserved forests. In these forests, anincrease in the understory cover appears to compensatethe response of stand?s EVI to timberextraction. Removal of canopy trees enhancesincoming solar radiation, allowing active growth ofunderstory vegetation. The pine plantationsexhibited the lowest values of LAI, fPAR and EVI.However, when EVI was normalized by LAI, thepine plantations exhibited the highest EVI/LAIvalues. Our results suggest that after 15 years offorest recovery from selective timber extraction,photosynthetic capacity was similar to that of preservedforests. Increases in the understory covermay compensate the potential decrease in the canopyphotosynthetic activity. Pine plantations resultedin substantially lower productivity asdepicted by lower EVI and LAI but exhibited highergrowth efficiency than native forests.