One of the ways of helping to increase the amount of carbon in ecosystems is through restoration of degraded habitats. But what restoration strategies are best for healthy soils? Strategies include passive restoration (letting the native vegetation regrow naturally) and active restoration (like tree plantings). Differences in restoration strategy can lead to changes in forest characteristics, such as tree density, species richness, and soil properties, between passive and active restoration, which in turn may affect litter production and carbon sequestration.
“We have a limited understanding of how changes in biotic and abiotic conditions associated with different restoration strategies affect litterfall carbon and soil respiration.”
In a recently published study that forms part of Hoa’s thesis, she measured carbon fluxes (the carbon in litterfall and released in soil respiration) at locations that differed in land-use history and forest restoration strategy (planted and naturally regenerating) in Leptospermum scoparium (mānuka; Myrtaceae) forests.
She found that litterfall carbon in planted forests was more than double that of naturally regenerating forests. This is consistent with previous studies that show higher litter production in active than passive forest restoration strategies.
Furthermore, soil respiration was higher in planted than in naturally regenerating forests. This implies that planted forest soil is undergoing greater decomposition activity than naturally regenerating forest soils.
More work is required to understand whether these trends are true for other locations and forest types. Even so, this study lays the foundation for further comparative work between planted and naturally regenerating forest systems. Work like this is also important for understanding how resilient planted systems are to disturbances such as myrtle rust.
Hoa’s paper is available here: https://doi.org/10.1007/s11104-024-06844-y