Faster growth leads to a shorter lifespan in trees, according to a paper published in Nature Communications. The findings could have implications for predictions of how much carbon forests can store under climate change.
A relationship between faster tree growth rates and shorter tree lifespan has been shown in some trees, particularly in cold-adapted conifers, but whether this applies across species and climates has been disputed. Such a trade-off would be at odds with the use of tree growth rates as a proxy for carbon storage, and cast doubt on Earth system model predictions of global forest carbon storage.
Roel Brienen and colleagues analysed a large dataset of tree-ring data representing 110 tree species across all continents except Africa and Antarctica. They report that faster growth is linked to reduced tree lifespan both across and within tree species, and show that this is not due to covariance with climate or soil variables. Using model forest simulations based on data about the black spruce (Picea mariana), they further show that this trade-off has the potential to slow down or even reverse the global forest carbon sink in the future.
These findings challenge most predictions of future carbon storage in mature forests, casting doubt on the persistence of the global forest carbon sink in the coming decades. The authors call for efforts to integrate tree-growth lifespan trade-offs in process-based models of forest carbon dynamics.
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