The contribution of planted forests to regional carbon storage: evidence from western Hunan, China (1990-2020).

UNLABELLED: The widespread expansion of planted forests, fueled by initiatives such as China’s Grain-for-Green Program, plays a critical role in climate mitigation, yet its carbon performance compared to natural forests remains contested. Using​ spatiotemporal analysis, this study systematically ​examines​ the dynamics of planted and natural forests in the western region of Hunan from 1990 to 2020, and ​assesses​ their impacts on regional carbon storage. The results reveal a marked forest transition: while natural forests declined, planted forests expanded considerably, creating a distinct spatial trade-off—planted forests proliferated mainly at mid-low elevations (300–700 m), whereas natural forests were largely confined to higher elevations (400–900 m). Although natural forests stored more carbon overall (55.1% of the regional total), planted forests exhibited superior carbon sequestration rates per unit area.​​ Notably, newly established planted forests on converted land accumulated almost equivalent carbon stocks (19.0 Tg C) to older, stable natural forests (19.5 Tg C), highlighting their rapid carbon uptake potential. Spatiotemporal analysis confirmed that ​conversion of cropland was the dominant pathway, driving both the expansion of planted forests and the associated carbon gains. These findings ​quantify the net carbon gain from restoration policies​ and underscore that future land-use strategies must ​manage their spatial trade-off​ to secure long-term climate and ecological benefits.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13021-026-00443-3.