Growth and drought resilience of four native tree species suitable for reforestation of Brazil’s Atlantic Forest

Abstract

Abstract Deforestation of tropical forests has been a critical issue affecting climate change mitigation and biodiversity conservation. Reforestation strives to remedy this situation, yet it is futile as long as deforestation of primary forests continues. Since deforestation is partly motivated by the demand for valuable tropical wood, reforestation should focus not only on planting native tree species, but specifically on a high diversity of native tree species with high-quality wood. However, the eco-physiological information required for growing such species is limited, and their resilience to drought events is unknown. Here, we focused on four native tropical wood tree species identified as suitable for Brazil’s Atlantic Forest reforestation. Growth, carbon assimilation, water-use and xylem hydraulics were studied in seedlings of the two legume species Dalbergia nigra and Plathymenia foliolosa and the two non-legume species Cariniana legalis and Zeyheria tuberculosa. Seedlings were monitored weekly for 9 consecutive weeks, three to five weeks of which under induced drought. Growth and carbon assimilation were 25–65 per cent higher in the legume vs. non-legume species. In turn, non-legume species mostly avoided the drought by stomatal closure, producing a 50 per cent higher water-use efficiency (WUE) compared with the legume species. The average water potential at 50 per cent stomatal conductivity (Ψgs50) for legume species was −2.6 MPa, whereas for non-legume species it was −0.85 MPa. Still, each species showed a unique set of responses, indicating different growth strategies under mesic and xeric conditions. Our results indicate a divergence among legume and non-legume species, driven by a trade-off between plant productivity (carbon assimilation and growth) and plant safety (stomatal regulation and WUE). All in all, the four species of juvenile potted plants demonstrated a high capacity for recovery from drought, which supports their potential role in future reforestation under climate change.