Non-native conifers grow faster in the Southern Hemisphere, but bring ecological risks - Space and astronomy

A study of 192 sites across four continents found that Northern Hemisphere conifers planted in the Southern Hemisphere can grow up to four times faster and show greater drought resistance. Researchers say the finding could support carbon-storage efforts, while warning that plantations may threaten native habitats and increase fire risks.

Researchers studying conifers across 192 sites on four continents found that pines, spruces, firs, cedars and related trees planted in the Southern Hemisphere often grow much faster and withstand drought better than trees growing within their native ranges. The findings were published in Nature.

Northern Hemisphere conifers growing in the Southern Hemisphere had higher concentrations of carbohydrates, including sugars and starches. These carbon reserves may provide energy during stressful seasons and help explain the trees’ drought resilience.

The result challenges the expected trade-off between rapid growth and tolerance of stressful conditions, according to Stephen Brewer, an ecologist at the University of Mississippi and one of the study’s researchers. The combination could make such trees attractive for afforestation projects intended to remove carbon from the atmosphere, since effective carbon sinks need to grow quickly and survive drought.

However, the researchers cautioned against treating non-native conifers as a simple solution. Plantations of species such as pines and Douglas firs have been established in Chile, Brazil and South Africa for the lumber industry, even though those trees do not naturally occur in the Southern Hemisphere. In some cases, the trees have spread beyond plantations into native ecosystems.

Brewer said pines have expanded into Brazil’s Cerrado, a savanna where they can grow rapidly and displace native vegetation. The researchers also pointed to potential fire risks associated with dense plantations in fire-prone landscapes.

A similar concern has emerged in Mississippi, where the timber industry began replacing longleaf pines with faster-growing slash pines in the 1930s. Both species are native to the state, but longleaf pines are more resistant to fire. Wildfires can destroy entire stands of slash pines, prompting foresters and nonprofit organizations to restore longleaf pine forests.

The study identified a possible alternative among native Southern Hemisphere trees. Species in the Nothofagus genus, commonly known as southern beeches, performed relatively well in both growth and drought-tolerance measures. Researcher Alex Fajardo said they could offer a more sustainable option for some afforestation efforts.

The study, titled “Pines grow faster and are more drought resilient in the Southern Hemisphere,” was authored by Alex Fajardo and colleagues and published in Nature. Its DOI is 10.1038/s41586-026-10969-8.

Sources: Phys.org.