Forest soils need decades to heal


Forest soils take need decades to recover from catastrophic fire events or logging, significantly longer than previously thought, according to new research released by the Australian National University (ANU).

The study’s lead researcher Elle Bowd said that her team found that forest soils recovered over a period of 80 years from a bushfire event and 30 years after logging.

"We discovered that both natural and human disturbances can have incredibly long-lasting effects on forest soils that could impact plant communities and ecosystem function," said Ms Bowd, who is the lead author of the ANU team's Nature Geoscience paper. Professor David Lindenmayer, also from the ANU team, said scientists had not known how long soils were impacted by bushfires and logging prior to this study. "We thought forests could recover within 10 or 15 years, at most, after these sorts of events," said Professor Lindenmayer from the ANU Fenner School of Environment and Society. "Almost 99 per cent of Victoria's Mountain Ash forests have either been logged or burnt in the past 80 years, so these forests are facing a huge uphill battle to restore themselves to their former glory." The team collected 729 soil cores from 81 sites exposed to nine different disturbance histories in the Victorian Mountain Ash forests. These forests generate nearly all of the water for the five million people living in Melbourne, store large amounts of biomass carbon and support timber, pulpwood and tourism industries. "It's very likely that other forests around the world are facing similarly big challenges in terms of soil recovery following bushfires and logging," Ms Bowd said. "Soil temperatures can exceed 500 degrees Celsius during high-intensity fires and can result in the loss of soil nutrients. "Logging can expose the forest floor, compact soils, and alter soil structure, reducing vital soil nutrients. These declines are more severe in areas that have experienced multiple fires and logging."

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