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Loggers need to control their appetite for slow-growing trees to spare the Amazon rainforest from deforestation.

A new study by Ph.D. student J. Aaron Hogan points to changes in tree composition in a long-term study site in French Guiana to sound the alarm.

"We're approaching a threshold where we're forced to make some difficult decisions," Hogan said. "Do we feed into demand for these tropical hardwoods? Or do we stick to our guns and say you can't log any more until this stand is regenerated."

Demand for dense, slow-growing tropical hardwoods has ballooned over time. In 2015, more than 4.2 million square feet of tropical timber was harvested, up from the 2.7 million square feet harvested in 2007, according to the study.

The wood, primarily from the South American Amazon, feeds a global industry that benefits timber processors in Asia and its ultimate consumers in the United States and Europe.

If loggers were to return to a particular area too quickly, it could put a strain on the tree species they covet the most.

"We want to use long-term data to inform their practices," Hogan said. "We think it can be done in a good fashion that creates jobs and creates resources that can be used by people. We just need to make sure we're not too quickly."

The study also calls into question the practice of culling less-favorable trees by poison girdling. Long-term data in the Paracou Forest Disturbance Experiment established by the French research center CIRAD revealed that such practices had the opposite effect, Hogan said. Girdling trees in fact spurred more saplings of the less desirable species to flourish.

Hogan's study was co-authored by International Center for Tropical Botany Director Christopher Baraloto and an international team of researchers. It was published recently in the journal Ecological Applications.

More information: J. Aaron Hogan et al. Understanding the recruitment response of juvenile Neotropical trees to logging intensity using functional traits, Ecological Applications (2018). DOI: 10.1002/eap.1776

Journal information: Ecological Applications