Natural forest regeneration could be up to 96 per cent cheaper than traditional tree-planting programs, a global study involving the universities of Newcastle and Queensland has found.
The research, published in Nature, found this natural method provided "substantial carbon and biodiversity benefits".
Forests cover about 31 per cent of Earth's land and operate as the planet's life-support system, safeguarding water, soil, animals and plants, while regulating the climate.
Brooke Williams, of the University of Newcastle, said "the world is coming together to look for solutions to reverse climate change".
"Forest restoration is an important way to do that, but it can be very expensive," said Dr Williams, a conservation scientist.
"What we call active restoration, where we buy seedlings, go out and dig holes and plant trees, can be very expensive, not to mention labour, fencing and maintenance costs.
"Natural regeneration is a way of leveraging what forests do naturally to bring forests back. Forests do come back by themselves."
She said birds, bats and other animals disperse seeds in the forest and "nature does its thing".
"As long as we make room for nature, removing threats close to a forest, then it can come back," she said.
University of Queensland researcher Jiaqi Li said the study pinpointed "holistic hotspots" where natural regeneration provided high carbon and biodiversity benefits and low restoration costs.
These areas were mostly in Indonesia, Madagascar, Philippines, Mexico and Malaysia.
"The carbon benefits stand out most in Neotropical areas like the Amazon basin and in the Indomalayan tropics like Borneo, Sumatra and Papua New Guinea," Ms Li said.
"There are more biodiversity benefits in the Afrotropics including Madagascar."
Dr Williams said it was a global study "focusing on tropical forests in nations with emerging economies or low-to-middle income countries".
Most of the world's tropical forests occur in Africa, South America, Asia, Indonesia and Papua New Guinea.
"Often those are the countries that don't have as many resources as Australia, for example, to restore their forests using active methods," Dr Williams said.
She said the study's purpose was to "help nations save money to reach their ambitious restoration goals".
The concept applied to the Hunter Region "in so many ways".
"We have a lot of land that needs restoring, especially in the post-mining era," she said.
She said deforestation continued to occur in the Hunter.
"There are a lot of examples where we're still cutting down our forests for development and infrastructure projects," she said.
"It doesn't really make sense that we want to restore some areas, but cut down others. For the Hunter, we need forest conservation and restoration that doesn't waste our money."
University of Queensland Associate Professor Matthew Luskin, who co-authored the study, said the research was "a huge leap forward in putting theories about forest restoration into practice".
"I've spent years in the forests around the tropics and seen rampant deforestation first-hand, but I've also seen huge opportunities for regrowth," Dr Luskin said.
"This work will help countries and communities prioritise where and how to invest in restoration, depending on their specific goals and resources to achieve the best outcomes."
