Just planting trees damages ecosystem: experts
POOR reforestation efforts will cause forests to degrade and rare native species to become extinct, experts have warned while stressing that the goal when reforesting denuded land should be to preserve biodiversity.
Many campaigns to restore forests end up damaging forest ecosystems instead of saving the environment, experts say, because people plant invasive alien species – trees that can grow fast and tolerate harsh environments better.
Asst Prof Ferry Slik, a lecturer at University of Brunei Darussalam, emphasised that the true value in preserving forests was to protect their rich biodiversity, as all species have their responsibility in a forest ecosystem and humans were yet to discover how useful all of these exotic species were.
“The rainforest in Southeast Asia has an extremely high density of biodiversity. There are more than 25,000 plant species in this region compared to around 100 plant species in the entire European continent and many plant species here are rare and very localised,” Slik, a leading biologist said.
“Therefore, to help a forest recover, we should do it very carefully, so as not to clear out native plants when replanting new trees, not introducing alien species, and more preferably we should preserve the genetic signature of the area.”
Sutthathorn Chairuangsri, the education director of the Forest Restoration Research Unit at Chiang Mai University, said that in Thailand there were many examples of failed reforestation efforts, which had resulted in degrading forests.
“Many people in Thailand still do not have proper knowledge about our own forest ecosystem. So, we usually adopt reforest campaigns from elsewhere, which may not suit our unique ecosystem and bring in alien species that can be harmful to the biodiversity and overall ecosystem in the long run,” Sutthathorn said.
Slik said reforestation was really about returning biodiversity suited to the local environment. So, in some cases, the picture of “real” reforestation may differ from most people’s sense of what reforestation is.
“In most people’s view, reforestation is just planting trees to create a lush vegetation area. But for scientists like me reforestation must return the rich biodiversity to an area,” he said.
The country’s reforestation leader, Forestry Department director-general Chonlatid Suraswadi, said the department had improved its methods of reforestation to suit local environments by using academic knowledge.
“The main area for restoring forests is mostly in the mountains, and we usually use native species seen in mountainous regions to replant the forest, and for efforts to preserve biodiversity. We also plant a variety of more than 10 species per rai of land,” Chonlatid said.
“We consider the survival of the newly planted forest as first priority. So, we have a strict monitoring process after the trees have been planted. We build firebreaks to prevent wildfires, replant if trees perish, and seek to use the kinds of trees that have a high survival rate, to ensure that the new forest would survive.”
However, Sutthathorn warned that selecting trees that grow fast and can tolerate a harsh environment could be harmful to forest ecosystems, because these species were usually invasive and tended to take over areas, to the extent that other species were unable to grow. In the end, the forest would have just a handful of dominant species.
Replanting forests has been popular among both the private and public sector as an act of good will – to increase the amount of forest, preserving a healthy environment, and tackling global warming.