Scientists Track How Plants Are Growing Back in China's Big Coal Mining Region

Scientists in China have been studying how plants grow and recover in one of the country's largest coal mining regions, called the Shendong mining area. They used satellite images taken over nearly 40 years — from 1986 to 2024 — to track changes in plant life there. Their goal was to understand how coal mining harms plants and how well those plants can come back after mining stops or slows down. The study used a powerful online tool called Google Earth Engine, or GEE, to handle huge amounts of data quickly.

Coal is a rock that is burned to make electricity and heat. China produces more coal than any other country in the world — about 52 out of every 100 tons of coal mined globally comes from China. Coal is very important to China's energy supply, making up about 58% of all the electricity the country generates. But digging for coal causes serious problems for the environment, including damage to plants, soil, and land.

When land is mined for coal, plants are often destroyed. Giant machines dig up the earth, leaving behind pits and piles of waste rock. The ground can sink in some areas, a process called subsidence. All of these changes make it very hard for plants to survive. Scientists want to know how bad the damage is and whether plants can grow back after mining activities end.

To measure plant health from space, scientists use something called the Normalized Difference Vegetation Index, or NDVI. This is a number calculated from satellite images that tells us how green and healthy the plants in an area are. A higher NDVI number means more and healthier plants, while a lower number means fewer or unhealthy plants. NDVI is one of the most popular tools scientists use to study vegetation in mining areas.

The research team found that in the Shendong mining area, some parts of the land — about 3.92% — showed steady plant loss over time. These areas were mainly the open-pit mines, where the land is dug up from the surface. However, other parts of the mining area actually showed improvement. After people planted trees and took other steps to restore the land, plants began to grow back in many places.

The scientists used a method called univariate linear regression to find out whether plant cover was going up or down over time. They also used a technique called empirical orthogonal function decomposition, which helped them find the main patterns in how plants changed across different areas. Together, these methods gave scientists a much clearer picture than older methods could provide.

One big challenge in studying mining areas is that the land changes very quickly and in complicated ways. Mining activity can damage plants in a matter of months, but recovery can take many years. That is why having data that covers a long period of time — nearly four decades — was so important. Most earlier studies only looked at short time periods, which made it hard to see the full story of how plants recover.

Google Earth Engine made it much easier to study such a large area over such a long time. GEE is a computer platform that stores huge amounts of satellite images and lets scientists run calculations on them without needing to download all the data to their own computers. This saves a lot of time and effort. Because of tools like GEE, scientists can now study the environment in ways that were not possible before.

The study also looked at what caused plants to grow back or continue to decline. Human activities like mining and grazing were found to hurt plant growth. But government programs focused on ecological restoration — like planting trees and protecting land — had a positive effect. This shows that when people take action to repair the environment, it can make a real difference.

The researchers hope their findings will help government officials and environmental planners make better decisions about how to manage and restore land in mining areas. Knowing where plants are recovering and where they are still struggling can help direct resources to the right places. The scientists also hope their methods can be used to study other mining regions around the world. Protecting plant life in mining areas is an important step toward keeping ecosystems healthy for the future.