Climate change makes trees greener and younger

The height of forests around the world has decreased significantly, and their age has also increased significantly over the past 50 years.

That's the result of a study published in the journal Science on Friday. What does this result mean? The forest's ability to remove carbon from the atmosphere is no longer the same, and the living conditions it provides for many forest-based animals to take refuge also diminish. More worrying, it's all just the beginning, the situation could get even worse!

The team evaluated more than 160 previous studies, analyzed satellite images, and modeled to investigate how the forests have changed from between 1900 to 2015. They found that It turns out that over a period of more than 115 years, the world has lost up to 14% of its forest because of logging. Of these, 30% are perennial forests, which are home to trees older than 140 years and often are tall forests with very high levels of biodiversity.

The study did not address other environmental impacts on trees, such as an increase in carbon dioxide levels due to rising carbon emissions, and more severe climate problems, which were more frequent, such as pest infestation, wildfires, and drought. Nate McDowell, a scientist at the Pacific Northwest National Laboratory and the lead author of the study, said that means the above 30% figure is " a very conservative estimate ".

In North America and Europe, where more detailed data is available, researchers found that tree mortality doubled over the period, and older plants accounted for a large portion of that number. Their findings show that the world is losing a lot of older trees. Because of the lack of data, the researchers were unable to give an accurate estimate of how much the height of the forests had decreased.

Elsewhere, the decline in the number of trees is occurring at different frequencies and for various reasons. While wildfires are a major cause in Australia and Mongo, in California, widespread wildfires and pest infestation have seriously reduced forest area. And the tropical rainforests in the Amazon are increasingly facing land reclamation . There are rare exceptions: for example, tree mortality in parts of the Pacific Northwest is declining.

But while the variation in forest conditions varies from region to region, its impact is noticeable on a global scale. 80% of shore plants and animals live in forests. Old forests have a high level of biodiversity and are home to many endangered species. They also store large amounts of carbon dioxide.

" The old forests to this day are the largest onshore carbon storage, " McDowell said. " Small trees cannot store much carbon, while larger trees can ."

The world is losing a lot of old trees.

In the context of the climate crisis becoming more and more serious, this trend will continue. Earth temperatures are rising, and climate problems such as forest fires, droughts, and insect outbreaks are also becoming more frequent and serious.

All of this creates a vicious cycle. When older plants die, they not only stop collecting carbon, but also release all the carbon they once collected back into the atmosphere. Young trees that grow in place of them are more likely to become victims of wildfires, thereby releasing more carbon into the atmosphere. In short, global warming kills trees, and a decline in the number of trees contributes to global warming.

There are still a few ways to minimize these losses.

" Communities living around forests have made encouraging efforts, such as periodically burning and reducing tree density in forests in the West, where the ecosystem is frequently exposed to wildfires, and now they are no longer at risk of that "- McDowell said. " Creating fires in a sensible manner can minimize the events that cause great loss and disturbance to the ecosystem. Those are the solutions that we are applying, but they are not. be applied on the scale needed. Scaling up will be a global challenge . "

Perhaps the biggest challenge to reducing the loss of forests is how to reduce carbon emissions. This can help protect forests, and when we can protect forests, we can control the global carbon cycle. If we do not make efforts to conserve forests, not only the elderly trees will be affected - all living things on Earth will suffer the same fate. Scientists are currently doing more research to identify all the effects, and they're obviously not very good at all!