A new study suggests that forests on Earth are changing due to the combined action of human activities and natural phenomena, leading to the loss of the oldest trees and the shorter heights of growth,media reported. Sadly, human-induced climate change is likely to continue as the climate gets hotter.
It is understood that human-induced climate change, timber harvesting and a range of natural phenomena are increasingly putting pressure on forests around the world. A new global study assessed the impact of these devastating effects on global forest dynamics through satellite observations and a review of more than 160 published papers.
As a result, the researchers found that the average height and age of forests on Earth were significantly shorter than a century ago, and that humans were at least partly responsible for this potentially disruptive change.
The paper discusses three conditions that determine the dynamics of healthy forests and how they are destroyed.
The first feature is the introduction, which is a term that refers to the introduction of new saplings that will one day become young trees. The second is growth, which is an indicator of a net increase in biomass, and the third is mortality, which is defined as the loss of plant reproduction and cellular metabolism.
In healthy virgin forests, these characteristics balance each other. Now, however, some aggravating factors are seriously undermining that balance. Rising temperatures, for example, make photosynthesis more difficult for trees and plants. This destroys forests on many levels, as it not only kills trees but also makes them more difficult to regenerate and grow. This is one of the main reasons why people are not seeing forests as high as they used to be.
In addition, prolonged heat can lead to drought, which puts trees under enormous pressure, either by direct death or by making them more vulnerable to insects or diseases.
Since the beginning of the Industrial Revolution, there has been a significant increase in the amount of carbon dioxide in the atmosphere, which may actually help some trees grow and reproduce, but there are some limitations, according to the new study. The benefits of this carbon dioxide fertilization are clearly only observed in relatively young forests, where there is plenty of nutrients and water.
Forest fires are also a serious threat to forests worldwide, as are invasive fungi and parasitic vines. In addition, many of these factors will be exacerbated by the emergence of climate change.
Worse, forests must also respond to threats from direct human action. Rampant timber harvesting and deforestation have led to the felling of many old trees, which has had a significant negative impact on forest ecosystems.
The study data reviewed by the researchers also showed that many of the aggravating factors listed included drought, rising temperatures, deforestation and insect attacks that appeared to affect older trees more than younger trees.
In addition, according to the newly published paper, tree mortality is rising in most areas, while the birth and growth of new trees continue to fluctuate, raising the issue of total loss.
“Over the past 100 years, we have lost many ancient forests, some of which have been replaced by non-forest organisms and partly by young forests,” commented Nate McDowell, a geoscientist at the National Laboratory for the Northwest Pacific in the United States, the study’s lead author. This has implications for biodiversity, climate mitigation and forestry. “
Sadly, as habitat changes will make it more challenging for animals living in denseforests, continued changes in forests on Earth are likely to lead to the loss of biodiversity.
The study has been published in Science.