The ugly effects of global warming have started becoming visible in the botanic life of the western United States and Canada; that’s what a new study by U.S. and Canadian researchers articulates. 

The study has revealed that the rising temperature is resulting in draught, and consequently, the trees in the western United States and Canada are dying more than twice faster than they did just 30 years ago.

Researchers studied that tree census data gathered in 1955 and in later years, and found that the death rate of trees increased in 87 percent of the 76 forest areas studied. They also found that in some areas the die-off rate doubled in as little as 17 years; in others, it doubled after 29 years.

According to the researchers, it’s working like a chain reaction – the rising temperature and drought reduce the ability of the trees to absorb carbon dioxide, which absorbs heat and contributes to global warming. It is weakening and thinning forests, and thinner and weaker forests are becoming more vulnerable to wildfires.

The researchers say the warmer temperatures may be encouraging pine beetles and other organisms that attack trees, and that, along with the stress of prolonged droughts, may be accelerating death rates in trees. 

One of the lead researchers, Phillip van Mantgem of the U.S. Geological Survey, said, "Average temperature in the West rose by more than 1 degree F (half a degree C) over the last few decades.”

“Summers are getting longer. Trees are under more drought stress,” said Nathan L. Stephenson, of the United States Geological Survey, another lead researcher of the study.

In the study, which will appear in Friday’s issue of the journal Science, researchers concluded that “trees of various species, ages and sizes are dying faster at every elevation”.