Researchers warned that if the drought affecting California continues, it could have irreversible effects on almost 60 million trees.

Based on their findings, the water content in the canopies of millions of trees in the state has already dropped severely.

According to Mongabay, the drought in California began in 2011. Even though rains brought on by the El Nino season have offered some form of relief on the landscape, researchers say these are not enough to put the trees out of harm's way.

In fact, the U.S. Forest Service revealed that a total of 12 million trees have already died during the course of California's four-year drought.

Using spectroscopy tools with laser-guided imaging features, researchers from the Carnegie Institute of Science carried out a large-scale study on the effects of the drought on the environment of California.

They were able to observe the conditions of a large area containing about 888 million trees. Based on their observations, the researchers noted that the trees in this area have suffered serious canopy water loss. Specifically, they noted that about 58 million trees have lost at least 30 percent of water content.

"Our maps reveal much wider, much larger-scale impacts on our forest than the dead trees would tell in themselves," researcher Greg Asner said according to the San Francisco Chronicle. "We found that there was measurable drought stress even in areas that are known to be more humid."

The research team explained that aside from their environmental benefits, trees play an important role in the economic and cultural aspects of California and that losing them would have serious repercussions on the state.

"California relies on its forests for water provisioning and carbon storage, as well as timber products, tourism and recreation, so they are tremendously important ecologically, economically and culturally," Asner noted in a press statement.

"The drought put the forests in tremendous peril, a situation that may cause long-term changes in ecosystems that could impact animal habitats and biodiversity," he added.

Despite their findings, the researchers are still confident that the data they have collected will be able to help other organizations and authorities take the proper actions to save the trees.

By identifying the exact areas that are hard-stricken by the ongoing drought, authorities will be able to know which regions are most vulnerable and which have the greatest wildfire risks, CBS News reported.

The findings of the researchers were detailed in a study published on December 28 in the journal Proceedings of the National Academy of Sciences.