It sounds like a great idea to fight climate change — but a new study has thrown a bucket of cold water on the notion of planting trees to stop global warming.

The study, published this past week in the journal Science, shows that forests are increasingly made up of dark green conifers in Europe has actually increased the pace of global warming, showing that not all trees are good for battling climate change, according to a Christian Science Monitor report.

European forests have grown 10 percent since 1750, but summer temperatures on the continent have increased 0.12 degrees Celsius, or 0.2 degrees Fahrenheit. Scientists think that planting pines and spruces are the reason why, because their dark colors actually trap the sun’s heat. The continent needs more broad-leafed trees that are a lighter coal, such as oak and birch trees, so as to reflect sunlight back into space.

The problem is that conifers are heavily used in the economy, and therefore are preferred over other types of trees.

Scientists think about 6 percent of the global warming observed so far is due to an increase in temperature caused by these trees. And scientists are seeing similar afforestation in china, the United States, and Russia, so the problem could actually get worse.

“Two and a half centuries of forest management in Europe have not cooled the climate,” researchers wrote in the study. “The political imperative to mitigate climate change through afforestation and forest management therefore risks failure, unless it is recognized that not all forestry contributes to climate change mitigation.”