Clever Trees Won't be Fooled by a Tricky Climate

Ecologists have long worried that as climate change continues to affect the seasons, trees might "leaf out" too early, only to be struck by late-season frosts. Some trees, however, are too clever for such a simple trick, somehow knowing to wait it out despite spurts of warm weather.

Unusual and premature temperature hikes have become more and more common across the globe as our climate continues to change. Whether human-driven, or simply a natural process, the change in seasonal temperature activity patterns is undeniable. While for many people, random spurts of spring-like weather in the dead of winter may seem like a blessing, botanists are less thrilled, worried that the unusual warm weather will prompt plants to flower and turn their leaves out earlier than they should.

In some cases, this actually occurs, with foolhardy plants then feeling the wrath of an unfinished winter. However, many of the most vulnerable of trees are simply too clever to be tricked by a few days of sunshine.

According to a study recently published in the journal Ecology Letters, a team of researchers at the Ludwig Munich Botanical Garden were able to observe tens-of-thousands of plants from diverse climate zones, measuring their bloom or leaf out timing.

"Such a comprehensive phenological study has never been undertaken before," head researcher Susanne Renner said in a statement, adding that nearly 500 different species of woody plants in particular were observed.

According to the researchers, common botanical knowledge dictates that temperature and day-length determine when a plant will choose to turn its leaves out, making them vulnerable to the elements in order to collect sunlight.

The researchers quickly found that many flowering plants can be easily tricked by temperature alone, so they bloom too early, and perish once chilly weather returns.

However, many woody plants that thrive in warm climates, such as the beech tree from Central Europe, appear to be almost entirely dictated by the length of a day.

"The beech in Central Europe is a relic of the warmer temperatures that prevailed during the Tertiary Period; leaf emergence requires 13 hours of daylight, regardless of whether the spring was warm or cool and moist," Renner said.

While this insensitivity to temperature may appear at first like a crutch, causing the plant to potentially miss out on the start of the spring season, it has now proved an invaluable adaptation, protecting it from "tricky" changing climates.