Trees are losing their leaves earlier because of climate change

Previous models had suggested that fall would be delayed as the season got warmer over the coming century.

(CNN)Trees will start to shed their leaves earlier as the planet warms, a new study has suggested, contradicting previous assumptions that warming temperatures are delaying the onset of fall.

Every year, in a process known as senescence, the leaves of deciduous trees turn yellow, orange and red as they suspend growth and extract nutrients from foliage, before falling from the tree ahead of winter. Leaf senescence also marks the end of the period during which plants absorb carbon dioxide through photosynthesis.
Global warming has resulted in longer growing seasons -- spring leaves are emerging in European trees about two weeks earlier, compared with 100 years ago, researchers said.
    "Previous models assumed that because autumns will get warmer and warmer over the coming century, autumn will get delayed -- growing seasons will overall get longer, and autumn will get delayed by two to three weeks," ecosystem ecologist Constantin Zohner said.
      However, Zohner and a team of researchers have said their findings reverse this prediction.
      "We actually predict by the end of the century, leaves might even fall off three to six days earlier," Zohner, a corresponding author on the paper published Friday in the journal Science, added.
      Using a combination of field observations, laboratory tests and modeling, experts studied data that tracked six European deciduous tree species -- European horse chestnut, silver birch, European beech, European larch, English oak and rowan -- over the last six decades.