Climate change is making trees bigger, but weaker
http://www.sciencemag.org/news/2018/08/climate-change-making-trees-bigger-weaker
Source: By Lakshmi Supriya, Science Magazine.
Excerpt: As global temperatures rise, trees around the world are experiencing longer growing seasons, sometimes as much as three extra weeks a year. All that time helps trees grow faster. But a study of the forests of Central Europe suggests the higher temperatures—combined with pollution from auto exhaust and farms—are making wood weaker, resulting in trees that break more easily and lumber that is less durable. ...For the past 100 years, trees have been experiencing growth spurts in temperate regions from Maryland to Finland, to Central Europe, where the growth rate of beech and spruce has sped up nearly 77% since 1870. Assuming wood is just as dense today, those gains would mean more timber for building, burning, and storing carbon captured from the atmosphere. ...But Hans Pretzsch, a forest scientist at the Technical University of Munich in Germany, and his colleagues wondered whether the quality of the wood has changed. ...They found that in all four species, wood density has decreased by 8% to 12%, they report online in Forest Ecology and Management. ...As the density of the samples dropped, so did their carbon content, by about 50%. ...But Pekka Kauppi, an environmental scientist at the University of Helsinki, says another factor more than makes up for the climate impact: the faster-growing forests. “The negative change of wood density is by far less important than the positive change” of a global turnaround from shrinking to expanding forests, he says....
Source: By Lakshmi Supriya, Science Magazine.
Excerpt: As global temperatures rise, trees around the world are experiencing longer growing seasons, sometimes as much as three extra weeks a year. All that time helps trees grow faster. But a study of the forests of Central Europe suggests the higher temperatures—combined with pollution from auto exhaust and farms—are making wood weaker, resulting in trees that break more easily and lumber that is less durable. ...For the past 100 years, trees have been experiencing growth spurts in temperate regions from Maryland to Finland, to Central Europe, where the growth rate of beech and spruce has sped up nearly 77% since 1870. Assuming wood is just as dense today, those gains would mean more timber for building, burning, and storing carbon captured from the atmosphere. ...But Hans Pretzsch, a forest scientist at the Technical University of Munich in Germany, and his colleagues wondered whether the quality of the wood has changed. ...They found that in all four species, wood density has decreased by 8% to 12%, they report online in Forest Ecology and Management. ...As the density of the samples dropped, so did their carbon content, by about 50%. ...But Pekka Kauppi, an environmental scientist at the University of Helsinki, says another factor more than makes up for the climate impact: the faster-growing forests. “The negative change of wood density is by far less important than the positive change” of a global turnaround from shrinking to expanding forests, he says....