Reference
Pilegaard, K., Ibrom, A., Courtney, M.S., Hummelshoj, P. and Jensen, N.O. 2011. Increasing net CO2 uptake by a Danish beech forest during the period from 1996 to 2009. Agricultural and Forest Meteorology 151: 934-946.
What was done
Noting that forests are exposed to a changing environment and that "responses to recent climate change start to become visible if observation periods become long enough," the authors present the results of continuous CO2 flux measurements that they made above a mature Danish beech stand in the "Lille Bogeskov" forest located near Soro on the island of Zealand (55°29'13"N, 11°38'45"E) over the period 1996-2009, describing the long-term changes they observed and relating them to possible causes.
What was learned
Pilegaard et al. report that they observed "significant linear trends of increasing gross ecosystem exchange (GEE: 29 g C/m2/year) and increasing net ecosystem exchange (NEE: 23 g C/m2/year), while the positive trend for ecosystem respiration (RE: 5 g C/m2/year) was not significant." They also state that "the length of the carbon uptake period increased by 1.9 day/year, whereas there was a non significant increase of 0.3 day/year in the leafed period," which means, in their words, that "the leaves stay active longer." Nevertheless, they indicate that "the increase in the carbon uptake period explained only part of the increasing NEE (9 gC/m2/year)." And noting that "the maximum rate of photosynthetic assimilation increased by 15% during the 14-year period," they speculate that the increase in canopy carbon uptake capacity "could be due to a combination of [the] increase in atmospheric CO2, higher summer precipitation, and increased availability of nitrogen."
What it means
Within the context of today's illogical obsession with the ongoing rise in the atmosphere's CO2 concentration, together with the many environmental catastrophes it has been predicted to produce as a result of CO2-induced global warming, the overwhelmingly positive results that were obtained by Pilegaard et al. are most reassuring, especially in light of the fact that the world's climate alarmists claim that the warming experienced over the past quarter-century or so was unprecedented over the last one to two millennia, and their claim that this phenomenon is the greatest threat ever to be faced by the planet. Apparently, the beech trees that the Danish research team studied didn't understand the seriousness of the situation.