[MCN] In 40 periods of drought, big trees first to die

[Lance Olsen]

"Š the serious meaning in a concept lies in the 
difference it will make to someone if it is true."
William James (1842 -1910)
Pragmatism. Meridian Books, 1955
=========================

Nature Plants Published online:28 September 2015
doi:10.1038/nplants.2015.139

Larger trees suffer most during drought in forests worldwide
Amy C. Bennett, Nathan G. McDowell, Craig D. 
Allen & Kristina J. Anderson-Teixeira

Abstract (bold emphasis added for readers' quick convenience)
http://www.nature.com/articles/nplants2015139

The frequency of severe droughts is increasing in 
many regions around the world as a result of 
climate change (1, 2, 3). Droughts alter the 
structure and function of forests (4,5). Site- 
and region-specific studies suggest that large 
trees, which play keystone roles in forests (6) 
and can be disproportionately important to 
ecosystem carbon storage (7) and hydrology (8), 
exhibit greater sensitivity to drought than small 
trees (4,5,9,10). Here, we synthesize data on 
tree growth and mortality collected during 40 
drought events in forests worldwide to see 
whether this size-dependent sensitivity to 
drought holds more widely. We find that droughts 
consistently had a more detrimental impact on the 
growth and mortality rates of larger trees. 
Moreover, drought-related mortality increased 
with tree size in 65% of the droughts examined, 
especially when community-wide mortality was high 
or when bark beetles were present. The more 
pronounced drought sensitivity of larger trees 
could be underpinned by greater inherent 
vulnerability to hydraulic stress (11, 12, 13, 
14), the higher radiation and evaporative demand 
experienced by exposed crowns (4,15), and the 
tendency for bark beetles to preferentially 
attack larger trees (16). We suggest that future 
droughts will have a more detrimental impact on 
the growth and mortality of larger trees, 
potentially exacerbating feedbacks to climate 
change.


-- 
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are the very people who would consider themselves 
its most ardent advocates : the bosses of 
companies, the owners of companies, and the 
politicians who tirelessly insist that they are 
'pro-business'."

"Many of the corporate scandals that America, 
especially, has endured in recent years reflect 
outright criminality. A lawful order knows what 
to do with criminals, and pro-business 
politicians are in truth militantly 
anti-capitalist if they flinch from cracking down 
on bosses' crimes."

"Š widespread and quite outrageous abuse, by 
capitalists, of capitalism Š The danger exists 
everywhere in the world, but it matters most in 
the United States."

The Economist, Special 160th Anniversary Issue, A 
Survey of Capitalism and Democracy, June 26-July 
4, 2003


















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