Walker, A.P., De Kauwe, M.G.,
Medlyn, B.E., Zaehle, S., Iversen, C.M.,
Asao, S., Guenet, B., Harper, A.,
Hickler, T., Hungate, B.A., Jain, A.K.,
Luo, Y., Lu, X., Lu, M., Luus, K.,
Megonigal, J.P., Oren, R., Ryan, E.,
Shu, S., Talhelm, A., Wang, Y.-P.,
Warren, J.M., Werner, C., Xia, J.,
Yang, B., Zak, D.R. and Norby, R.J.
2019
"Decadal biomass increment
in early secondary succession
woody ecosystems is increased
by CO2 enrichment."
Nature Communications 10:
454, DOI: 10.1038/s41467-019-08348-1.
NOTE:
Walker et al. (2019),
say biomass responses
are the greatest uncertainty
in model projections
of terrestrial
carbon sink responses
to increasing CO2.
It's uncertain if CO2-induced
growth enhancements observed
in short-term experiments
are maintained over decades.
SUMMARY:
Biomass increase
from CO2 enrichment
(to 550-700 ppm)
in the four early
secondary-succession
temperate ecosystems,
was a positive
29 ± 11.7%
over the course of
about one decade,
while the NPP change
( net primary production )
was a positive
22.9 ± 6.1%
in the same period.
The temporal change
in plant biomass
was found to be related
to the cumulative change
in NPP (cNPP),
such that for every
kg C m-2 increase
in cNPP, the change
in vegetative biomass
increased by
0.55 ± 0.17 kg C m-2.
Positive outcomes
should be realized
in decades to come
as the air’s CO2 content
continues to rise
in response to the use
of fossil fuel energy.
DETAILS:
The 27-member
research team
of Walker et al.
analyzed the biomass
and net primary production
(NPP) responses
from four long-term
(one decade)
ecosystem CO2-enrichment
experiments conducted
in the United States.
All of the site locations
were dominated by woody
plant species and each study
had measured major
components of NPP.