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| Titel |
Biogeochemical factors contributing to enhanced carbon storage following afforestation of a semi-arid shrubland |
| VerfasserIn |
J. M. Grünzweig, I. Gelfand, Y. Fried, D. Yakir |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 4, no. 5 ; Nr. 4, no. 5 (2007-10-24), S.891-904 |
| Datensatznummer |
250001968
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| Publikation (Nr.) |
 copernicus.org/bg-4-891-2007.pdf |
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| Zusammenfassung |
| Ecosystems in dry regions are generally low in productivity and carbon (C)
storage. We report, however, large increases in C sequestration following
afforestation of a semi-arid shrubland with Pinus halepensis trees. Using C and nitrogen (N)
inventories, based in part on site-specific allometric equations, we
measured an increase in the standing ecosystem C stock from 2380 g C m−2
in the shrubland to 5840 g C m−2 in the forest after 35 years,
with no significant change in N stocks. Carbon sequestration following
afforestation was associated with increased N use efficiency as reflected
by an overall increase in C/N ratio from 7.6 in the shrubland to 16.6 in the
forest. The C accumulation rate in the forest was particularly high for soil
organic C (SOC; increase of 1760 g C m−2 or 50 g C m−2 yr−1),
which was associated with the following factors: 1) Analysis of a small
13C signal within this pure C3 system combined with size
fractionation of soil organic matter indicated a significant addition of new
SOC derived from forest vegetation (68% of total forest SOC) and a
considerable portion of the old original shrubland SOC (53%) still
remaining in the forest. 2) A large part of both new and old SOC appeared to
be protected from decomposition as about 60% of SOC under both land-use
types were in mineral-associated fractions. 3) A short-term decomposition
study indicated decreased decomposition of lower-quality litter and SOC in
the forest, based on reduced decay rates of up to 90% for forest compared
to shrubland litter. 4) Forest soil included a significant component of live
and dead roots (12% of total SOC). Our results suggest a role for
increased N use efficiency, enhanced SOC protection and reduced
decomposition rates in the large C sequestration potential following
afforestation in semi-arid regions. These results are particularly relevant
in light of persistent predictions of drying trends in the Mediterranean and
other regions. |
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