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| THE ROLE OF DEEP ROOTS IN THE HYDROLOGICAL AND CARBON CYCLES OF AMAZONIAN FORESTS AND PASTURES |
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| Author(s): NEPSTAD DC, DECARVALHO CR, DAVIDSON EA, JIPP PH, LEFEBVRE PA, NEGREIROS GH, DASILVA ED, STONE TA, TRUMBORE SE, VIEIRA S |
| Source: NATURE Volume: 372 Issue: 6507 Pages: 666-669 Published: DEC 15 1994 |
| Times Cited: 421 References: 32 |
| Abstract: DEFORESTATIONS and logging transform more forest in eastern and southern Amazonia than in any other region of the world(1-3). This forest alteration affects regional hydrology(4-11) and the global carbon cycle(12-14), but current analyses of these effects neglect an important deep-soil link between the water and carbon cycles. Using rainfall data, satellite imagery and field studies, we estimate here that half of the closed forests of Brazilian Amazonia depend on deep root systems to maintain green canopies during the dry season. Evergreen forests in northeastern Para state maintain evapotranspiration during five-month dry periods by absorbing water from the soil to depths of more than 8 m. In contrast, although the degraded pastures of this region also contain deep-rooted woody plants, most pasture plants substantially reduce their leaf canopy in response to seasonal drought, thus reducing dry-season evapotranspiration and increasing potential subsurface runoff relative to the forests they replace. Deep roots that extract water also provide carbon to the soil. The forest soil below Im depth contains more carbon than does above-ground biomass, and as much as 15% of this deep-soil carbon turns over on annual or decadal timescales. Thus, forest alteration that affects depth distributions of carbon inputs from roots mag also affect net carbon storage in the soil. |
| Document Type: Article |
| Language: English |
| Reprint Address: NEPSTAD, DC (reprint author), WOODS HOLE RES CTR, WOODS HOLE, MA 02543 USA |
Addresses:
1. EMBRAPA, CPATU, BR-66001 BELEM, PARA BRAZIL
2. UNIV CALIF IRVINE, DEPT EARTH SYST SCI, IRVINE, CA 92717 USA |
| Publisher: MACMILLAN MAGAZINES LTD, PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW |
| Subject Category: Multidisciplinary Sciences |
| IDS Number: PX307 |
| ISSN: 0028-0836 |
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| | | | | | | | | Record from Web of Science® | | | | | | | | | |