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Titolo:
EFFECTS OF OVERSTORY AND UNDERSTORY VEGETATION ON THE UNDERSTORY LIGHT ENVIRONMENT IN MIXED BOREAL FORESTS
Autore:
MESSIER C; PARENT S; BERGERON Y;
Indirizzi:
UNIV QUEBEC,GRP RECH ECOL FORESTIERE,CP 8888 SUCC CTR VILLE MONTREAL PQ H3C 3P8 CANADA
Titolo Testata:
Journal of vegetation science
fascicolo: 4, volume: 9, anno: 1998,
pagine: 511 - 520
SICI:
1100-9233(1998)9:4<511:EOOAUV>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTON FLUX-DENSITY; FAR-RED RATIO; RAIN-FOREST; TROPICAL FORESTS; EFFICIENT METHOD; QUERCUS-SERRATA; CARBON GAIN; GROWTH; TEMPERATE; CANOPIES;
Keywords:
ABIES BALSAMEA; BETULA PAPYRIFERA; FOREST UNDERSTORY; LIGHT ENVIRONMENT; POPULUS TREMULOIDES; SUCCESSION; SUNFLECK; THUJA OCCIDENTALIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
52
Recensione:
Indirizzi per estratti:
Citazione:
C. Messier et al., "EFFECTS OF OVERSTORY AND UNDERSTORY VEGETATION ON THE UNDERSTORY LIGHT ENVIRONMENT IN MIXED BOREAL FORESTS", Journal of vegetation science, 9(4), 1998, pp. 511-520

Abstract

The percentage of above-canopy Photosynthetic Photon Flux Density (%PPFD) was measured at 0, 50 and 100 cm above the forest floor and abovethe main understory vegetation in stands of (1) pure Betula papyrifera (White birch), (2) pure Populus tremuloides (Trembling aspen), (3) mixed broad-leaf-conifer, (4) shade-tolerant conifer and (5) pure Pinusbanksiana (Jack pine) occurring on both clay and till soil types. %PPFD was measured instantaneously under overcast sky conditions (nine locations within each of 29 stands) and continuously for a full day under clear sky conditions (five locations within each of eight stands). The percent age cover of the understory layer was estimated at the samelocations as light measurements. Mean %PPFD varied from 2 % at the forest floor under Populus forests to 15 % above the understory vegetation cover under Betula forests. Percent PPFD above the understory vegetation cover was significantly higher under shade intolerant tree species such as Populus, Betula and Pinus than under shade tolerant conifers. No significant differences were found in %PPFD above the understoryvegetation cover under similar tree species between clay and till soil types. The coefficient of variation in %PPFD measured in the nine locations within each stand was significantly lower under deciduous dominated forests (mean of 19 %) than under coniferous dominated forests (mean of 40 %). %PPFD measured at the forest floor was positively correlated with %PPFD measured above the understory vegetation and negatively correlated with cumulative total percent cover of the understory vegetation (R-2 = 0.852). The proportion of sunflecks above 250 and 500 mu mol m(-2) s(-1) was much lower and %PPFD in shade much higher underPopulus and Betula forests than under the other forests. Differences in the mean, variability and nature of the light environment found among forest and soil types are discussed in relation to their possible influences on tree succession.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 19:28:06