Browsing by Subject "Bestandesklimagradient"

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Vergleichende Betrachtung von Mikroklima, Struktur und aus dem Xylemsaftfluss von Bäumen hochskalierter Transpiration eines tropisch-montanen Regenwaldes und eines Wolkenwaldes in Südost-Ecuador
(2010) Ohlemacher, Christian; Küppers, Manfred
In a tropical montane rain forest 1990 m a.s.l. and a cloud forest 2240 m a.s.l. in the Andes of Southeast Ecuador, tree stand structure (tree height, tree basal area, tree sapwood area, tree crown ground projection area and leaf area index (LAI)) was registered and the sap flow rate of trees, the microclimate (photosynthetically active radiation, temperature, air moisture) inside and above the canopy, and short term stem radius changes were measured. The period of measurement was one year, and synchronous measurements exist from 7 months. To investigate, whether the stand conductance for water differs between the two sites, their stand structure, xylem sap flow and microclimate were compared. Annual stand transpiration was calculated by means of upscaling the xylem sap flow, under inclusion of the site specific microclimate, with the basal area as scaling parameter. Mean radial stem growth was derived from stem radius changes. Radial stem growth is higher in the montane rain forest than in the cloud forest by a factor 3-5. No clear hints were found for different conductivity of trees between the investigated stands. The lower annual stand transpiration of the higher sited cloud forest (238 mm/a^-1) than that of the lower sited montane rain forest (438 mm/a^-1) is caused by a lower stand and foliage density (LAI = 1,6 in the cloud forest vs. LAI = 3,7 in the montane rain forest) and the higher air moisture at the higher sited stand. The crown area-related sap flow rate of single trees is approximately equal at both stands.