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Effects of light availability and tree size on the architecture of assimilative surface in the canopy of Picea abies: variation in shoot structure

Title data

Niinemets, Ülo ; Kull, Olevi:
Effects of light availability and tree size on the architecture of assimilative surface in the canopy of Picea abies: variation in shoot structure.
In: Tree Physiology. Vol. 15 (1995) Issue 12 . - pp. 791-798.
ISSN 1758-4469
DOI: https://doi.org/10.1093/treephys/15.12.791

Abstract in another language

Dependence of shoot morphology on relative irradiance (diffuse site factor, a(d)) and total tree height (TTH) was studied in a natural canopy of Picea abies (L.) Karat. Surface area of foliar elements was characterized by total needle area (TLA, all-sided needle surface), projected needle area (PLA, area of detached needles laid flat on a horizontal surface), and vertical and horizontal silhouette shoot areas (SSA(0) and SSA(90), defined as shadows cast by shoots with fixed horizontal inclinations of 0 degrees and rotation angles of 0 degrees and 90 degrees, respectively). With increasing irradiance and tree size, packing of needles (needle number per unit shoot length, L(s)) and packing of TLA (TLA/L(s)) increased, but packing of SSA(0) (SSA(0)/L(s)) was invariant. Accordingly, the SSA(0) to TLA ratio (STAR(0)) decreased, signifying that the proportion of TLA exposed to direct solar radiation declined, and thus the cost of SSA(0) in terms of TLA increased with increasing a(d) and TTH. Factors causing costlier SSA(0) at high irradiances and in tall trees included increases in needle packing, changes in needle morphology (increases in needle dry weight per TLA and decreases in TLA/PLA), and changes in needle position and angle of needle inclination. The weight of the shoot axis (M(a)) was used as an estimate of biomass costs for mechanical support of the needles and water supply to the needles. Foliage-area-based needle-support costs (NSCa), defined as M(a) per unit foliage surface (TLA, PLA or SSA(0)) increased with a(d) and were not related to TTH, whereas foliage-weight-based needle-support costs (M(a)/M(D)) decreased with increasing TTH and were independent of a(d).

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER7067
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology > Chair Plant Ecology
Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Biology
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 500 Science
Date Deposited: 11 Sep 2015 06:35
Last Modified: 11 Sep 2015 06:35
URI: https://eref.uni-bayreuth.de/id/eprint/19410