L. Gratani et I. Foti, ESTIMATING FOREST STRUCTURE AND SHADE TOLERANCE OF THE SPECIES IN A MIXED DECIDUOUS BROAD-LEAVED FOREST IN ABRUZZO, ITALY, Annales botanici Fennici, 35(2), 1998, pp. 75-83
To explain the coexistence of plant species in a mixed deciduous broad
-leaved forest in Abruzzo, Italy, a number of leaf traits were analyze
d, and the shade tolerance was investigated. Bud break started at the
end of April and the rapid leaf growth during the first stages was att
ested by the highest relative growth rates. The leaf area index (LAI)
increased from 0.7 at the beginning of the leaf growth to 2.6 at full
lamina expansion. Most of the species of the dominated layer were shad
e-tolerant and most of the species of the dominant and co-dominant lay
ers were shade-intolerant. There was a fairly well defined specific le
af area (SLA) range between the shade-tolerant (271.1 cm2 g(-1)) and s
hade-intolerant species (159.2 cm2 g(-1)). The SLA, the chlorophyll co
ntent (Chl) and the leaf water content showed the same trend from the
top to the bottom of the forest canopy. The chlorophyll a/b ratio rang
ed from 2.78 (dominant + co-dominant layers) to 2.95 (dominated layer)
. Laburnum anagyroides Medicus, one of the most shade-tolerant species
(305.1 cm(2) g(-1) SLA), showed the highest total chlorophyll content
(2.69 mg g-L) and Quercus cerris L., one of the most shade-intolerant
(148.2 cm2 g(-1) SLA), the lowest (0.70 mg g(-1)).