Evoluzione della Cerchia Legnosa in Castanea Sativa Mill

Summary

The evolution of wood ring in Castanea sativa mill. — The Author has studied the wood ring evolution during one year on two specimens of Castanea sativa Mill. growing respectively the former in a chestnut wood at Masso del Diavolo (ca 1000 m. over sea level), near Vallombrosa, a locality lying outside the normal area of distribution of the species, and the latter at Colle di S. Giusto (ca 500 m. over sea level), near Greve, a locality included in the «horizon» proper of the species. In the former contemporary wood growth of the main stem, branch and sterile shoot has been studied; in the latter wood growth of the stem and the branch only.

The two plants, although growing in ecologically different habitats, show an analogous course in wood ring evolution. Only one ring is differentiated during the year.

The cambium resumes its activity first in the main stem, and subsequentely in the bianch, ending it sooner in the branch than in the stem.

After a first tumultuous phase, cambial activity slows down, while wood elements differentiation goes on in the portion of the ring already formed.

The cambium brings very rapidly to an end its active cycle; at the beginning of Summer the wood ring is complete both in stem and in branch.

In the sterile shoot whose anatomical features are more similar to those of the stem than to the branch ones, the cycle of the wood ring development is parallel to that of the stem.

The beginning of bud-opening both in the branches of the main stem and sterile shoot starts before the awakening of the cambium.

Both cambium awakening and increased wood formation seem to depend on especially favourable temperature conditions, but do not seem to be affected by the amount of precipitations.