Phenological variations of three urban forest trees grown in north and upper Egypt

Abstract EN

Patterns of leaf-flushing, leaf-completion, defoliation, flowering-on, flowering-off, pod (fruiting)-on, pod maturation and pod opening of trees were studied to detect the phenological variations of Albizia lebbeck, Cassia javanica, and Delonix regia trees in both Alexandria, as North of Egypt, and Aswan, as Upper Egypt, for three consecutive annual cycles (from first week of March 2009 to December 2011).

At both cities, the trees of three genera began to flush leaves during spring season (April- June), reached a completion phase before the summer season.

The results indicate that, high temperature resulted in leaves completion beginning 3-5 weeks earlier and defoliation delayed 13- 25 weeks later, as noticed in Aswan for the three genera.

Additionally, max.

and min.

temperature and day length were well correlated with leaves flushing of both Albizia lebbeck and Delonix regia in Alexandria as well as, for Cassia javanica in Aswan.

On the other hand, max.

and min.

temperature, and day length were also significantly correlated with flowering of both Albizia lebbeck and Cassia javanica in Aswan whereas, correlation between max.

temperature and min.

temperature were existed only for Cassia javanica with leaves flushing in Alexandria.

Generally, relative humidity did not affect the observed phenophases of the three genera in both cities during the three years