Relationship between seasonal cambial activity, development of xylem and phenology in Azadirachta indica growing in different forests of Gujarat State

Abstract

Seasonal cycle of cambial activity was compared among the trees of Azadirachta indica growing in Moist Deciduous (MDF), Dry Deciduous (DDF) and Scrub land Forest (SF) of Gujarat State. Radial growth occurred in two growth flushes in MDF and DDF. Cambial cell divisions in MDF started in February and June resulting maximal radial growth in August-September when the rains were heavy and ceased in January and May during the drier part of the year. In DDF the first flush of growth commenced in January with maximal xylem development in April and ceased in May. The second flush of cambial activity began in June with the arrival of rains, reached peak in October and ceased in December. Cambium was active throughout the year in SF and attained its peak activity thrice i.e. in February, July and October. With complete maturation of leaves in November, the cell divisions were rather slow in MDF and SF whereas no divisions were encountered in DDF. Cambial rays exhibited large intercellular spaces during drier months in all the three forests. Seasonal behavior of vascular cambium was discussed in relation to phenology and local climatic conditions.