Differential responsiveness in stem height and diameter growth of two Ficus tree species in the Three Gorges reservoir region of China as affected by branch removal

In the Three Gorges reservoir region of China, Ficus microcarpa L. and Ficus virens Ait. var. sublanceolata (Miq.) Corner (Moraceae) are widely used in greening and ecological restoration following construction, including roads, railways, towns, etc. Branch cuttings are used for cultivating saplings of these trees. We conducted a 4 year experiment that included four branch-removal intensities to evaluate the influence of branch removal on stem height and diameter growth of these Ficus spp. It was found that branch removal did not affect the stem height growth of either F. microcarpa or F. virens, but decreased the growth of their stem basal diameters. The reduction in growth of stem basal diameter was intensified with branch removal. As expected, branch removal decreased the tapering of whole tree stems, but this effect was mainly due to the alteration of the shape of the bare stem part, and the shape of the stem part within the intact upper crown was not affected by the treatment. The data clearly showed that stem height growth was less sensitive than stem diameter growth to branch removal, and that the response of stem diameter growth to branch removal differed between bare and intact stem parts.