Based on mathematical modelling, this review article describes the mechanism of expansion in the circumference of vascular cambium due to radial growth leading to increase in the tree-trunk diameter, and emphasizes upon the huge difference in the rate of symplastic growth of cambial initials in two different directions, viz. radial and circumferential. On the basis of anatomical evidence regarding the role of symplastic and intrusive growths, the long-standing hypothesis that the intrusive growth contributes to the increase of cambium circumference has been falsified. It has been shown with the help of mathematical calculations as well as anatomical observations that only symplastic growth of the initial cells (in circumferential direction) is responsible for the expansion of cambial circumference.

这篇综述文章基于数学建模，描述了由于径向生长导致树树干直径增大而导致的血管形成层周长膨胀的机制，并着重强调了两个地方的冈比亚原始声母的共生增长率的巨大差异。不同的方向，即。径向和圆周。根据有关共生性和侵入性生长作用的解剖学证据，长期以来的假说是：侵入性生长有助于形成层形成周长。借助于数学计算和解剖学观察已经表明，仅初始细胞的共生生长（沿周向）才是冈比亚周向扩张的原因。