树木向阳一侧比相对一侧生长速度快，存在向阳性特征。由于向阳性的原因，不同纬度地区树木年轮中心位置偏移性不同，北半球偏移现象可识别纬度至少达北回归线（N23.6°）附近。地史中保存的硅化木年轮形态也能反映它们的古纬度位置。开展重点地区硅化木年轮形态调查，可以为古纬度提供信息。我国古地磁学者通过研究，得出中生代以来华北板块方位发生过大幅度旋转的结论。硅化木年轮的向阳性测量可验证板块运动。通过对原生直立硅化木树干（近根部）年轮向阳性测量，比对相同地区现生树木年轮的向阳性数据，推断华北板块的运动情况。实现多学科之间的互补和验证。

Trees on the side directly exposed to sunlight generally grow faster than the opposing side, a phenomenon termed plant phototropism. The center of the growth rings (pith) moves obviously because of the phototropism, which could be found to the Tropic of Cancer (N23.6°) in the Northern Hemisphere. The situation is the same in the petrified wood. The invisgations which will be done on the growth rings in petrified wood will give more information about palaeolatitude. Palaeomagnetists have revealed that the North China Plate has significantly rotated since the Mesozoic. It is possible that the rotation of the North China Plate be supported by the investigation of phototropism of the in situ preserved fossil wood especially near the roots. Compared the phototropism of the petrified wood with the modern normal growth stumps in plain area, this observation supports the conclusion of previous palaeomagnetic studies that the North China Plate has rotated. The complementary and validation of the multidisciplinary has been done.