Chinese fir ( Cunninghamia lanceolata ( Lamb. ) Hook. ) forest stands were greatly damaged by the huge snowfall in 2008, which resulted in resinosis in Chinese fir trees. Wood slices with resinosis were observed and analyzed. Results show that resinosis is related with the abnormal structure caused by self-protection response of the compressed cambium. Density of phloem fiber in the trunk from outer to inner gradually increased. Several concentric circles formed in the phloem after the snow disaster. Xylem ray bended in the cambium, which caused a bottleneck effect in the conducting tissue and stimulated the formation of abnormal tissue-traumatic resin. Collapse happened in the inner wall of xylem tracheid. Axial parenchyma decreased gradually from the pith. Because of the snow compressing, horizontal radial tissue crimpled, nutrient transport was restrained, and abundant traumatic resin occurred. Resinosis occurred naturally under the pressure when resin accumulation surpassed the holding capacity of canal.%通过对流脂材解剖性质研究发现,雪压杉木林分树干大量流脂与形成层受压产生应激性反应及形成异常结构有关.杉木树干韧皮纤维分布密度自外向内逐渐增大,雪压后形成的韧皮部环绕形成层呈若干个同心圆,木质部射线在形成层处发生转折,导致输导组织产生瓶颈效应,刺激了非正常组织即韧皮部创伤树脂道的形成;木质部管胞内壁产生皱缩现象;轴向薄壁组织自髓心向外,明显呈逐渐减少之趋势.雪压导致行横向输导功能的射线组织发生皱褶,营养物质横向输导受阻,产生大量创伤树脂道;当创伤树脂道内树脂的富集超过其储存能力,在分泌压力作用下就会自然发生溢脂现象.
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