长白落叶松人工林下草本植物对光环境变化的响应

对长白落叶松(Larix olgensis Henry)人工林进行带状皆伐和不同强度择伐,利用冠层分析仪研究冠下草本植物多样性、生物量、高生长和盖度对光环境变化的响应.结果表明:林下草本植物的多样性、生物量、高生长和盖度都随着光照强度的增大而增加,但不同主伐方式草本植物响应的光照强度区间和策略不同.在皆伐林带内,物种多样性与总辐射强度间没有明显相关性;在择伐林下,物种多样性与总辐射强度显著线性相关,光照越强,多样性越高.对比不同主伐方式可以发现,即使总辐射指数相同,皆伐带内也比择伐林冠下具有相对较高的草本植物多样性、生物量及盖度,说明带状皆伐更有利于草本植物生长和种群数量增加.同时发现,当总辐射指数i0.15时,不论哪种主伐方式草本植物的生物量、高生长及盖度均处于较低水平;而当i0.15时,草本植物的高度和盖度进入加速生长期;当i0.25时生物量开始进入加速生长期.研究结论可为林下生物多样性研究,确定合理的主伐方式及择伐强度提供参考依据.

Response of Herbaceous Diversity and Biomass to Luminous Environment Changes under Larix olgensis Plantations

The clear-cutting in strips and selective cutting at different intensities were carried out. The response of herbaceous diversity,biomass and high growth to luminous environment changes under the larix olgensis canopy was studied by means of canopy analyzer. The results showed that herbaceous diversity,biomass,high growth and coverage under canopy increased with the increase of total radiation index. However,different systems of cutting, the illumination range of the response of herbaceous plants is slightly different. There is no clear correlation between species diversity and total radiation intensity in clear cuts. In selective cutting, there is a significant linear correlation between species diversity and total radiation intensity. The stronger the light,the higher the herb diversity. Comparing different methods of cutting,it can be found that even with the same total radiation index value,the clear cutting zone has a relatively higher diversity,biomass,and coverage of herbaceous plants than under the canopy,indicating that clear cutting is more beneficial to herbs growth and population growth. At the same time,when the total radiation index i<0. 15,the biomass,high growth and coverage of herbaceous plants in the main cutting mode are at low level;When i>0. 15,the height and coverage of the herb entered the accelerated growth period;When i>0. 25,the biomass began to enter the accelerated growth phase. The conclusions of this study can provide reference for the study of understory biodiversity,determine a reasonable method of cutting and the intensity of selective cutting.