辽东地区次生林林窗生长季初期的光环境特征

Characteristics of light environment in canopy gap of secondary forest at initial stage of growing season in Eastern Liaoning

为了解决次生林合理经营问题,以辽东山区次生林3种典型性林窗为研究对象,对生长季初期林窗光环境特征进行了研究。结果表明:林窗的光量子通量密度(PPFD)日变化均呈单峰型,林窗沿南北轴和东西轴的各点所接收的光强度PPFD值,随林窗面积的增大而增加;林窗面积、位置对直射光指数(DSF)、散射光指数(ISF)、全光指数(GSF)均有显著影响(P<0.05),林窗的全光指数(GSF)与其光量子通量密度(PPFD)存在极显著的正相关关系(P<0.01);林窗面积、位置的不同,使其光环境发生改变,最终影响森林的更新。

Using three typical secondary forest canopy gaps at mountainous regions in Eastem Liaoning as examples, the characteristics of canopy gap light environment at initial stage of growing season were investigated in this study. The results show that the diurnal variation of canopy gap photosynthetic photon flux density （PPFD） presents a single peak, and the PPFD values of light intensity received by each point along east-west axis and south-north axis of canopy gap increase with the increase of canopy gap area. Area and position of canopy gap have a significant effect （P〈0.05） on direct site factor （DSF）, indirect site factor （ISF） and global site factor （GSF）. Global site factor （GSF） and photosynthetic photon flux density （PPFD） of canopy gap have extremely significant positive relationship （P〈0.01）. The different size of canopy gap area and different position of canopy gap will alter the light environment and eventually affect the renewal of forest.