Photosynthesis And Spectral Reflectance Of3Dominant Trees Along Forest Vertical Structure In Broad-leaved Korean Pine Forest

The broad-leaved Korean Pine forest in Changbai Mountain is the top forest community in China. In this paper, we measured photosynthesis capacity and spectral reflectance of3main tree species in this forest along with a vertical gradiant. The relationship among leaf pigment content, leaf spectral reflectance characteristic, and leaf photosynthesis in researched plants were investigated. To evaluate the carbon assimilation capacity of the broad-leaved Korean Pine forest from remote sensing observation,we also discuss the remote estimation of photosynthesis in different species during growing season.Leaf anatomy and physiology were also estimated based on leaf spectral reflectance. Besides, we monitored the photosynthesis capacities of these tree species through different seasons. The results showed:[1]The relationship between multiple spectral reflectance indices and leaf pigment content is complex. Some indices, which was provided to be strongly related to leaf Ch1content, showed a high corelations with leaf Ch1content in all three tree species. Especially SR(Simple Ratio)and NDVI(Normalized Difference Vegetation Index) based on reflectance750nm and705nm, had significantly positive correlation of Ch1content. Caroteinoid index was not closely related to leaf Caroteinoid concentration of Pinus koraiensis and Tilia amurensis. Three reflectance indices we used in this study were related to Car/Chl ratio, though this corelations were not stable between different species.[2]Leaf spectral reflectance of T. amurensis and Quercus. mongolica were investigated during late development stage. The results indicated that leaf senescence process appear to be earlier in Q. mongolica. Also, photosynthetic apparatus in P. koraiensis must be able to withstand periods of low temperature or/and water deficit and still maintain its photosynthetic capacity during autumn season. However, both leaf content and photosynthesis capacities in these two species desceased at the end of this season.[3]Seasonal changes of leaf pigment content and photosynthesis in T. amurensis and Q. mongolica were measured along tree height. Results showed a significant seasonal variations. It was proved that Q. mongolica with lower height have a successful growth in understory of forest, where the radiation is not so much intensive. This research suggested that leaf photosynthesis in saplings of Q. mongolica decrease much more significantly at the middle of vegetation process, compared to mature plants. On the other hand, T. amurensis was sensitive to environment light condition. The changes of PRI and Chl content were fluctuated violently at the middle growing stage, because of the increased solar radiation.[4] The photochemical reflectance index(PRI), derived from foliar reflectance at531nm and570nm, had been promoted for the evaluation of seasonal changes in three examined tree species. A high correlation between PRI and photosynthetic capacity had been confirmed in T. amurensis, Q. mongolica and P. koraiensis. However, careful attention must be paid when using this index as a indicator of seasonal viariation of photosynthetic capacity in different tree species.