Hyperspectral characteristics of typical subtopical trees at different levels of simulated acid rain

Abstract

In this study, we evaluateed the spectral response characteristics of 6 typical tree seedlings in subtropical areas under acid rain in different simulative levels. The experiment shows that there are conspicuous differences between the coniferous and broadleaf in terms of their sensitivities to the acid rain. 3 conifers, i. e. Pinus massoniana, Cunninghamia lanceolata and Torreya grandis are evidently more sensitive to the acid rain than Machilus pauhoi, Cinnamomum camphora and Myrica rubra, 3 kinds of broad鄄leaved trees. For conifer, the chlorophyll content of Pinus massoniana and Cunninghamia lanceolata was greatly higher than that of Torreya grandis. For the species of broad鄄leaved trees, however, there was no significant difference among the Machilus pauhoi, Cinnamomum camphora and Myrica rubra. Since Pinus massoniana, Cinnamomum camphora and Torreya grandis cannot stand the high level of acid rain, their chlorophyll content at first increaseed and later declineed, which was contrary to that of Cunninghamia lanceolata. While Myrica rubra could withstand long鄄term acid rain of high level, its chlorophyll content under pH2. 5 was higher than that under pH5. 6. As for the Machilus pauhoi, there was no evident law in the changes of chlorophyll content of Machilus pauhoi during the 4 experimental phases. What忆 s more, the red鄄edged spectral reflectance positions of the testing plants were substantially