Fire-resistance of Six Tree Species to Fire Probed by Chlorophyll Fluorescence

Forest fires happen frequently in South China, of which Yunnan, Guangdong, Guangxi, and Hunan provinces are observed above one thousand forest fires on average annually. Although the forest management and fire fighting forces have been improved and strengthened, the fire disaster did not decrease. Fire-resistant vegetation plays an important role in the prevention of forest fire, which can slow down or prevent fire effectively. Thus, researches on the fire-resistant vegetation are the basis for establishing forest belts to reduce fire damage.

Photosynthesis is the most important physico-chemical process of plant. Photosystem II (PSII) is thought to be the primary and sensitive site of inhibition in photosynthesis apparatus induced by a wide range of environmental stresses. There are numerous published studies of the combustibility of plant and the effect of fire on the growth, sprout and survival of plants, but researches about damage of fire on photosynthesis of plant are very few. However, this information is essential to the selection of tree species and the development of appropriate management strategies for fire-prevention.

The objective of this research was to evaluate the influence of fire on the photosynthesis of Myrica rubra, Camellia japonica, Rhododendron siderophyllum, Gardenia jasminoides Ellis, Osmanthus fragrans Lour. and Nerium oleander, six important fire-resistant tree species in Yunnan Province, China, which was probed by chlorophyll fluorescence in vivo. The results showed that C. japonica, O. fragrans and N. oleander were the species most tolerant to fire treatment, whereas R. siderophyllum, G. jasminoides and M. rubra were the tree species less tolerant. Fire treatment inhibited the activity of photosynthesis of R. siderophyllum, G. jasminoides and M. rubra, whereas the influence of fire on C. japonica, O. fragrans and N. oleander was mainly through increasing the energy dissipation to decrease the fire damage on photosynthesis apparatus. The order of fire resistance of six tree species to fire was put forward as follows: C. japonica, N. oleander, O. fragrans, M. rubra, G. jasminoides and R. siderophyllum.

The result has been published on Journal of Food, Agriculture & Environment, 2012, 10(2): 1329-1333. The paper can be downloaded from http://www.world-food.net/scientficjournal/2012/issue2/pdf/environment/249.pdf.