[Changes of reflectance spectra of pine needles in different stage after being infected by pine wood nematode].

In the present study, seedlings of Pinus Thunbergii and Pinus Massoniana were planted and used for reflectance spectrum measurement. In different stage after being infected by pine wood nematode, reflectance spectra were measured by ASD spectrometer and the features of spectral parameters and the change of chlorophyll were analyzed. The results showed that (1) Disease could be estimated in the early stage according to the curve of mid-infrared reflectance; (2) Dynamic parameters such as the position of red edge, green peak height, reflectance of red band, slope of red edge and reflectance of water-stressed wave band were consistent with the disease features of two pine species after being infected by pine wood nematode; (3) To both of two pine species, content of chlorophyll tended to reduce with the development of disease and obvious linear relationship was observed between chlorophyll content and spectral parameters. There results might be able to provide some theoretical basis for the application of remote sensing technology in monitoring of pine wood disease. In addition, it might be also used as theoretical support for the controlling measures in different stage after being infected by pine wood nematode.

[Biological and ecological bases of using insect as a bio-indicator to asses forest health].

Insect is an important component of forest biodiversity, which is closely related with plant in the main community of forest ecosystem. Intimidation of forest pest and variation of insect diversity is of importance for assessing forest ecosystem health. Insect diversity can be used for rapidly assessing forest ecosystem health. For example, indicator insects have been used to evaluate toxicity levels, abundance of species, levels of biodiversity, target insect status, and endemism levels for forest ecosystem. With a focus on the important interference factors influencing forest environmental health, this paper clarified the biological and ecological basis for insects to be used as a bio-indicator to monitor and assess forest health. We also discussed the fluctuation of insect populations, especially that of the population of the rare species under the influence of habitat fragmentation, and the density and distribution of the insect population under the influence of air pollution, drought, increased CO2 concentration. Meanwhile, the existing problems to use insects as a bio-indicator to monitor and assess forest environmental health were analyzed.