Impact of the invasion by Bursaphelenchus xylophilus on forest growth and related growth models of Pinus massoniana population

Bursaphelenchus xylophilus (Pine wood nematode, PWN) is a serious pest in pines that changes the original biological and geographical distribution as well as the structure and function of the natural ecosystems. The nematode and associated pine wilt disease have great impact on the stand growth of Masson pine forests in China. The growth rule of individual forest factors after the PWN invasion was analyzed using “the technique of censusing every individual” and “quadrat method”. The results showed that the invasion of PWN in 1996 had significant impact on the diameter growth of the pines, but PWN only seldom affected the height growth of the pines. Based on this, the paper also established the grey forecast and grey-Markov combination models of the growth of Masson pines attacked by PWN. This series of models had a high simulation accuracy and could be applied to predict stand description factors in Masson pine forest, no matter whether it was attacked by PWN or not.