Article Reforestation or Genetic Disturbance: A Case Study of Pinus thunbergii in the Iki-no-Matsubara Coastal Forest (Japan) Aziz Akbar Mukasyaf 1,* , Koji Matsunaga 2 , Miho Tamura 1, Taiichi Iki 3, Atsushi Watanabe 1 and Masakazu G. Iwaizumi 4,* 1 Department of Forest Environmental Science, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395, Japan;
[email protected] (M.T.);
[email protected] (A.W.) 2 Kyushu Regional Breeding Office, Forest Tree Breeding Center, Forestry and Forest Product Research Institute, 2320-5 Suya, Koshi, Kumamoto 861-1102, Japan;
[email protected] 3 Tohoku Regional Breeding Office, Forest Tree Breeding Center, Forestry and Forest Product Research Institute, 95 Osaki, Takizawa, Iwate 020-0621, Japan;
[email protected] 4 Kansai Regional Breeding Office, Forest Tree Breeding Center, Forestry and Forest Product Research Institute, 1043 Uetsukinaka, Shoo, Katsuta, Okayama 709-4335, Japan * Correspondence:
[email protected] (A.A.M.);
[email protected] (M.G.I.) Abstract: In the twentieth century, a substantial decline in Pinus thunbergii populations in Japan occurred due to the outbreak of pine wood nematode (PWN), Burshaphelencus xylophilus. A PWN- P. thunbergii resistant trees-breeding project was developed in the 1980s to provide reforestation materials to minimalize the pest damage within the population. Since climate change can also contribute to PWN outbreaks, an intensive reforestation plan instated without much consideration can impact on the genetic diversity of P. thunbergii populations. The usage and deployment of PWN-P. thunbergii resistant trees to a given site without genetic management can lead to a genetic disturbance.