Restore 100 Hectares of the Miyagi Coastal Forest

The beginning of June, Dendrolimus spectabilis, which only consumes pine, had abnormally occurred, and we were busy dealing with the issue. There were lots of confirms in occuring of another caterpillar, some caterpillars had poison. Our staff and volunteers who related to work were stung by poisonous hair, and they received damage such as; an itching sensation in their arms and neck. Although Dendrolimus spectabilis doesn’t have personal damage, they ordinally consume pine leaves so if we keep letting loose them, pine’s leaves would disappear in an instant. It’s obvious that the result of decline of photosynthetic rate, stopping tree height stretch, the trunk not becoming thick, and decreasing root’s growth. In order to grow strong coastal forest, it’s really necessary to exterminate above caterpillars.

By getting the cooperation of 182 volunteers in total, we executed caterpillar extermination by spraying in 1.75ha (equivalent to 5,775 Japanese black pines) of the most damaging area in our project on three days from 13 to 15 in June. We estimated that we could exterminate more than 30,000 caterpillars. Next week, the pesticide was sprayed by power sprayer by the cooperation of all people from the organization of the Natori-shi shore forest reproduction (Natori-shi kaiganrin saisei no kai) who are in charge of making plants. Contrary to this fact, We could check that caterpillars have spread over a span of approximately 23 ha north of 100 ha in after survey, hence we decided to execute aerial chemical spraying by helicopter on June 26th.

On that day, 2 aerial work platforms to carry operators who control 2 helicopters, 2 tracks which load equipment and chemicals and 9 expert staff were gathered at 4am. The reason why we start work in the early morning, if it is a morning when the wind is light the risk of the chemical scattering out of the forest would be decreased. 30L chemicals were sprayed per 1 ha. Different from drones, the helicopter’s chemical carrying capacity is a lot and can work efficiently,therefore spraying to approximately 32ha forests and withdrawal of all equipment finished at 8am.

Toshimichi Yoshida who is in charge of this project mentioned that “Though I thought that the time will come that aerial chemical spraying by helicopter would be demand to suppress the damage from Dendrolimus spectabilis one of these days, I didn’t expect that we’ll be flying helicopters to exterminate caterpillars.”, and he appreciate that “Thank to all of you who support us, we were able to decide quickly.” We’ll patrol 100ha’s pine forest regularly, not to miss small abnormalities, and deal with it immediately if there are some factors to avoid pine’s improvement and we would like to grow strong coastal forest. Thank you for your continued support.