On Sunday, July 3rd, 15 people participated in the 3rd Sophia Forest Citizens' Lecture "Enjoying the Summer Forest" at Sophia Forest in Karuizawa Town, Nagano Prefecture. Even in Karuizawa, the weather and the heat wave which had continued until the day before eased on the day, to enable participants to enjoy pleasant forest trail and plaza walk. In the dark green summer forest, the number and variety of flowers seems to have decreased compared to spring, but participants could find some tiny and sober blooming flowers on the forest floor, and cheers raised. In addition, various kinds of stink bugs were found, and they were surprised to find stink bugs were so beautiful. In addition, there was an explanation of the eclipse marks by a large tree of Onigurumi and a squirrel, and an explanation of the germination of acorn fruits. In sum, participants could fully enjoy and obtain some new findings of the summer forest.