This paper is the study on the windbreak effects of trees by wind tunnel tests. The experimental results approximately agree with the measurement values which we reported in the paper part 1. Then we investigate the relation of the space composition and wind characteristics. The results are as follows. (1) □-type, namely the site is completely surrounded by trees, has the best condition for strong wind. But we cann't expect good effects of windbreak in the site area over 4H X 6H. Here, H is height of Fukugi-tree. Mean height of Fukugi is about 8.6m, then there is realy no site area more than 1700m^2 in Okinawa. (2) It is the best for windbreak that the location of the house is at the position of 3H apart from the trees.
