PLOTS UNDER EXPERIMENT.

In 1912 three plots were selected for experiment. Each contained about

fifty trees varying in age from seedlings to eighteen years old. This

year two new plots were added to the three of 1912. Some tree surgery

work was done, and the trees sprayed with lime-sulphur.

Final report of the Pennsylvania Chestnut Tree Blight Commission · 第 67 / 145 题