Why is Arbor Day March 12?

1979 the National People's Congress Standing Committee (NPCSC) designated March 12 as Arbor Day in China. This day is designated as Arbor Day. One is to commemorate Dr. Sun Yat-sen, who has always attached importance to and advocated afforestation (March 12 is the anniversary of Dr. Sun Yat-sen's death). In addition, on March 12, the temperature and humidity are suitable for plant growth, which is the most suitable time for planting trees.