Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Aerial photo taken on March 21, 2022 shows forests in Khao Yai National Park, Thailand. Khao Yai National Park is the first national park in Thailand, with a total area of about 2,168 square kilometers. The annual International Day of Forests is marked on March 21. (Xinhua/Wang Teng)

Editor: Qing Cheng