Aerial photo taken on Aug. 22, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province. (Photos: Xinhua)

Aerial photo taken on Aug. 22, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 23, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 22, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 22, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 22, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 23, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.

Aerial photo taken on Aug. 23, 2021 shows the scenery of Saihanba forest farm in north China's Hebei Province.