Aerial photo taken on June 27, 2021 shows the scenery in Saihanba National Forest Park in Chengde, north China's Hebei Province. (Xinhua/Yang Shiyao)

Aerial photo taken on June 27, 2021 shows the scenery in Saihanba National Forest Park in Chengde, north China's Hebei Province. (Xinhua/Yang Shiyao)

Aerial photo taken on June 27, 2021 shows the scenery in Saihanba National Forest Park in Chengde, north China's Hebei Province. (Xinhua/Yang Shiyao)

Aerial photo taken on June 27, 2021 shows the scenery in Saihanba National Forest Park in Chengde, north China's Hebei Province. (Xinhua/Yang Shiyao)