Photo taken on April 2, 2018 shows the spring scenery of Medog County in southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 1, 2018 shows the spring scenery of a waterfall in Medog County in southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 1, 2018 shows the spring scenery of Medog County in southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 2, 2018 shows the erythrina flowers in Medog County, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 1, 2018 shows a stream in Medog County, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 1, 2018 shows the alsophila spinulosa, a rare tree species, in Medog County, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 2, 2018 shows the spring scenery of Medog County in southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)