Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Sun Kaimeng)

Photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Sun Kaimeng)

Photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/Tao Ming)

Aerial photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/He yu)

People enjoy the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province, May 30, 2019. (Xinhua/Wang Wei)

Photo taken on May 30, 2019 shows the scenery of Wulongdong National Forest Park in Lueyang County, northwest China's Shaanxi Province. (Xinhua/He Yu)