Science-based measures implemented to protect old, valuable trees

Old and valuable trees are "living fossils" that carry the memories of civilizations. Over the recent years, local authorities across China have been working to ensure that the responsibility of conserving and protecting old and valuable trees is fulfilled, rejuvenate them in a timely manner, and strengthen relevant monitoring and law enforcement, making remarkable progress in protecting and managing these plants.

Photo shows a luxuriant tree with an age of over 1,000 years in Wangjiaba village, Nantong township, southwest China's Chongqing municipality. [People's Daily Online/Cao Yonglong]

In Guanhe village, Jinping township of Chongxin county, Pingliang, northwest China's Gansu province, there stands a gigantic pagoda tree that is 26 meters high. It has an east-west crown spread of 34.2 meters and a north-south one of 37.7 meters. According to estimation, the tree is more than 3,200 years old.

Today, the ancient tree is still vibrant after living thousands of years.

Zhang Jizhen, head of Chongxin county's forestry and grassland bureau, told People's Daily that the county is home to 222 registered old and valuable trees.

The county has taken the protection of old and valuable trees as an important measure to advance ecological progress over the recent years. On one hand, it launched surveys to get the picture of relevant resources in the county; on the other hand, it improved policies and mechanisms to ensure the responsibility of protecting these plants is fulfilled.

Three surveys were conducted to get a knowledge of the trees more than 100 years old in the county by the county's forestry and grassland bureau and township governments, which included field trips and in-situ calculation, and recorded the heights, ages, locations and altitudes of these trees.

Zhang noted that the bureau also made "ID cards" for these plants which reveal their species, serial numbers, genera, classes of protection and managing organizations.

"ID cards" are hung on ancient trees in Hongfeng village, Youxi township, Linhai, east China's Zhejiang province. [People's Daily Online/Jiang Youqing]

Besides, Chongxin county also recruited volunteers for the protection of registered old trees.

In Zhengding county, Shijiazhuang, north China's Hebei province, there is a 600-year-old pagoda tree whose circumference is at least as long as the arm spans of two adults.

"I used to play under the tree when I was little," said Wang Yuhua, an official with Zhengding county's urban management department, who's responsible for protecting the ancient tree. She does physical "checkups" for the tree every day.

"Ancient trees have lived a very long time and their roots are widespread, which makes it difficult to distribute water and nutrients. Thus, these trees are prone to plant diseases," Wang told People's Daily.

Physical "checkups" for trees, just like those for humans, examine the health conditions of trees, including their trunk stability, growth situation, root vitality and soil quality which affects the growth of roots, Wang said.

The checkups not only reveal the health conditions of the trees, but also provide basis for the protection and rejuvenation of them.

According to Wang, detailed plans have been made to ensure these checkups and daily maintenance are well carried out, and once problems are spotted, targeted measures will be implemented.

A checkup is conducted for a 500-year-old ginkgo tree by forestry technicians in Xiangyang, central China's Hubei province. [People's Daily Online/Xie Yong]

The Yellow Crane Tower in Wuchang district, Wuhan, central China's Hubei province, is a famous historical site. Many old and valuable trees are growing around it in the Yellow Crane Tower park.

Shi Hongwen, director of the center for the protection of old and valuable trees in Wuhan, noted that each old tree around the Yellow Crane Tower has its own protection plan, which was formulated based on its species, age, growth situation and the environment it is in.

In the eastern section of the Yellow Crane Tower park, there is a big ginkgo tree encircled by an iron fence as tall as an adult. The fence was erected in 2016 because some citizens often did exercise under the tree, which impacted the growth of the tree's root. After the fence was erected, the park designated another site where citizens can do exercise. This move has put the tree under better protection while addressing the demand of citizens.

In April 2017, a technical code for routine maintenance and rejuvenation engineering of historical trees in urban areas was implemented. According to the code, the maintenance of these trees shall be prioritized, which is the basis for rejuvenation. Feed and bleed, fertilization, pest control, crown cleaning, environment treatment and other technologies should be applied to maintain historical trees, the code said.

Weak and endangered old trees as well as those with potential safety hazards shall be rejuvenated through soil improvement, damage treatment, tree hole repairing and trunk reinforcing technologies.