A long history, old buildings and rich folk culture are often the measure of a region’s civilization. However, old trees are also valued as an important indicator.

Known as the “the root of Shanghai,” Songjiang is the cradle of the city’s culture and civilization, on which Shanghai developed from a small fishing village to today’s metropolis. How deep are the roots? The district’s ancient trees can tell.

Trees over 100 years old are “old trees,” and those of rare breeds or special historic significance are “valued trees,” according to Shanghai’s greening and forestry bureau. Trees from 80 to 100 years old, regarded as “follow-up old trees,” are also under protection.

“Beautiful architecture can be built and rebuilt, but old trees cannot once they die,” said Zhu Chunchu, former director of the local greening and forestry bureau.

Shanghai boasts a total of 1,613 old and valued trees, and Songjiang has 220, topping the list, of which 40 trees are over 300 years old. The district has 210 follow-up trees.

There are over 39 varieties, such as the “living fossil” ginkgo, camphor, beech and yellow sandalwood, growing in Xinqiao and Yexie towns as well as Sheshan Hill.

Of those, 11 trees are over 600 years old while tree ginkgo trees have reached 1,000 years. On the eastern side of Phoenix Hill, stand two ancient ginkgo trees, one male and another female, who have defied time together over the course of their 10-century-long life. They have been nicknamed the “ginkgo couple” by locals. Around mid-November every year since the Tang Dynasty (AD 618-907), the couple shed their leaves and turn the eastern hillside into a sea of golden yellow.

Songjiang is also home to Shanghai’s largest old tree group — 100 century-old trees of camphor, beech, boxwood and magnolia living shoulder by shoulder on Sheshan Hill.

Other old tree groups are scattered around the district’s historical landmarks, such as Zuibai Pond Park with its wisteria, peony, osmanthus and wintersweet shrubs, Songjiang Mosque flanked by old pine trees, and Hansan Hall built in 1925 featuring a group of ginkgo and jujube trees in its courtyard.

Old trees survived storms, diseases, logging sprees, political movements and civil wars over centuries. Most of the old trees living today in Songjiang today are in temples, which escaped misfortune.

A 1,000-year-old ginkgo was found in Futian Temple, while the original site of a 400-year-old camphor was in Bei’an Temple, which was later renovated to today’s medical cotton factory. Fangta Park, which features old tree groups, was once the location for Songjiang’s Chenghuang God Temple.

However, many old trees were either destroyed in storms, fires or from diseases and insect attack.

The old ginkgo tree in the northwest of Jixiang Village was struck by lightning and caught fire 10 years ago, leaving a charred trunk. The 700-year-old pine tree in Shihudang Town with a girth of 11.6 meters and a crown of 60 meters was also hit by lightning in 1937 and the fire was on for three days and nights, hollowing out the tree trunk.

Human damage was another reason, though often with the best intentions. As old trees were always respected by people as a living God, locals would burn joss sticks, light up candles and hold worship ceremonies under the trees, which could easily catch fire.

The old ginkgo in Yue Temple and the pine tree in Shihudang Town were all harmed by burning incense, left with black stains and damage to their trunks.

Diseases and insect pests were also tree killers. The group of 52 ginkgo in Central Park in New Songjiang City was almost destroyed by termites. Part of the soil in the park, transported from the old buildings to be demolished, was found to have wood-eating white ants. Luckily they were discovered in time and the trees were treated promptly.

In order to better protect old trees, Songjiang has an inspection team whose members’ main duty is to observe the trees’ growth, check the heath condition and surrounding environment changes.

With the rapid urban development, human’s activities and construction projects are grabbing the living space for old trees. Songjiang regulates that property developer of any project around an old tree must hand in a tree-protection plan before the construction starts, and the inspector is required to follow the project from the very beginning to the end.

In the expansion project of Songjiang Hospital, a 100-year-old jujube tree was in the way. The relocation plan was drafted several times until it got the permit from the local greening and forestry bureau. It cost about 260,000 yuan (US$41,000) to move the tree to the nearby Hansan Hall 100 meters away. New fences were set up and today it thrives and receives special care.

At the same time, new techniques are adopted to rescue the old trees, such as using radar to detect root system and spraying microbial fermentation bacteria broth.

Lightning rods are placed on the old trees over 300 years old in the towns of Yexie, Maogang and Sheshan Hill.

Each one of the 430 old trees is kept with a file, which records detailed information of the tree’s age, height, girth, root, crown, growth condition, pest control, photos taken in different seasons, surrounding soil, buildings and any ongoing construction nearby.

“It is rare to have so many old trees in a metropolis, thanks to the long history of Songjiang as well as the local efforts of protection for years from not only the government level and experts but also ordinary citizens,” Zhu said.

Last year, a businessman offered 500,000 yuan to buy three old trees (one beech and two hackberry trees) from farmer Gu Zhaohua in Datie Village, Chedun Town. The trees were planted by Gu’s forefathers and have grown for more than 80 years. The farmer refused and applied to the local greening and forestry bureau. Thus the three trees got listed and their files were created for better protection.

“Old trees are a great treasure because a place where old trees grow always has history, legends and culture. To protect them is to protect our own civilizations,” Zhu said.