The research on "strange cars" is expected to solve the problems of efficiency and cost. It is necessary to conduct comprehensive physical examinations on 1.3 million roadside trees

The first true row of street trees in Shanghai appeared in December 1865, planted on the Bund. Over 150 years later, over 1.3 million street trees have become an important component of the urban ecological environment in Shanghai.

But roadside trees can also bring "sweet troubles", as they can have an impact on people's daily lives and even the safety of cities due to factors such as birth, aging, illness, and death. For example, if it grows too fast or too well, it blocks the lighting of road signs, street lights, and residents along the street, or if it is blown down or broken during a typhoon.

In July this year, Typhoon No. 5, Dussuri, caused significant wind and rain impacts on Shanghai, with some roadside trees falling or breaking. Last year's 12th typhoon "Meihua" caused 872 residential trees and 2265 roadside trees to collapse or break.

Fallen trees with clear hollow trunks

The roadside trees are regularly managed and maintained, and preventive measures such as thinning branches and tying reinforcement are also taken before each typhoon. Why does the effect seem to be not significant? A new technology for urban street tree health examination under development is attempting to find an efficient and cost-effective solution.

Recently, a citizen saw a strange car on Jianguo West Road, carrying a bunch of cameras and instruments, slowly moving along the edge of the road, focusing on the trees on both sides of the road.

They didn't know that this strange car was actually a new generation of roadside tree inspection technology being developed in Shanghai.

"In an ideal state, more than 100 roadside trees on the test section can undergo a physical examination in about 5 minutes, performing 8-10 tasks. By using image recognition and other technologies to search for subtle risk points such as insect holes, ant paths, fungi, and mechanical damage on the trees, it is possible to see at a glance whether the tilted state of the roadside trees has reached the level where intervention measures need to be taken." Wang Benyao, the head of the Science and Technology Information Department at the Shanghai Greening Management Guidance Station, explained that when the "electronic eye" passes through a roadside tree, its field of view can cover about three-quarters of the surface of the entire tree from the root to the crown, and only a small area facing away from the road is a "blind spot". ".

The prototype cars running on the streets abroad, while in Shanghai, sedans have been replaced with commercial vehicles with larger capacity

Conceptual diagram of a brand new roadside tree health examination system

To solve the problem of blind spots, the drone carried by the medical examination vehicle can fly to the top of the tree crown and determine whether there are leaf eating pests, powdery mildew, coal pollution and other pests based on the condition of the tree crown branches and leaves.

Jiefang Daily's Shangguan News reporter learned from the Shanghai Greening Management Department that the technology is still in the research and development stage, and it is expected to be put into practical use in some sections of Shanghai by the end of next year.

"At present, in order to strengthen the training of artificial intelligence, it is necessary to first recognize road trees from a pile of street scenes, and then start advanced training to recognize different pest and disease characteristics, which will be more difficult and require a large number of images to enhance the recognition ability of artificial intelligence." Wang Benyao gave an example, where the ant paths left by ants on the trunk of road trees and the sap flowing out after longhorn beetles' boredom are sometimes very similar, and without experience, it may not be possible to recognize them.

Accelerating the research and application of new technologies is related to people's increasing attention to the safety of roadside trees.

"In the past, even the most skilled 'old wizard' only relied on experience and judged problems through vision and touch, making it difficult to detect hidden diseases." Sun An, the head of the Comprehensive Business Department of the Xuhui District Greening Management Center, said that elderly roadside trees and 'big trees' with a diameter at breast height greater than 40 centimeters can no longer be distinguished by visual and appearance inspections after experiencing the baptism of time, typhoon and flood seasons, and changes in municipal infrastructure.

In recent years, the greening department of Xuhui District has adopted new technologies to conduct a comprehensive physical examination of the "big trees" in its jurisdiction. The Picus3 elastic wave tree fault diagnosis instrument and TRU root radar equipment are mainly used to detect the internal conditions of the "chest" and "feet" of roadside trees, and a "one tree, one file" has been established.

Using Picus3 elastic wave tree fault diagnosis instrument to detect problems such as insect infestation in tree trunks

The purple red color shown in the above picture is hollow, the red color is decaying, and the green color is normal wood

Perform CT on tree roots using TRU root radar equipment

Root density detection distribution map

"The results were somewhat shocking. Many roadside trees that we were confident in were either 'osteoporotic' with damaged wood and voids in their trunks, or 'top-heavy' with unevenly distributed root growth and the possibility of tipping over at any time. Sun An stated that these findings are related to urban safety and have prompted everyone to realize the urgency of using new technologies to re evaluate the health and growth status of roadside trees.".

However, comprehensive investigation work requires a large amount of manpower and material resources. The reporter learned that after years of effort, Xuhui District has completed the physical examination of more than 3100 "big trees", accounting for about 60% of the total "big trees" in the region. However, if we refer to the calculation of more than 42000 street trees in the entire Xuhui District, then less than 10% of the total number of street trees that have completed the physical examination.

It is also understood that districts such as Jing'an, Changning, and Hongkou are conducting a thorough investigation into the growth and health status of roadside trees in the area. However, due to limitations in funding, technology, and manpower, they can only selectively select key areas and prioritize the detection of "big trees" and "old trees". This year, the Shanghai greening department will prioritize conducting safety risk assessments on trees in densely populated and heavily trafficked areas, and compile a detailed tree information database based on the collected on-site data.

The Shanghai Greening Maintenance Management Information System has entered a large amount of basic information about roadside trees, such as geographical location, tree species, diameter at breast height, crown width, etc. In the future, the results of physical examinations will also be gradually uploaded, and corresponding management measures will be taken according to the risk level

The development and application of roadside tree examination vehicles may be able to balance efficiency and cost to a certain extent. Wang Benyao stated that although the level of precision in detection is not as good as Picus3 cross-sectional detector and TRU root radar equipment, the roadside tree inspection vehicle can quickly detect surface problems of trees at a low cost, and the related hazard investigation and prevention measures are more targeted.