Chandigarh: Tree health survey completed in 45 sectors

The Chandigarh Municipality (MC) in association with the Dehradun-based Forest Research Institute (FRI) has completed tree counting and health assessment in the sectoral areas of the city and will now start surveys in erstwhile villages.

So far, the FRI team has surveyed as many as 134,000 trees, covering over 45 sectors in Chandigarh, and also conducted ultrasound examination of over 300 trees. In response, the MC has already removed nine trees on the institute’s recommendation, which were found to be “hollow” during the ultrasound examination.

Since September last year, the government institute FRI has been carrying out an inventory of trees standing in the MC jurisdiction, assessing their health and the condition of their hollows, at a price ₹23.33 lakhs.

“A team from FRI Dehradun visited the city and conducted surveys from time to time, which included physical examination as well as ultrasonographic examination of vulnerable trees to be recommended for removal to avoid danger during rains and strong winds. The team hopes to cover the entire area by the end of the year and submit a report on the health of trees, dead and dry trees and trees to be removed based on the ultrasonographic examination conducted by the institute,” MC Commissioner Anindita Mitra said, adding that nine trees, which were found hollow during the survey, have already been cut down.

After visiting each site, an enumeration of trees is carried out, and observations of insect pests such as woodpeckers, defoliators, bark beetles and tree end infestations are made, then samples are taken, insects are identified and recommendations for their control are issued. The institute then examines individual trees for signs and symptoms of diseases, after sampling, laboratory isolation and identification of pathogens.

The institute also determines the ultrasonic velocity along multiple transverse directions of the tree trunk to examine the hollowness of the tree trunk. Based on the ultrasonic velocity, the central hollowness of the tree trunk is estimated. For this purpose, only potentially dangerous trees are tested, at an additional cost ₹400 per tree.

Last census

In 2017, the municipal body’s horticulture department conducted the first ever tree census in the city, but it did not have a scientific methodology to count trees and assess their condition. A total of 1.65 lakh trees were recorded in the census, of which 262 were considered dangerous and 1,029 were dead or dry.

Chandigarh has a total forest area of ​​22.88 sq km and an estimated tree cover of 15 sq km, which is 33% of the geographical area of ​​the union territory. With age, the vigour of trees may reduce, making them susceptible to pathogens and insect pests. Several diseases like heart rot and root rot make trees susceptible to wind gusts. Trees may be uprooted or the trunk may split in a depression, becoming a threat to life and property. Therefore, physiological study of trees as well as soil analysis are required to identify the biotic and abiotic factors contributing to the deterioration of tree health and factors of various problems.

On July 8, 2022, a heritage peepal tree fell at Carmel Convent School, Sector 9, Chandigarh, killing a 16-year-old girl and injuring 19 others. There were also numerous incidents of damage to vehicles and other property due to felling of trees.