Volunteers in Pune map riverside trees with smartphones to defend the city's urban forest

On weekend mornings in Pune, western India, volunteers with smartphones and measuring tapes walk the city's riverbanks, recording trees one by one, Mongabay reported on 30 October. The citizen science project, run by the grassroots group Pune River Revival on the iNaturalist platform, is building a record of the city's riverside trees.

Measuring, photographing, uploading

Volunteers estimate each tree's height and girth, photograph it and upload the record to iNaturalist under the Mutha River biodiversity project. The group began systematic tree mapping in 2024, said volunteer Raghunandan Patil. “Our main focus from tree mapping is to protect the riparian zones in the city,” he said.

Ananya Gandhi, 24, has mapped the riparian zones for two years. On the Saturday Mongabay joined, seven volunteers were working in Madhavrao Scindia Garden on the bank of the Mula River, where a college student, Vivek Lanjewar, identified gum from a moringa tree.

Evidence when trees are threatened

Patil says the mapping serves as evidence for advocacy. When 529 trees were felled on Ganeshkhind Road, volunteers mapped more than 500 trees within a month. The group has also focused on the Ram-Mula Devrai, a sacred grove where the Ram and Mula rivers meet, which official reports say holds about 1,000 heritage trees. After public protests, the city was to revise riverfront development plans affecting the grove, which now faces a much lower risk of heavy development, according to Mongabay.

The city's planned Pune Riverfront Development Project along the Mula-Mutha rivers is estimated at about 4,727 crore rupees, roughly $500 million. Global Forest Watch reports that Pune lost 40 hectares of natural forest in 2025.

Citizen-generated tree data “is welcome as supplementary information during the tree census process.” — Ashok D. Ghorpade, Pune Municipal Corporation

Can volunteer data be trusted?

The city's chief garden superintendent, Ashok Ghorpade, said the data can supplement official records if it is validated. A 2017 study comparing volunteer and expert tree surveys in four cities in the US and Sweden found 90% agreement on site type, land use, dieback and genus, and correct species for 84.8% of trees within the right genus. More citizen science stories are collected under citizen science.