Of these, 5,462 trees have already been cut.
Revenue Minister Chandrakant Patil said the National Highways Authority of India's (NHAI) proposed widening of the Mumbai-Goa highway (NH-66) will affect 10,509 trees on the Panvel-Indapur stretch that is 84-km long.
"Of the affected trees, 5,462 have already been cut. The state has also obtained necessary environmental clearances for the project. As per the agreement, the number of trees to be planted will be three time more than the number of trees to be chopped," he said.
The minister was replying to a query raised by MLAs Sunil Shinde and Jayant Patil in the Lower House.
The land requirement for the four-lane road conversion on the Panvel-Indapur stretch is 217 hectares, of which legal hearing for 203 hectares has been completed, according to the written response.
The road widening is taking place in several phases.
The government's proposal for constructing a connecting road and a tunnel on the Indapur-Zarap stretch of the highway was struck down by the Centre, he said.
The stretch between Indapur (in Pune district) and Zarap in Konkan region is 366-km long.
The government has invited e-tenders for planting some 1,600 trees on the 91-km stretch between Aravali and Waked, the response stated.