Streets and flyovers silently invaded into the city’s green cover over the past seven years, intensifying the prickly heat.

Around 8,500 trees were brought down across the city since 2007 for various infrastructure and construction projects, including widening of roads.

The rampant tree-felling over the years, environmentalists claimed, contributed to the rise in average summer temperature and uncomfortable index.

“The green cover absorbs a lot of solar heat because plants have an auto-cooling mechanism. The non-green areas, on the other hand, reflect heat, leading to heating up of the atmosphere. Today, Patna is filled with such non-green areas. For instance, none of the trees that stood along the Gardiner Road around 10 years ago are visible today,” said Ashok Ghosh, member, State Level Expert Appraisal Committee — a technical panel of the state environment impact assessment authority.

In order to check the loss of green cover, Dipak Kumar Singh, the environment and forests secretary, has issued an order stating that the approval from the Patna divisional forest officer (DFO) alone was no more enough to bring down trees.

The sanction would be issued only after principal chief conservator of forest (PCCF) reviews the necessity of felling the trees.

“The decision has been taken to prevent unnecessary felling of trees. It has been observed that different (government) agencies exert pressure on the Patna DFO quite often for allowing them to fell trees for some project or the other. The PCCF has now been introduced in the procedure to raise the decision-making level in giving sanction for tree-felling. No approval on tree-felling in Patna would now be given without the written consent of the PCCF,” said Dipak.

Patna DFO Gopal Singh said the permission for felling a few hundred trees had recently being given for some ambitious projects, including Bihar Museum (popular as international museum), extension building of Patna High Court, International Convention Centre and Jagdeopath-Sheikhpura Mor flyover.

Dipak has prohibited felling of the standing trees under these projects. The PCCF would now review the necessity of bringing down them before arriving at a final decision on the same.

“Considering the limited scope of planting trees in the Patna urban area, all possible steps should be taken to preserve the existing trees. The permission to cut such trees should be given only when it is absolutely necessary,” said Dipak.

The environment and forests secretary also ordered demolition of concrete/paver block around trees, which stall their growth.