By Manuel Ausloos
PARIS (Reuters) - As a third heatwave baked France this week, the heat radiating off the asphalt outside the Garnier Opera house in Paris hit 56 degrees Celsius on urban planning expert Tangui Le Dantec's thermometer. Shade was non-existent with barely a tree in sight.
The Place de l'Opera is one of numerous so-called urban heat islands in the French capital, lacking the trees that cool cities down by providing shade and seen as a key line of defence against climate change and increasingly hot summers.
Just a minute's walk away, in the shade along the tree-lined Boulevard des Italiens, Le Dantec's thermometer gave a reading of 28C (82 degrees Fahrenheit).
"Immediately there's a bit of a breeze. You can breathe," Le Dantec, who founded Aux Arbres Citoyens, an action group opposed to tree felling.
Paris ranks poorly among global cities for its green cover. According to data from the World Cities Culture Forum, only 10% of Paris is made up of green space such as parks and gardens compared to London at 33% and Oslo at 68%.
Last month was the hottest July on record in France, according to the national weather agency Meteo France, the searing temperatures underlining the need to strengthen the capital's natural defences against global warming.
Paris City Hall wants to create "islands of freshness" and plans to plant 170,000 trees by 2026. It is also ripping up the concrete in dozens of school yards and laying down soil and vegetation.
"It's a massive tree and vegetation-planting project that is underway, much bigger than under previous administrations," said Jacques Baudrier, deputy Paris mayor tasked with the green energy transition in buildings.
However, City Hall's green ambitions have provoked some protests. Le Dantec and other ecology campaigners say the local authorities have been felling scores of decades-old trees to make way for garden spaces.
In redrawing the city's landscape, the felling of mature trees runs counter to the authorities' own ambitions as saplings are more vulnerable to drought and less useful in fighting heat radiation, green activists say.
In April, green activist Thomas Brail shot video of more than 70 trees being felled on the city's northern outskirts to make way for Mayor Anne Hidalgo's vision for a "green belt" around the city.
City Hall's urban planners say Paris cannot be redesigned to better confront climate change without felling some trees.
But Brail said: "These trees had a role to play."
(Reporting by Manuel Ausloos and Lea Guedj; Editing by Richard Lough and Janet Lawrence)