Save the Euston and Somer's Town Parks

Euston Road and Hampstead Road are two highly polluted areas in Central London not far from the Telecom Tower.
12 to15 mature large trees in St. James' Gardens and several more in front of Euston station, highly valuable in combatting pollution damage to our health caused by constant heavy traffic, are to be cut down to make way for a HS2 which is being built to knock 20 mins off a journey to the West Midlands.
St. James' Gardens provides a very pleasant haven of tranquility in the midst of a busy, polluted area at the back of Euston Station and supports wildlife- young birds. Historic gravestones and a monument provide an impressive reminder of our history ( sailors intercepting slave ships) in the 19th century. I used to play there when I was a child on the swings, now replaced by a well-used sports pitch; a toddlers' playground also exists.
HS2 has been passed by Parliament but is there really NO WAY that this company cannot preserve the scarce bit of beautiful nature that has existed in this area for so many years and gives respite to so many?
Furthermore, Camden Council has, apparently of necessity, sold community green space to private developers. Again, in a built-up residential area, these green spaces are precious for adults and children alike : of course, it's the trees again which have to go to make way for the luxury flats. If you value peace of mind and your health, please sign this petition.
I can't tell you how much it means to me mentally and physically, to be in a beautiful, quiet space and, judging by the scarves which have carefully been tied round all the trees to be chopped; so do many others.