Three nine-year-old cricketers who were injured when a tree fell as they waited to use practice nets have been named by their sports club as Lewis Gaston, Aidan Oakley and George Roberts.

Two of the boys suffered serious head injuries and the other suffered leg injuries when the tree fell at Spencer cricket club in Earlsfield, south-west London.

Aidan has been discharged from hospital while Lewis and George are remaining under close observation, the club said.

Members of the senior team were playing a match against Cheam Cricket Club when the tree fell on Saturday.

The club said in a statement: "We understand that their condition is improving and we hope that they will continue to improve and make a full recovery. Our thoughts are with them both and their families. At this time, the club would like to place on record its sincere thanks to those people who responded so quickly to this terrible accident and who ensured that the injured boys would have the best chances of recovery.

"The coaches and parents who were at the training session who reacted so quickly to a very serious situation; the players and spectators from Cheam and Spencer cricket clubs who were playing at the ground at the time who were able to lift the tree and free the trapped boys; the doctor who was present at the ground who administered emergency care; and the police and ambulance services who arrived within minutes to take the children to hospital. We are extremely grateful to them all."

Monique Wilkinson, 33, was staging a birthday party for her three-year-old daughter at her home when she heard the tree fall. She said: "We could see the kids stuck under the tree and there were a lot of people around. It's terrible. These kids play on the field every weekend.

"The air ambulance landed in the field across the road from us and there were four or five ambulances in total. The emergency services seemed to have everything under control. Another tree came down on this road earlier in the day which shows how bad the winds were."

Charlie Masson-Smith, from Wandsworth council, said the wind was very strong and could have knocked down a healthy tree.

"This was at a private cricket club but from what we have been told there were a bunch of kids queueing up to go in the nets. All of a sudden this tree came down on them," he said. "The council does not have any role to play, it is a private tree on private land, but it has been pretty windy in town and you can have a really healthy tree but if the wind catches in a particular way, a healthy tree can be blown over. It is a terrible accident."

Spencer cricket ground is home to the private Spencer Club, a sports club with more than 500 members, offering cricket, tennis, squash, hockey and lacrosse. According to its website, the Spencer Club was founded in 1872 when John Poyntz, Earl of Spencer and great-great-uncle of Diana, Princess of Wales, owned the land. He permitted the founders of the club to drain part of Wandsworth Common and erect posts for cricket, and the club was named in his honour. It moved to its present location at Fieldview in 1903.