After the Second World War, work started again, although the years of neglect had left the tree cathedral very overgrown. Regular assistance in the clearance was given by Gerald Wallsam, who is commemorated in Wallsam Way. Another dedicated assistant was William Baldwin.
By 1952, enough of the resulting undergrowth had been cleared to hold ecumenical services. In 1960, a generous legacy enabled Mr Blyth to present the plantation to the National Trust, with a covenant allowing trustees of the Whipsnade Tree Cathedral Fund to continue its upkeep and organise services.
The only change to the original plan has been the addition of the hornbeam avenue from the car park. This was in memory of Mr Blyth's son Tom who managed the Tree Cathedral after his father's death in 1969, until his own death in 1978.
After Gerald Wallsam passed away in 1983, the endowment fund was reorganised, enabling the present high standard of maintenance to be developed. The present trustees continue to manage the site with the help of regular volunteers, local contractors and professional foresters, as well as the rangers of National Trust Bedfordshire Properties.