Betty Dawes was president of the Southwick Community Association from 2007 until her death in May 2016 and many years earlier, was one of the band of volunteers who helped with the conversion of the Barn Theatre, part of the centre.
The three resident theatre companies decided to raise money for the tree and held a memorial concert last year.
Betty was a central figure in Wick Theatre Company and Southwick Opera, which were joined by Southwick Players for the concert and tribute.
Widower Ralph Dawes and their family joined members of the association and the theatre companies to see association chairman Bob Ryder unveil a plaque dedicating the tree to Betty.
Bob said the tree was a Chanticleer ornamental pear, which grows in a neat oval shape. It produces glossy green foliage early in spring, followed by white flowers, and its leaves turning to orange-red in late autumn.
Bob also spoke of the fascinating history of the area, explaining farm buildings in what is now the car park had become derelict by the 1930s and an old fig tree was growing near this particular corner.
Ted Heasman, local historian, remembers scrumping the fruit and climbing into the branches to watch firemen dealing with a nearby blaze.
The fig tree disappeared in the mid-1960s but has now been replaced in a new and decorative form.
Ralph said Betty was an active volunteer at the community centre from its early days. She worked long and hard to help clear the old barn in 1951, so it could be turned into a theatre.