Suzanne Bowyer said it was usually "your knickers or bra" tied to the top, although others mentioned pantyhose or "grey stockings".
Robin Evans believed the school turned a blind eye, but you had to watch out for the matron.
Ann Hay said: "There was a bra at the top that flapped quite pinkly for quite some time."
She remembered grey stockings or pantyhose being used.
Diana Helen-Fairbrother said: "I can remember watching someone on the really skinny bit right at the top. I got up part way, but I got caught."
Several said a ladder was needed to get to the first branches.
Wendy Groves remembered a student getting some bruises.
"When I did it, someone hurt herself on one bit because the ladder had been taken away, so she had to drop the last bit. We had stolen the ladder from the swimming pool, but matron had taken it away."
The formal planting of the redwood was carried out by head girl, Rachael Whiteman, and the eldest "old girl", Pat Watts, 93, Lansdowne, who shovelled dirt into the hole where the tree was planted.
Principal Beth Rogerson, read prayers and the tree was blessed. She told the students "we're starting off our next 100 years, and doing it in a way that is meaningful, and related to education and growth of this college".
When asked by the Times-Age about the tree climbing stories she said "they are apocryphal stories" and nowadays "we would encourage students to keep their garments intact".
Mrs Hay said her time at the school was "a long time ago, but it only seems like yesterday" and she "loved it here".
"My mother would buy me all these boarding school books. I think she was brainwashing me to go to boarding school."
The Californian redwood (sequoia semperviren), can grow up to 115m and up 9m wide.
Its average lifespan is 600 years although they can live up to 2000 years old.
The redwood is naturalised in New Zealand, notably at Whakarewarewa Forest, Rotorua. Redwood has been grown in New Zealand plantations for over 100 years.
Wairarapa Archivist Gareth Winter said redwoods were "very popular" as a specimen tree for early settlers.
Wairarapa colonist Donald Donald planted the Solway College redwood tree on his 100-acre property, called Solway.
The college opened on February 8, 1916.