I'm looking for a book I read back in school, probably in the period 1991-1996. What I remember of the book is:
- I think it's set in Sydney, Australia
- The main characters are a boy and a girl
- There's an old tree that's going to be cut down, and they're collecting signatures for a petition to save it
- They wind up going back in time - I think there's a tunnel in the roots of the tree that takes them back
- I'm pretty sure they go back to early colonial Sydney, and probably befriend a child of their age from that period
- The tree had a distinctive name, which I think was in the title of the book
There was also a computer game adaptation of the story that I played on the school computer.
- It was an interactive fiction game, with commands entered in the typical " " style (e.g. "look", "pick up rock", "go east")
- I remember there being primitive (monochrome) graphics but it's quite possible I imagined them - if they actually existed, then they were still images of the location you were at rather than being a map or anything similar
- The first part of the game has you going around talking to people to collect the signatures
- When you find the tunnel, you have to navigate it by following a light and the description is either something like "the light of the guides you to the north" or "you can't see the light of the " depending on whether you've gotten lost or not
I know that we had MicroBee computers as well as Apple IIe ones at various points, so it might have run on one of those, but there's also a small chance it was a DOS title so unfortunately that doesn't narrow it down much.