In an age of emails and text messages, there is something intimately special and rare about handwritten letters.

Which is perhaps why, when an enterprising young girl wrote a colourful, illustrated letter to the then territory and municipal services minister about a tree that needed saving in her favourite park, Katy Gallagher chose to reply in kind.

Claire Stevens, 12, from Narrabundah, and Ms Gallagher, 42, Chief Minister of the ACT, have been exchanging letters as pen pals for about six months, each note more creative than the last.

"She'd drawn a picture of the tree, all in beautiful, coloured writing - she'd put a lot of effort into the letter,'' Ms Gallagher said.

"I had to compete with her - I did one letter in fluorescent markers, and she would come back with something better.'' For the Chief Minister, the letters became a ''nice leveller'', breaking up the frenetic day-to-day of politics and running the territory.

"Even during the election I remember doing one at about 4.30 in the morning,'' she said. "They always put a smile on my face.''

Both keep a collection of their correspondence, which includes Christmas decorations made by Claire and paintings by Ms Gallagher's children. Ms Gallagher keeps the letters in a box of keepsakes in her office.

As a relationship sparked by Claire's love of trees (while her favourite climbing tree was saved by one letter, the subject of her original note, alas, could not be saved, but was replaced with a new plant), it was appropriate that their first meeting was at the official opening on the National Arboretum on Friday, to which Ms Gallagher had personally invited Claire.

Her mother, Bernadette, said Claire had been saving up her first visit to the Arboretum, after it was mentioned as a good meeting spot in one of her letters.

So it was with legs of jelly Claire rose at 4.15am - the earliest she'd ever woken - to greet the sun and meet her equally-excited correspondent at an event that would be marked in Canberra's history.

There was a mutual synergy to their first face-to-face exchange, after the formalities of the Arboretum's opening had passed. While Ms Gallagher saw what had been achieved after years of hard work, Claire was looking ahead to years of playing among the trees and riding horses along the paths.

Both have said they will continue to write to each other.