She can barely remember what she had for lunch five minutes ago but her sensorial memories of our expeditions up the Arrow River to the site of the old gold mining ghost town were astonishingly detailed.
She wanted to feel the smooth rocks on her bare feet as we forded the river, taste the tart gooseberries and sweet raspberries growing wild and dusty on the side of the track and smell the pastel-coloured lupins which appear every year from nowhere.
She couldn't see the geckos sunbathing on the warm rocks, the play of light on the golden tussocked hills or the dark shadows cast by the high mountain ranges and deep gorges.
But she remembered the distinctive smell of cold river water on hot schist and the shimmery silver powder of the river silt on her skin.
There were tears in her eyes as she relived the discovery of a horse's skeleton in an old hut near Macetown. The wretched animal must have wandered inside in search of shelter from the snow or rain or sun, and become trapped when the door blew shut. The poor creature would have starved to death standing upright.
Macetown was much as Mum remembered - a peaceful place with remnants of a main street, stone walls and fruit and shelter trees where cottages once stood. Dad used to make a little fire to "boil the billy" for a cup of tea and we ate sandwiches and apples under the trees.
The town was first settled in the early 1860s as a result of the discovery of gold in the Arrow River. At first the rush was for alluvial gold from the river. Later the miners turned their attention to the hills and several quartz mining operations were established. But when the gold ran out, the town slowly died and by the 1930s, Macetown was just a ghost town.
A project completed in 2008 carefully restored an old cottage, bakehouse and quartz-crushing battery, the only known all-metal stamping battery in Otago.
The 24 river crossings Mum remembered so well are now reduced to a handful, thanks to new bridges and a track cut around the hillside - but I didn't tell Mum that. She would have considered that cheating.
And I certainly didn't confess that on the way back from Macetown, we hitched a ride in the lead vehicle of a 4WD club whose members were having huge fun fording the river and negotiating the steep, narrow, former dray track.
In our defence, we were running short of water on a scorching hot summer day so accepting a ride was the sensible thing to do - and the gremlins had obviously been playing with my memory too because the track seemed longer, steeper, dustier and hotter than when I was a youngster. So much for that song about Christmas trees being tall when we were small and small when we were tall.
At the end of the day, we sat outside a lovely cafe in Arrowtown in our tramping gear, drank ice-cold lager and demolished a plate of hot chips - Mum would have loved that.
In her mind, our crib is still there, on the hill in Arrowtown with a view from the kitchen window of the lopsided crown on the Crown Range - there's a smart new holiday house there now but she didn't need to know that.
As we pitched our little tent at the upmarket camping ground with its five-star kitchen and ablution facilities, I struggled to recapture the fierce sense of ownership I have always felt for Arrowtown. But when we left two days later, I felt like a visitor, an outsider. I didn't belong there anymore.
Then all of a sudden, rather than feeling sorry for Mum, I had an overwhelming sense of peace about her. She still lives there - and I don't.
- nzherald.co.nz
