KEY POINTS:
Chatham Islands trees bearing rare and distinctive Moriori carvings are fast being destroyed by voracious beetles.
The Moriori were thought to have settled on the islands about the same time Maori arrived in mainland New Zealand.
They created possibly thousands of carvings on the trees - the only people known to have carved living trees, Ministry of Agriculture and Forestry magazine 'Biosecurity' reported.
Although it was unclear exactly how many carvings were made, it was apparent there had been a rapid rate of loss over the last hundred years.
In the 1940s and 50s there were possibly more than 1000 carvings left, and today the number has been reduced to a few hundred.
One of the culprits, along with land clearance and animal damage, has been identified by Maf Biosecurity staff as the pinhole beetle.
Staff who visited the Hapupu Reserve and discovered several of the large carved trees were under attack by the beetle.
The beetles were initially attracted to volatile compounds given off by stressed trees.
If the tree was found to be suitable, the first arrivals emitted an "aggregating pheromone triggering a mass attack", the magazine said.
At that stage, the tree's natural defences usually failed, and it succumbed to a combination of wood boring and fungi.
- NZPA
