A falling tree in a 1000 year old forest has revealed the existence of a rare shrub.

The shrub, Pittosporum kirkii, is one of four endemic to New Zealand and has been listed as at risk by the Department of Conservation since 2012.

The discovery was made at the Dansey Scenic Reserve outside Rotorua by Shelley Ogle, a tour guide at Rotorua Canopy Tours, who was conducting a tour when a tree fell next to the group she was with.

The trained ecologist was curious about the ancient tree and a closer inspection found a nest of perching lilly at the top of the tree, and a nest of Pittosporum kirkii.

"I posted a photo of the leaves and seeds to iNaturalist, and Nick Singers, a local ecologist who did Canopy Tour's recent ecology report, replied confirming it was a very rare shrub," says Shelley.

This rare and endangered plant is sometimes parasitic but in this case was using the ancient tree as a perch.

Shelley is positive about what this latest find means for reforestation.

"It's exciting because it shows how resilient nature is," she says.

"This reserve was struggling before Canopy Tours began its trapping program, and in only five years of the program, we've seen the return of many rare species in a now flourishing forest."

The Department of Conservation's local Rotorua office were notified and have confirmed it's a rare find.

Caraline Abbott, DOC's Community Supervisor in Rotorua, says this is a positive indicator for forest health in the Dansey Road Scenic Reserve.

"Canopy Tours' conservation efforts have seen some of the most successful regeneration of native flora and fauna in Rotorua. Our partnership with Canopy Tours has been successful in both bringing jobs to the region, and restoring the native forest's biodiversity," she says.

"It's really encouraging to find endangered species like these returning to the forest, it shows that trapping really does work and it massively benefits the native biodiversity of the area."

The shrub flowers later in the year, and Shelley was able to identify it by its thick leaves and bright yellow seed pod. Rotorua Canopy Tours will leave the fallen tree after assessing its safety impacts.

"When the tree fell, it knocked down some branches and perching lilies, once we clear those, we'll leave the tree to rot and return to the forest, it's all part of the natural cycle" says Shelley.

The discovery was also welcomed by Paul Button, Canopy Tours general manager, who says it affirmed their trapping efforts are having a real effect on the reserve.

"There aren't many recent records of pittosporum kirkii, so it's exciting to witness their return to this 1000-year-old forest," he says.

"Each sighting of an endangered species in the reserve just confirms that our trapping efforts are making a real difference to the region."

-Stuff.co.nz