Remote mountains in Papua New Guinea (PNG) could be home to some of the world's tallest trees at extreme altitudes, scientists said Wednesday in a new study which questions assumptions about forests at such heights.

Trees situated at such altitude do not usually grow higher than 15 meters (49 feet), but scientists from Australia and Canada found that those in the Pacific nation's pristine highlands were as tall as 40 meters.

Some trees in Papua New Guinea's highlands are up to 40 meters tall. /AFP Photo

"Unexpectedly, forest biomass had a major peak at altitudes of 2,400-3,100 meters, an altitude where forests fail to grow more than 15 meters tall in other parts of the world," said Michael Bird of James Cook University.

The discovery questioned the established belief that "mountains make small trees" with forests at such altitudes often "squat and gnarly", author Michelle Venter from Canada's University of Northern British Columbia said.

"However, we recorded more than 15 tree families with individuals growing 30-40 meters tall at extreme altitudes, which brings this assumption into question."

The research team recorded more than 15 tree families with individual specimens growing 30-40m tall at extreme altitudes. /uq.edu.au

Scientists studied 195 forest plots in largely unresearched Morobe Province – from coastal lowlands at 50 meters above sea level to tropical forests at 3,100 meters – with their findings published in the Global Change Biology journal.

University of Queensland's John Dwyer said the study could encourage researchers to re-evaluate the ideal environments for growing very large trees.

"We got excited when we realized that the unique climate conditions found on the mountain tops of PNG were remarkably similar to those of temperate coastal areas known to grow the largest trees in the world," he said.

Such climates were not unlike those on the mid-west coast of the United States, home to large coastal redwoods, Dwyer added.

Researchers found that the unique climate conditions on the mountain tops of PNG were very similar to those of temperate coastal areas. /uq.edu.au

Giant sequoias, which are closely related to redwoods and found in California, are the world's largest trees and on average grow to more than 76.2 meters (250 feet), according to the US National Park Service.

(Source: AFP)