Scotland's Munros have become home to 'record-breaking' trees, new research has found.
Trees have been found growing atop the mountains which are higher than 3,000 ft - setting new altitudinal records for a number of species.
The discovery, made by a PhD researcher at the University of Stirling, could help shape a new understanding of the environmental limits for the species and have an impact on rewilding.
It will help make strides towards restoring our natural treelines after human activity saw the loss of woodland and montane scrub across most Highland hilltops.
The highest was a rowan growing at 1,150m (3,773ft) near the top of Sgurr nan Ceathreamhnan in West Affric.
Some of the perennial plants were found growing 200m (656ft) above previously known altitudes.
READ MORE: Hillwalkers being recruited to bag a Munro - in the name of science
Others included a Sitka Spruce thriving at 1,125m (3,691ft) on Braeriach, the third highest mountain in Britain, and a Goat Willow at 984m (3,228ft) on Beinn Eibhinn.
Sarah Watts gathered the information by scrambling up hundreds of mountains with the required elevation.
“I have now bagged more than 200 Munros although I must admit I did lose count because I am more concerned with recording the distribution and altitudes of trees and other mountain plants," she said.
“It was fascinating to find trees growing at the absolute limit of environmental tolerance for these species. Some were 200m above previously known altitudes.
“This shows us that there is potential for woodland restoration in Britain’s mountains after centuries of habitat loss and degradation.”
The researcher, who is a part of the university's Faculty of Natural Sciences, was also assisted by citizen science.
Dozens of Munro baggers and hillwalkers informed the research by sending on photographs of trees growing near summits on social media using the hashtag #highmountaintrees.
She also set up the Facebook group High Altitude Trees of Britain and Ireland where members can provide information.
Ms Watts then verified the altitudes of the individual hardy plants using a handheld altimeter.
The research, which was published in an online journal titled British and Irish Botany, uncovered 72 trees growing above the 900m threshold.
READ MORE: 'Absolute disaster': Concern after Highland lochan drained of water
Sitka spruce was the most common record-breaker and made up more than half (56%) of the discovered species.
The coniferous evergreen tree is known to grow almost 100 metres tall, but many of the discovered plants were small and stunted.
A total of eleven species were found at heights that marked altitudinal records for Great Britain.
The non-native plant is less appealing to large herbivores as well as being able to withstand high winds and nutrient-poor soils.
These were the following: rowan tree, Sitka spruce, wholly willow, eared willow, downy birch, whortle-leaved willow, tea-leaved willow, goat willow, aspen, silver birch and lodgepole pine.
Ms Watts said: “These data on altitudinal ranges help us understand the environmental tolerances of plants and how climate change or land management may be influencing their distribution.
“This research will also help inform my PhD project focusing on mountain woodland restoration and conservation management to reinstate the natural altitudinal treeline.
“These high-altitude habitats have largely been lost across the Scottish Highlands due to overgrazing of livestock and deer, but can be havens of biodiversity providing benefits for wildlife and people including natural hazard protection, sheltering, and flood-risk reduction.”
The records are in part attributed to marked changes in land use and grazing management that have allowed the natural regeneration of trees and shrubs.
It is not the only case of Scots helping make new discoveries across the country's highest mountains.
We previously reported that scientists are also recruiting hillwalkers to help create the first map of alpine soil biodiversity across the peaks.
Walkers will be armed with sampling kits for use between June and September this year and next.
The samples will help scientists at The James Hutton Institute unearth the secrets of a hidden realm of organisms including bacteria, fungi, nematodes, worms, mites, springtails and others.
The project follows a successful pilot in 2021, which saw 219 samples collected from 55 Munros in the Cairngorms National Park, uncovering an incredible 2,748 fungal species, two of which were new to the UK and another previously unknown to science.
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