Woodland Trust Scotland said "spadefuls" of bluebells had been removed from the stunning Kinclaven bluebell wood in Perthshire.
The destruction was discovered by nature lovers visiting the site early on Wednesday, May 15th.
The Trust, which bought the wood for £740,000 in July 2017, thanks to a generous legacy, has reported the incident to Police Scotland.
A Police Scotland spokeswoman confirmed the incident had been reported, adding: "We are aware of the matter".
UK bluebells are protected by the Wildlife and Countryside Act (1981), which prohibits anyone from digging up bulbs in the countryside and landowners from removing bluebells from their land for sale.
The species was also listed on Schedule 8 of the Act in 1998 which makes trade in wild bluebell bulbs or seeds an offence punishable by fines of up to £5,000 per bulb.
Kinclaven's bluebells have been described as "simply breathtaking", and "a blue haze which seems to go on forever".
Woodland Trust Scotland only this week launched an appeal for people to respect the flowers following reports of trampling - some in a quest for picture perfect selfies - as carpets of the violet blue flowers hit their peak across Scotland, including Kinclaven bluebell wood.
George Anderson, of Woodland Trust Scotland, said: "Trampling is one thing but lifting bulbs is theft and raises the situation to a criminal offence.
"Whether taken for commercial gain or for someone’s own use, this is a selfish act. These wild bluebells belong in this ancient wood -- not lifted and touted around like bedding plants from a garden centre.
"The matter will be reported to the police and we will be increasing vigilance at the wood. If anyone has seen this spadework happening or knows anything about who is responsible we urge them to contact the Police."
The oak wood, previously known as Ballathie Bluebell Wood, is said to have given Sir William Wallace and his army shelter after they attacked the English garrison at nearby Kinclaven Castle and burnt the fortress following a siege in 1297.
The site comprises a 125-acre ancient oakwood called North Wood, where it is thought Wallace hid, and 79 acres of grassland known locally as Court Hill.
Woodland Trust Scotland, which manages 60 sites covering more than 8,000 hectares across Scotland, is working to secure and enhance the woods with native trees, as it would have looked in Wallace's day, and reforest adjacent grassland cleared of trees in the 1940s and 50s.
Around half of all bluebells in the world are found in the UK, and carpets of the violet blue native flowers are about to hit their peak across Scotland.
Bluebells -- also known as wild hyacinths -- thrive in old broad-leaved woodlands where trees are far enough apart to allow light to reach the ground.
The iconic blue-purple flowers traditionally begin blooming in the warmer south around April and the shimmering carpets spread further north as the season progresses.
Around half of all bluebells in the world are found in the UK and Scotland's native species (Hyacinthoides non-scripta) is protected.
Because they are strongly associated with ancient woodland, carpets of bluebells in a wood are likely to signify the wood is also ancient.
Spanish bluebells also flower at this time of year but is simple to differentiate from native species. The Spanish bluebell is more upright with flowers on both sides of the stem, while the British bluebell leans over, weighed down by its flowers all on one side.
In Scotland, the harebell (Campanula rotundifolia) is also referred to by many people as the "Scottish bluebell".