The company Roots to Shoots Limited has pleaded guilty to failing to discharge a duty under the Health and Safety Act.
A second charge, of breaching Health and Safety regulations, was dismissed after the crown offered no evidence.
The company had previously pleaded not guilty to both offences.
It was represented in court by advocate Jim Travers and Roots to Shoots director Christopher Preston.
Mr Travers said that a victim impact statement was being obtained by the prosecution and the defence would be providing financial information for the company as well as references before sentencing.
The incident is alleged to involve a motorcycle crashing into the back of a stationary vehicle at the back of a queue at Glen Helen on June 3.
It is alleged by the prosecution that signage was placed 148 metres from where tree-felling work was taking place, while health and safety regulations stipulate that it should be placed a minimum of 275 metres from the area.
Deputy High Bailiff James Brooks adjourned sentencing until August 23.
On its website Roots to Shoots describes itself as ‘the Isle of Man’s leading tree surgery and garden maintenance specialists, offering a range of services for both commercial and domestic customers’.