Dr Robin Pellew, chief executive of the National Trust for Scotland, resigned last week, claiming weariness with its persistent financial problems.
The newspaper Scotland on Sunday alleged that the trust was weathering a financial crisis and that Pellew, a former WWF-UK chief, was unable to "face another term sorting out its difficulties".
Pellew was brought in five years ago to undertake a major review of the charity's operations and is credited with modernising the trust. A spokesman for the trust denied it was in financial crisis and said: "Dr Pellew felt now was the right time to hand over to a new team to lead the next phase of activity."
Shonaig Macpherson has been appointed the interim executive chairman.