Simon Hodge said the successful tender for a new business on Forestry Commission Scotland's Glentress site - to be announced in January - had been chosen because of the need to raise money to maintain mountain bike trails.
The owners of The Hub cafe, which opened nine years ago at Glentress, near Peebles, have been told that their bid to run the new business at the Commission's new 9 million Glentress Peel visitor centre has not been successful, prompting vociferous protests from supporters who feel they have been badly treated. Emma Guy and Tracy Brunger, who built The Hub up from scratch and employ 30 staff, are due to leave the site in March 2012 when their lease expires.
Now, in an open letter to protesters, Hodge says: "I understand your disappointment that The Hub was not successful in the recent tender.
"However, I hope you can recognise that it would not be acceptable for a public body like Forestry Commission Scotland to reject other stronger bids for provision of services in the new facilities."
Hodge said the choice of bidder had been influenced by the need to make a greater financial contribution to the 250,000 cost of maintaining the trails at Glentress and the 7stanes network in the borders.
He said Glentress had grown massively in popularity, with visitor numbers approaching 300,000 a year, compared with 90,000 ten years ago.
"The new Glentress Peel has been designed to cope with this massive growth in popularity," he said. "All the new facilities are state of the art and geared for managing a large number of visitors to the forest."
However, he acknowledged the part The Hub has played in Glentress's success. "The Hub has also been an important part of the Glentress story over the last nine years."
Campaigners have vowed to fight on, saying Guy and Brunger should be allowed to stay. Guy said: "We are definitely fighting on. We might be out of the tender process but we still have next year."
Outdoors writer Cameron McNeish urged campaigners to continue their protests. He wrote: "Mountain bikers are incensed, claiming that the Forestry Commission is ripping the heart out of Glentress and that no fancy visitor centre could ever replace the warmth and welcome bikers get at The Hub."
On The Hub's Facebook page, David Pugh wrote: "This decision is disgraceful. I have ridden Glentress trails for the last ten years and enjoyed good food and chat in The Hub. New cafe will be boycotted for sure."