Dartmoor National Park has granted the Ministry of Defence (MoD) a "temporary" permission to use moorland for training exercises which will run until 2053.
Campaigners feared the "peace and tranquility" of the wilderness could be destroyed if the arrangement with the MoD was put on a "permanent" basis.
An MoD application to continue to use Cramber Tor, on the south west of the moor had attracted widespread opposition from environment groups who fear that up to 700 personnel could be involved in mock battles on the sensitive site.
Members of the governing authority yesterday ruled on the request for an indefinite permission and instead allowed a limited time period of 40 years, subject to a number of conditions.
Bill Hitchins, authority chairman said members had listened to the public outcry and decided not to grant permission "in perpetuity".
He said exercises could continue but the environmental impact of the training would be monitored.
Mr Hitchins added: "In granting a temporary permission we have balanced the need for military training to support and equip our armed forces with the long-term purposes of the National Park.
"The temporary permission granted means that there is a long-term stop date and allows an opportunity for formal re-assessment of the case for continued training at that date.
"I sincerely hope that there will come a time when the military no longer needs to train on Cramber Tor as it hopefully means we live in a more peaceful world.
"Until that time we will continue to work with the military to minimise their impact and ensure the public's enjoyment of this special place is not spoilt."
The MoD has been using 2.095 acres of moorland since 1981 but a change in the law, which removes Crown immunity for planning, required the formalisation of what had operated as "almost a gentlemen's agreement".
James Paxman, chief executive of the Dartmoor Preservation Association, said he had been "deeply concerned at the possibility of battle simulation" which would "destroy the peace of this tranquil area".
Ahead of the meeting, he called for new conditions to be imposed to limit the number of troops, aircraft, and the use of pyrotechnics.
Whilst not all of these were agreed, conditions were imposed to prevent training in August, on Sundays or Bank Holidays.
The number of training days a year was also limited to 40 "man-training days" with groups no bigger than 35.
An authority spokesman said the challenge was now how to mitigate the effect on the environment, wildlife and people.