They found a spot away from the glen where the fire wouldn't catch on to the trees.
8 seconds sound clip from the Frosty the Snowman (1969) movie soundboard.
You can hear this line at 00:16:19 in the Blu-ray version of the movie.
Quote context
[...]
- Then suddenly they came upon a tiny glen which seemed almost magical.
- For it was Christmas eve and the woodland animals were all decorating for their big celebration.
- They knew Santa was to come that night and they wanted everything to be just right.
- Speak to the animals. See if they won't all pitch in and build a fire for Karen.
- The animals were delighted to help.
- They found a spot away from the glen where the fire wouldn't catch on to the trees.
- Soon there was a spark and in almost no time a splendid fire was crackling away.
- Frosty was careful to stay far away from the flames.
- No, not the president of the United States.
[...]