In the bush the dew settles on the trees, not on the fly. You can still get condensation but the dew won’t be adding to it.
On a dewy morning like today go for a walk and you will see the dew on the grass in the open area but not under the trees
This, plus the air will be a little warmer on dry ground under mature trees so the 'dew point' may not be reached, whereas the night draft draining down the valley will cool the air below the dew point even in summer.