What thing exactly? Inside a forest? Before a forest? How high/old are the trees? What trees? If theyre young, theyll be adversaries in themselves for anyone passing. Youll need to get the camera close to struggling chars faces. If the forest is high, old and theres now much shadowy space between leaf trees, its a completely different scene inside a cleared, churchlike hall. From outside on the other hand, youll see more leaves then trunks, eager to catch the sunlight. If youre in vicinity of a forest, maybe visit it and take pictures of the scenes fitting your story. Also check if the trees even fit to the climate in your story!
