https://www.scientificamerican.com/article/to-combat-climate-change-see-the-forest-for-the-trees/

When most people conjure a forest, they imagine a dense network of trees, their crowns arching high above, with spots of sunshine flashing between the leaves. Some might also think of birdsong and insects, or summon thoughts of thick foliage in the understory, the crunch of leaves or pine needles underfoot, or overgrown trails meandering into the thicket.

Whatever the particular imagery, it’s undoubtedly more picturesque that that conveyed by the United Nations Food and Agriculture Organization’s definition: An area greater than 1.25 acres, populated by trees 16 feet or taller, with more than 10 percent canopy cover. While this simple and straightforward list of attributes might make it easy to classify land, it gives little insight into what a forest can and should look like, which is important because recent research suggests that not all are created equal.