Look up and you will see the gaps
Stand under a stand of tall TREES of the same kind and look straight up. In many woods the CANOPY is not a solid ceiling at all: each crown stops just short of its neighbours, leaving a river of sky running between them in a jigsaw of channels. Foresters call it crown shyness, and once you have noticed it you cannot stop.
Nobody is certain why it happens. The leading explanations are that branches whipping together in wind abrade each other's growing tips, and that trees can sense a neighbour's leaves from the quality of light bouncing off them and stop growing that way. Both may be true in different species. It is an oddly polite thing for something with no nervous system to do.
Woodland flowers are in a race, and they win it by starting early
By midsummer, only one or two per cent of the sunlight hitting the top of a broadleaved wood reaches the ground. Almost everything green on the forest floor is living in the SHADE on scraps. That is the reason a CLEARING where a tree has come down fills with growth so fast.
So the flowers do not wait. Bluebells, wood anemones and wild garlic push up, flower, set seed and die back within a few weeks in early spring — done before the LEAVES overhead have finished unrolling and the roof closes. The whole strategy runs on borrowed light, at the same moment the trees themselves restart photosynthesis after a winter off.
Some plants tell you how old a wood is
In Britain a wood counts as ancient if it has been continuously wooded since 1600, and you can often tell without looking at a single document. Certain plants spread so slowly that they cannot colonise a new plantation in any useful timescale — a wood anemone advances perhaps a couple of metres in a century, having largely given up on seed and grown sideways instead.
So a WOODLAND floor thick with anemone, dog's mercury and bluebell is very unlikely to be recent, and ecologists keep lists of these indicator species to argue against felling. It is a strange kind of evidence: the wood is proving its own age with flowers rather than with rings or records, and a replanted copse next door can look identical in summer and give itself away entirely in April.
The smell is a bacterium
That particular damp-earth smell when you step into a wood, or when rain hits dry ground, is mostly one chemical — geosmin, produced by bacteria living in the soil. Human noses are extraordinarily good at picking it up, down to a few parts per trillion, which is a far lower threshold than we manage for most things.
The rest of the grid is what you walk past on the way: the BARK and TRUNK, a fallen LOG and a tree HOLLOW, a snapped TWIG, FERN, MOSS, BRACKEN and IVY, an ACORN or PINECONE underfoot, the ROOTS lifting the PATH and a low BRANCH across the TRAIL. A FOREST is quieter than open ground too — soft ground and a million leaves absorb sound instead of bouncing it back.