It can change very quickly, when the whole forest becomes a single shade of green-brown under an imminent thunderstorm, or very gradually, as the sun progresses across the sky through a full day of riding.

It’s the difference between rolling into the trailhead with only the twilight to see by and the next morning, when the dew on the low grasses along the trail sparkles in the sunrise.   And sometimes it’s seemingly all you can see as it strobes through the trees along a ridgeline with your speed at sunset.The day’s light defines which facets of a trail are awash in highlights and which are obscured by shadow for the moment you roll over and through them. And because it’s so dependent on a set of ever-changing conditions, light itself makes it impossible to know an entire trail, even if you ride the same one everyday.