This picture is a little bit like the description, in some ways. https://www.birdandhike.com/Hike/Mt_Char/Bonanza_Pk/photos-bp-u/S120_22913a.jpg The description is poetic. In the picture, we see trees on a ridge. "The light is waning" means it is getting darker. The combination of darkness and long shadows suggests that we are getting near sunset, when the sun is low in the sky. The picture doesn't show that. In the picture, the light and shadow are almost "streaked as if cut with scissors." I'm not really sure what he means by "braided to the ridge, piece by piece." A person's hair is braided or plaited when it is twisted together to form long ropes; the hair is, of course, attached to the person's head. Something about the appearance of the streaks of light and shadows makes him think of them as being like long solid ropes or braids that are hanging down as if attached to the ridge line.

The land's angle became more severe[it refers to the incline or steepness, harder to travel through], the light waning, streaked as if cut with scissors and braided to the ridge piece by piece[waning refers to a decrease in intensity, the streaks referring how it comes through branches/obstructions].Soon poplars and hickories replaced the softwoods. [This talks about the difference in flora, so the first area had softwoods, as they kept walking, they now had poplars and hickories around them, all of these are different trees]

"The land's angle became more severe". This means that as the person travelled along the surrounding countryside had more hills, probably steep hills. "The light waned". This means it was getting darker and the sun was probably going down. "Streaked as if cut with scissors and braided to the ridge piece by piece". To me, this describes the light from the setting sun. The sunlight fell against the hills(ridges) in lines that twisted and curved. Hope this helps