This word has rather obscure etymology, but may, through its meaning of a sunny place in the woods, be related to “gleam”!

• 03.012 when they came at length to an open glade
• 06.052 and they ran to the trees at the edge of the glade,
• 06.052 a large pine standing at the very edge of the glade.
• 06.060 This glade in the ring of trees
• 06.060 in the glade;
• 06.065 Very soon all about the glade wolves were rolling over
• 08.099 in the glade where they lived,
• 19.001 into the lower glades of the wood

“glade, n.2.” OED Online. Oxford University Press, June 2015. Web. 26 July 2015.