In at least two books of C. S. Lewis's Chronicles of Narnia, a group of "four trees" is mentioned.
Shortly after Digory has planted the tree to protect Narnia in The Magician's Nephew, his Uncle Andrew is brought forth to be shown to Aslan. Andrew Ketterley is put in a cage made of trees.
"Digory now saw that where four trees grew close together their branches had all been laced together or tied together with switches so as to make a sort of cage."
The Magician's Nephew
Then, when Peter, Susan, Edmund, and Lucy Pevensie are wandering about Narnia in The Lion, The Witch, and The Wardrobe, Mr. Beaver brings them into a spot to talk to them.
"Only when it had led them into a dark spot where four trees grew so close together that their boughs met and the brown earth and pine needles could be seen underfoot because no snow had been able to fall there, did it talk to them."
The Lion, The Witch, and The Wardrobe
My question is, are these two sets of trees the same? Both passages reference them being "four trees" and growing close together. The wording is also very similar.
Are they the same? Is it meant to connect the books? Or did Lewis just unintentionally use a similar landmark and similar descriptive language in two books that were years apart?