Jem and Scout discovered that someone had filled the knot hole with cement, sealing off the opening where gifts had previously been left for them by Boo Radley. This action by Nathan Radley signified the end of their secret communication with Boo.
Nathan Radley filled it with cement
Nathan Radley fills the hole in the tree where gifts are placed with cement to keep Boo from communicating with the children.
The cemented hole in the tree represents Boo Radley's isolation from society. Nathan Radley fills the hole with cement to prevent Boo from communicating with Jem and Scout. Jem is heartbroken because he realizes the cruelty of this action.
Nathan Radley claims he is filling the knot hole in the tree with cement to protect the children from any future presents being left for them. However, his true motive may be to prevent Boo Radley from communicating with Scout and Jem.
Nathan Radley tells Jem and Scout that he filled the knot-hole with cement because the tree was dying and he didn't want it to fall on someone. However, it is later revealed that he filled it to prevent gifts being left for the children by Boo Radley.
He said the tree was old and it was dying and that people fill trees with cement when they're sick.
Mr. Radley filled the knot hole with cement to prevent Boo Radley from communicating with the children. He believed it was for their own safety and to keep Boo isolated from the neighborhood.
Nathan Radley seals the knot-hole in the tree in front of the Radley place because he believes it is a bad influence on Boo Radley and wants to cut off communication between Boo and the children. He fills the hole with cement to prevent gifts being left for Boo.
Mr. Radley put cement in the tree's knot-hole to prevent Boo Radley from communicating with the children through the knothole. It was a way for him to cut off Boo's only form of interaction with the outside world.
In "To Kill a Mockingbird," Nathan Radley fills the knot hole of the oak tree with cement to prevent Boo Radley from communicating with the children by leaving small gifts. This action is a way to isolate Boo further and maintain his seclusion.
Jem is upset and saddened by Nathan Radley's action of cementing over the knot hole in the tree as it was a special, secret spot where they used to find small treasures. He feels a sense of loss and violation of their childhood memories.