He said the tree is dying so filling with cement give it energy to survive
Nathan Radley fills the knothole in the tree with cement, preventing the children from receiving gifts left by Boo Radley.
Nathan Radley said that when a tree is dying you fill is with cement to save it.
Nathan Radley tells Jem that he filled in the knothole with cement because the tree was dying and he wanted to stop it from spreading. In reality, he likely did it to prevent Boo Radley from continuing to communicate with the children.
Mr. Radley puts cement in the knothole to prevent any further communication or interaction between Boo Radley and the children. This action is driven by his desire to isolate Boo Radley from the outside world.
Nathan Radley fills the knothole with cement to prevent the children from seeing into the house.
In "To Kill a Mockingbird," the knothole in the tree is cemented up by Nathan Radley, Boo Radley's brother, as a way to prevent Boo from communicating with the children. This action symbolizes the Radley family's attempt to isolate Boo from the outside world and maintain their reclusive lifestyle.
Boo Radley leaves gifts for the children in the knothole of the tree.
They can not because the knothole is filled with cement by Mr. Radley
He tells them the tree is dying.
Nathan Radley knows Boo has been leaving gifts there for the children so fills the hole in with cement. When the children enquire as to why he's doing this, he lies and says that the tree was dying and this would save it.
Nathan Radley, Boo Radley's brother filled the knothole with cement. When Jem and Scout asked him why he was doing this he told them that his tree was dying and filling the knothole with cement would keep it from dying. Scout and Jem went and asked Atticus if he thought the tree looked like it was dying and he said it looked perfectly healthy.
Nathan Radley fills the hole in the tree where gifts are placed with cement to keep Boo from communicating with the children.