Does taking pens from students in the classroom, against their will, constitute theft, thereby necessitating the estimation of their value and donating it as charity? And is someone who takes a plant from a public garden obliged to plant a tree in its place and care for it, or is it sufficient to buy any type of tree and hand it over to the garden’s caretaker?

Whoever seized something by force before reaching puberty is not sinful due to lack of accountability, but he must return the right to its owners. If it is possible to communicate with them, then either seek their forgiveness or return to them the value of what was taken from them. If it is not possible, then donate its value on their behalf. As for the usurped tree, the original ruling is to return its value at the time of taking it, unless it is highly probable that those in charge of the garden will not dispose of the value in a way that benefits the garden, in which case you must plant a similar one in its place.