(En Català: )

After pruning, the thickest branches need to be cut for firewood and the small branches should be burnt to avoid the presence of the Olive Bark Beetle, a beetle that grows rapidly in the pruning remains, and which can be bad for the olive grove. 
During the first year the branches that are still green need to be covered with plastic or canvas to avoid the proliferation of the olive bark beetle. The alternative method of spraying with pesticides is pernicious to the environment because when the branches are burnt they let of cancerous dioxines. 
English translation by Anne Kay (thank you Anne!)