The forestry department on Thursday urged picnickers to respect the environment ahead of the Green Monday outing, which marks the start of the Lenten fasting period and traditionally people take to the fields.
People are urged not to cut wild flowers and shrubs, as many of them are endemic and strictly protected.
The department said visitors need to keep places clean and to collect all their garbage either by placing it in bins or taking it away with them.
If garbage is left behind in plastic bags there is the danger that it will be scattered by stray dogs, cats and foxes, the announcement said.
In some areas, pine trees are infected with a type of caterpillar that can cause skin problems.
“The public should be particularly careful to avoid sitting down near infected trees and avoid coming into contact with the caterpillar.”
Anyone who inadvertently comes into contact with the insect named the pine processionary (Thaumetopoea pityocampa) or its larvae, should seek medical attention.