Are cypress leaves are edible

Cypress leaves are not normally eaten. However some are used for their medicinal properties e.g. A decoction is made from the leaves of Monterey Cypress (Cupressus macrocarpa) for the treatment of rheumatism.

The White Cypress (Chamaecyparis thyoides) has been used medicinally too. A decoction of the leaves has been used as a herbal steam for treating headaches and backaches.

This would indicate that the leaves, at least of some cypress, are not poisonous. It may well be that they are not eaten simply because they don't taste very nice.