Where a stem has discontinuous, overlapping successive periderms, patches of bark will form and can be shed. This is generally termed a scaly bark . Fissured bark has a net-like pattern from splitting of the outer and inner bark. Bast fibers, which formerly were widely used for making cordage and paper, give the trunk a very strong cover. Fibers would, on the one hand, give added strength for bending and limit stress on sieve tubes while also protecting the sugar-conducting sieve tubes of phloem, blocking sucking or burrowing insects.
Smooth barks can be smooth and very glossy to dull .
Generally these have a very thin outer bark. Some species of legumes also have peeling bark. As a tree increases in girth, great tension on the bark can cause vertical and horizontal cracking . Cracks may develop along planes of stress or more simply outline boundaries of scaly bark. These cork cells tend to have thin-walls and are filled with air.