 A closely related approach to forest management is Continuous Cover Forestry (CCF), which makes use of selection systems to achieve a permanently irregular stand structure.Selection cutting or systems are generally considered to be more challenging to implement and maintain than even-aged management, due to the difficulty of managing multiple age classes in a shared space, but there are significant ecological benefits associated with it.Uneven-aged stands generally exhibit higher levels of vertical structure (key for many species of birds and mammals), have higher levels of carbon sequestration, and produce a more constant flow of market and non-market forest resources than even-aged stands.