unevenaged

Uneven-aged forests are stands in which trees of different ages and sizes coexist, maintained by harvesting methods that promote continuous regeneration rather than synchronized cohort establishment. This structure contrasts with even-aged stands that arise after clear-cutting or strong regeneration pulses, producing a uniform age class over a broad area.

Management of uneven-aged forests relies on silvicultural systems such as single-tree selection and group selection. These approaches remove trees individually or in small groups to create small canopy gaps, stimulate regeneration, and maintain a partially continuous canopy. Regeneration is typically natural, with desired species establishing in response to light gaps and seed sources; planting or direct seeding may be used to ensure representation of targeted species or to accelerate renewal.

Ecological and economic implications vary. Advantages include higher structural diversity, enhanced habitat value for many wildlife species, and greater resilience to pests, diseases, and windthrow through age and size diversity. Continuous forest cover can reduce soil erosion and support a more stable, if variable, timber yield over time. However, uneven-aged management often involves higher operational and planning costs, requires longer time horizons, and can lead to more variable wood quality and volume in the short term. Success depends on site conditions, species biology, and the availability of regeneration sources.

In practice, uneven-aged stands are common in many public and private forests where conservation, recreation, or multi-use objectives coexist with timber production. See also: selection forestry, differentiated rotation, and sustainable forest management.