Long-term patterns of mortality and regeneration in near-natural woodland

1. Long-term patterns of natural regeneration, growth, mortality and disturbance were recorded in six native lowland woods around Britain, using a series of permanent transects/plots established during the 1950-80s. Records were made including the position and status of trees, shrubs, established seedlings, dead wood and canopy gaps.<br></br>2. The stands inherited various original-natural features and grew away from a managed state. Nonetheless, their structure and composition remained heavily influenced by past treatment and non-native species.<br></br>3. The natural development of five woodland types and twelve tree and shrub species was reviewed and four general stages of stand development were recognised.<br></br>4. The major processes controlling stand development were: (i) exclusion; (ii) damage caused by wind, drought, large herbivores and grey squirrels; and (iii) regeneration and release below part-broken stands and within/around larger canopy gaps.<br></br>5. The main structural changes identified during stand development were: (i) an increase in basal area to a maximum of c.30-50m² ha^-1; (ii) a decline in stem density until understorey reinitiation/gap-phase regeneration occurred; (iii) an increase instratification, especially under lighter crowned trees and once reinitiation/regeneration occurred; (iv) a scarcity of canopy gaps until at least 125-150 years growth, after which gap creation tended to be patchy and mainly associated with windstorms and drought,though an extensive blow down was recorded; and (v) a scarcity of dead wood until stands matured and broke-up.<br></br>6. Compared to other temperate forests, several distinctive aspects of stand development were recognised, particularly: (i) the role of large herbivores in delaying and altering regeneration; (ii) the importance of debarking by grey squirrels; (iii) the potential for some canopy gaps to fill other than with tree regeneration; (iv) the persistence of the understorey in certain native stand types; and (v) the vulnerability of mature beech stands to sudden and quite extensive collapse.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

The Open University

Year dc:date.issued

2005

Author dc:creator

• Mountford, Edward Peter

Language dc:language

en