Temperate Forest Ecology

Very little remain of the original native Irish forests. Some stands of semi-natural woodlands are still found on unproductive land, especially scree slopes. These woodlands are characterized by a lack of regeneration of native shrub and tree species and in many areas by the spread of a number of alien species. Woodlands are usually overgrazed but when herbivores are excluded little regeneration takes place as succession is often prevented by dense grass swards.

Following an investigation of the age structure and natural regeneration of a semi-natural woodland (see Binggeli & Rushton 1985) a long-term monitoring of girth increment growth in the four main deciduous tree species was initiated in 1984. This project examines the effect of climate on tree growth.

Even in the absence of grazing native trees often fail to regenerate. Where regeneration takes place, it is usually limited to the close vicinity of fruiting trees. On an abandoned escarpment on the north coast of Ireland the regeneration of ash (Fraxinus excelsior) is being investigated in relation to the gender and spatial distribution of mature trees.

Vegetation succession on sand dune systems has been investigated with special reference to the establishment of woodland following the spread of sea buckthorn (Hippophae rhamnoides) thickets.

The autecology of a number of native (Hedera helix, Pteridium aquilinum) and invasive woody plant species is being looked at in detail.

Birch-rowan hazel woodland at Murlough Bay (Co. Antrim) (21702 bytes)

Secondary succession dominated by Fraxinus excelsior and Ulex europaeus (yellow flowers) in the north of Ireland. To the left of the stone all grazing seized in the 1960s and the regeneration is dominated by F. excelsior whereas to the right light grazing by horses has resulted in extensive regeneration of U. europaeus as well as of F. excelsior. (116095 bytes)

Broadleaf plantation at Murlough Bay, Co. Antrim, Northern Ireland. Note the absence of regeneration.