Long-term changes in the flora of oak forests and of oak:spruce mixtures following removal of conifers

Abstract

Ground vegetation changes under coppice regimes have been well described but less work has been done in Britain on the changes that take place under managed high-forest. In 1982/3 15 sixty 14.1 x 14.1 m quadrats were recorded across stands of oak (Quercus robur L.) and spruce (Picea abies (L.) H.Karst.)/oak mixtures, of various ages in Salcey Forest, southern England. In 2014 the survey was repeated and changes in the ground flora over this 31year period in the different crop types were compared. There was a decline in the species richness (number of species per quadrat) in most stands, mainly of species with a high Ellenberg light score, even under mature oak (>100 years old) where no intervention had taken place. Plant species richness increased in stands that had been felled or heavily thinned. The flora of stands where the spruce had been removed leaving a predominantly oak canopy had become similar in richness and individual species frequency to the mature oak crops, supporting the case for restoration of plantations on ancient woodland sites. The changes in the frequency of Woodland specialist plants were similar to those for other woodland species.

Restoration of broadleaved woodland under the 1985 Broadleaves Policy stimulates ground flora recovery at Shabbington Woods, southern England

“…Kirby and May (1989) found increases in species richness and ground cover in the first few years in restored stands at Dalavich Wood in Argyll, suggesting that restoration could be successful. Similarities between restored and remnant oak stands in terms of species richness and the type of species present have since been found at Salcey Forest, Northamptonshire, in a parallel study to this one (Kirby et al, 2017). There was little indication at Salcey that woodland specialists had changed in abundance differently to other species and at Shabbington Woods the specialists were the most likely group to be found in both surveys.…”

“…In the Shabbington Woods and in a parallel study at Salcey Forest (Northamptonshire) (Kirby et al 2017) reductions in species-richness at the quadrat were observed in more stands than showed gains in species. This parallels declines reported for largely-unmanaged broadleaved woods across England based on a comparision of records from 1971 and 2001 (Kirby et al, 2005), and at Sheephouse Wood which was sampled more regularly from 1981 to 2012 (Kirby, 2015).…”

Can epiphytic lichens of remnant Atlantic oakwood trees in a planted ancient woodland site survive early stages of woodland restoration?

“…Despite the short duration of our study relative to the timescales of woodland establishment, vegetation in the former plantation showed development towards a species assemblage characteristic of the remnants. Such an outcome has been shown to take place over periods of a century or more (Kolk and Naaf 2015;Naaf and Kolk 2015) but as Kirby et al (2017) reported, ground flora resembling that of an oak woodland developed over a period of c.30 years close to rows of oaks, following restoration of mixed, Norway spruce (Picea abies)-oak woodland. From this, we conclude the proximity of remnants to former plantation at our study site is enhancing the rate of indicator plant colonization.…”

“…Restoration success is frequently assessed using vascular plant species (e.g. woodland canopy species and ground flora) and diversity, and occasionally by use of growth form and growth traits to elucidate succession and community function (Grime 1977;Polley et al 2005;Pfestorf et al 2013;Kirby et al 2017).…”

“…Within PAWS, the ground flora of ASNW Atlantic oakwood areas and remnants provide the indicator species, measures of richness and profiles of traits against which progress of PAWS restoration towards Annex 1 Habitat 91A0 can be assessed (Kirby et al 2017;Shackelford et al 2013). However, the actions undertaken in restoration may be detrimental to alternative guilds occupying the oakwood remnants which could be considered a conservation priority.…”