Changes in Orlestone Forest, Kent

Orlestone Forest, south of Ashford, was one of several forests used in a study of the effects of age and crop type on the ground flora of plantations (KIRBY, 1988). I repeated the Orlestone survey in 1991 and 1998 although this was not written up. The current visit (August 2022) was a chance to see what had happened to the stands since. In the following account compartment numbers refer to the 1983 stock map; the pictures from that time are scans of rather dark photographs (a pre-digital age and the flash on the camera did not work well).

Compartment 6a (p48 spruce stand, clear-felled by 1991). By 2022 there is a scatter of (planted) oaks emerging from a dense thicket of birch etc.

Compartment 6b (p47 Scots pine) has closed up again after the thinning in the late 80s; the broadleaved component encouraged by that thinning has been reduced; there is little on the ground with the low bramble of 1983 now just scattered plants.

Compartment 9a (p49 spruce, clear-felled pre1991). The 1983 stand had reasonable moss cover and a bit more field layer than the similar stand in cmpt 6a, but still generally less than 10% cover. Clear-felling led to more or less complete cover of grass and bramble; the growth of birch, willow etc with some emergent oak had created a dense thicket structure by 2022.

Compartment 9b (c.p15 oak, underplanted with beech, p50). The underplanted beech, combined with remnant hornbeam meant that this stand has always had a very sparse field layer cover. The young beech has thinned out somewhat; the oak still dominates the stand canopy.

Compartment 10a (p69 Corsican pine; thicket). In 1983 ground cover (c.30-40%) was declining under recently closed canopy. Felled post-1998. Now mixed broadleaved regrowth.

Compartment 11(c.1910/20 oak with hornbeam). In 1983 bramble was quite widespread, also at least locally some vernal species such as wood-anemone. In 2022 some areas showed low cover of bramble but where the hornbeam understorey was dense the ground cover was almost pure litter. Of course the vernal flora might still be good, since anemone would not be detectable in August.

Compartment 14b (p52 Douglas fir, recently felled in 1983 and replanted with Corsican pine). Not recorded in 1991 probably because it was impenetrable, but was done in1998 by which time the trees had largely closed canopy.

Compartment 15a.  (p61 Tsuga heterophylla in 1983; felled between 1991 and 1998). Most of this stand now seems to be a large permanent glade.

A feature of the Orlestone site are the chain-wide (22yds) bands of broadleaves that were left along the roads and in some cases round the outside of replanted stands.  Plots were recorded in some of these in 1983 (but not in the 1990s surveys) but they were little different to the old oak stands.  The dense hornbeam understorey tended to shade out the ground flora. There seems to be even less ground flora cover now.

The major factor determining ground vegetation cover is the light availability although an additional cause for change is the spread of deer since the 1980s (when deer numbers were low in this part of England).  Normally light levels are higher below broadleaved than coniferous stands but in this instance summer light levels in the broadleaved stands are also very low because of the dense shade cast by hornbeam and beech understories.  Many of the conifer crops have been removed since the 1983 survey, whereupon a grass-bramble cover develops until it is shaded out by the new tree growth.

The remnant oak-hornbeam strips and Compartment 10 appear to be much as they were nearly 40 yrs ago.The other stands cannot be said to have been restored to their former state: they lack the coppice structure and oak-hornbeam dominance. They are dense stands of birch with some emergent oaks, which are developing into broadleaved native high forest.

The original planting up of the wood in the 1940s and 1950s caused a dramatic change to the character of the site, but equally large changes have happened since. Forests, particularly where there is active management are not the unchanging landscapes, sometimes assumed.

KIRBY, K. J. 1988. Changes in the Ground Flora under Plantations on Ancient Woodland Sites. Forestry, 61, 317-338.

2 thoughts on “Changes in Orlestone Forest, Kent

  1. Yes, I am continually surprised, both by how some bits of wood look the same now as when I first saw them and then these blocks which look so different. It makes tracking woodland species changes more complicated!
    Keith

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