(An attempt to establish ground flora by introducing material from a known
In 2001 Kemerton
Conservation Trust began a small, practical trial to use leaf litter from local ancient
woodland as a method of establishing ground flora into modern planted woodlands on Kemerton
Estate, in South Worcestershire.
Trial plots were selected and prepared before the fresh leaf litter was raked
In 2004 the trial was extended and modified by using larger plots and by
improving the preparation of the ground. Then in 2005 bulbs and seed produced on the
estate were planted in very small plots.
The trial would assess the chances of success of a larger scheme on enriched,
former arable land and where grazing by rabbits and deer was difficult to
Annual monitoring of all plots took place and will continue – meanwhile this
report details findings to date, draws some preliminary conclusions and offers
A lack of funding meant that the trials would have ended prematurely but
English Nature (now Natural England) offered support via the Aggregates Sustainability
Fund – as part of a scheme to help develop this area of the estate as a nature
To date the trials indicate that very few species became established in the
new environment. In addition, grazing at levels found in the small plantations at
Kemerton may greatly restrict the diversity of plants able to colonise successfully. It
may be that only unpalatable species would survive.
Tree planting on Kemerton Estate began in the 1970’s
and has continued regularly since then. In some plantations, native trees planted under
early forestry grant schemes have since been under-planted with native shrubs. In later
years, new plantings included a shrub layer.
Thus, the basic ‘structure’ of the woodlands is in place but the ground flora
had not been considered and so is restricted to species spreading in from nearby
habitats. In most sites, which were adjacent to arable land, the flora is dominated by
Common Nettle but in a few, situated close to roadside verges, other species such as Violets
and Wild Strawberry have come in. In some plantations, after a number of years various
orchids such as Twayblade, Bee Orchid, Common Spotted Orchid and Broad-leaved Helleborine
The modern plantations were established on former arable ground and therefore on
enriched soils. Rabbits have long been a serious problem on Kemerton Estate, causing
great damage to crops. Although new tree plantings are rabbit proofed, the fencing
eventually fails and heavy grazing occurs. In recent years Roe Deer have moved in and
have increased the grazing pressure in the young woodlands. To what extent these
grazers might influence attempts to establish a ground flora was unclear but a small,
practical trial should establish what might be possible on a wider scale.
In 2001 Kemerton Conservation Trust (KCT) learned that a local woodland with a
rich ground flora, owned by Worcestershire Wildlife Trust, was to have an access track
upgraded. Identifying an opportunity to carry out translocation trials KCT was granted
permission to take suitable material from fresh ‘spoil’ heaps along the edges of the
track. In theory, the soil would contain seeds and bulbs of native plants that could
then colonise trial sites at Kemerton.
Four plantations, established between 1975 and 1985, were identified and a series of introduction
sites selected for the trials. These were chosen in an attempt to replicate the habitats at
the source sites, with regard to dominant tree species and light. All sites had been thinned
and the tree canopy had developed to shade out encroaching ground flora. In North Wiseacre,
the oldest plantation, further thinning and under-planting with shrubs had increased the available
light and here the ground flora consisted almost entirely of Common Nettle. In each
plantation a minimum of one 2m square wire exclosure (to keep out rabbits) and one unenclosed
square (for comparison) were identified. In total, 17 plots were sprayed off using ‘Roundup’
before later being raked to scarify the ground. All were marked on plans of the
In early October 2001 KCT staff collected 25 sacks of material, taken from
various sections of the track in the source woodland, to include a variety of habitat
types. The material was taken to Kemerton and within hours was spread thinly over the
trial plots and then raked over to incorporate it into the top 5cm. It was important
not to leave the damp material in the sacks for long to avoid overheating.
In addition to being marked on a plan, the position of the unenclosed plots was
also identified by marking the nearest tree to the southeast corner.
The plots were then monitored annually and any invading coarse vegetation
In 2004 a decision was made to build some larger exclosures – this time 10m x
2m. Six plots were identified – some alongside a permissive path so that the public
could follow the progress of the trial. The ground was sprayed off and then later
cultivated to a depth of 15 cm using a ‘walk-behind’ machine. Thin layers of Coile and
then wood chippings were worked in to provide an artificial loam layer. Any further
re-growth was sprayed off.
In October sixteen bags of material were collected from the source
woodland. This time no excavated spoil was available and so staff raked small areas,
collecting leaf litter and soil to about 5cm. Within hours the material was spread in 4
of the new exclosures - at the rate of 4 bags per plot – and raked in. Later that
winter the other two plots were planted up with material grown in the estate greenhouse – one
with Daffodil seed, the other with Bluebell bulbs.
In autumn 2005, 4 small ‘exclosures’ of 1m diameter were established in another
plantation – 3 planted with Bluebell bulbs and one with a mixture of Daffodil bulbs and
Monitoring of these additional plots has continued since their
establishment. Plant species appearing within the plots and occurring elsewhere in the
plantations could not be claimed with any certainty to have been brought in and so only
species new to the site were recorded.
A: For the 2m x 2m plots.
In February 2003 all plots were checked and it soon became apparent that
collecting source material from a range of sites was producing differing results. In
Smiths Plantation the two exclosures held nine seedlings of Bluebell and one of Lesser
Celandine whilst five unenclosed plots held one sedge sp. seedling and one unidentified
In Richards Wood the southern exclosure had 34 seedlings of Wood Spurge and
there were three grazed seedlings of the same species in an unenclosed plot. In the
northern exclosure two viola sp. seedlings were found with nothing in an adjacent unenclosed
In Cherry Orchard plantation the exclosure contained three Wood Sedge, eight
Wood Spurge, several Strawberry, and one Fern. The two unenclosed plots contained one
Wood Spurge and two Strawberry seedlings.
In North Wiseacre the exclosure held 26 Wood Spurge, one Sedge, several
Strawberry and one St John’s Wort sp seedling. One of the two open plots held one
In Spring 2004 the experiment in Smith’s Plantation was abandoned after
vandals destroyed the exclosures.
At Richards Wood, in the southern exclosure the Wood Spurge was dominant but 17
Bluebell and two Creeping Jenny seedlings had emerged. There were 20 Bluebell in the
unenclosed plot. The northern exclosure now had 50 Bluebell seedlings whilst two were
found in the unenclosed plot.
In Cherry Orchard there were eight Wood Spurge, 12 Bluebell, three Wood Sedge, a
Fern, and two Early Purple Orchid rosettes (the first record for this species on the
estate). In the unenclosed plot there were seedlings of 12 Bluebell, and one seedling
each of Wood Spurge, Enchanters Nightshade and a Primula sp.
In the North Wiseacre exclosure Wood Spurge was dominant but 15 Bluebell
seedlings were found, together with one St John’s Wort sp and one Wood Sedge. One of
the two unenclosed plots held two Bluebell seedlings.
In Spring 2005 the exclosures in Richards Wood were largely unchanged but
encroaching rough vegetation had covered the southern unenclosed plot whilst the northern
unenclosed retained two Bluebell.
In Cherry Orchard the situation was unchanged except that grass species had
In North Wiseacre two plants of Perforate St John’s Wort and two of Enchanter’s
In Spring 2006 the southern exclosure in Richards Wood held 17 Bluebell
and 16 were found in the unenclosed plot. The northern exclosure held 52 Bluebell and
one Sweet Violet with eight Bluebell in the unenclosed plot.
Cherry Orchard exclosure had remained constant – except for Early Purple
orchid. The single plant flowered but later lost the flowering head – thought to be to
deer reaching into the plot. In the unenclosed plot there were a few grazed
In North Wiseacre the situation was unchanged – except that two Bluebell
flowered but ---
In December 2006 numerous seedlings of Wood Spurge were found growing up
to three metres outside the exclosure.
In February 2007 no changes were recorded for the exclosures in Richards
Wood, Cherry Orchard and North Wiseacre.
B: For the 10m x 2m plots
In 2005 aside from a few Bluebell seedlings no new plant species were
found. The exclosure planted up with Bluebell bulbs contained large numbers but not in
flower. The Daffodils did not appear in the other planted exclosure.
In 2006 once again only Bluebell was recorded as having established as a
new species in the exclosures. In one, a plant of Devil’s Bit Scabious that had come in
with the leaf litter flowered. In the ‘Bluebell exclosure’ one or two plants flowered
and in the ‘Daffodil exclosure’ a few seedlings appeared.
In February 2007 Larger numbers of Bluebell were now growing in the leaf
litter exclosures. In the exclosure that had been planted up with Bluebell bulbs good numbers
of robust plants had emerged.
C: For the 1m dia. Plots
In 2006 large numbers of Bluebell grew in three cages whilst three
Daffodil seedlings came up in the fourth.
In February 2007 the Bluebells continued to thrive but no Daffodils
seedlings were visible.
Discussion and Conclusions
It is important to remember that the trials apply to specific
ages and design of plantations at Kemerton – and with a particular level of grazing
The method demonstrates a potential simple and economical way of introducing
native ground flora into planted woodland from a local ‘rich’ source. The trials
continue and once each exclosure type has been established for six years the netting will be
removed and the effects recorded.
Given that a wider range of species and higher numbers of plants occurred within
exclosures, it is clear that grazing greatly affects success – and indeed, is likely to
elsewhere. In addition, it might be that the attempts to replicate soil
conditions were inadequate, but these trials were limited to a practical rather than
scientific approach so no research was carried out. However, if this was indeed a
limiting factor then it too is likely to apply elsewhere.
At this stage of the trials the smaller 2m x 2m exclosures have been more
successful than the 10m x 2m plots but it is not clear why. The leaf litter for the
larger plots was taken from similar sites – albeit to a lesser depth – and at the same time
of year. It could be that taking more loam or topsoil with the leaf litter
improves conditions for the translocated seeds and bulbs. The 1m dia. plots planted up
with bulbs and seed also appear to be very successful but further monitoring will be required
to see if the plants spread out from there.
Given that species and plants struggled to establish under a tree canopy similar
to the source site it would seem unlikely that they would succeed in new or very young
plantations, where competition from other plants would be much greater – or in situations
where the canopy excluded more light.
Where grazing pressure is high it is likely that only ‘unpalatable’ species,
such as Bluebell, Daffodil and Wood Spurge would survive. Whether Wood Sedge fits that
category will become clear later in the trials. Therefore grazing – and possibly soil
conditions – are the limiting factors. Thus, we can assume that buying a standard
‘woodland seed mixture’ to sow into young plantations might prove to be a waste of time and
money. Therefore, it is probably better to wait until the plantation has formed a
canopy that limits the ground flora and then to spread leaf litter from a known, local source
into prepared plots. The most expensive (but nevertheless effective) way might be to
plant locally grown (and of local provenance!), seed or bulbs of unpalatable species into
A wider, more scientific research project might well confirm what these trials
suggest. Moreover, it could encompass plantation age/stage, soil type/condition and a
comparison of grazing pressure between plantations and between source sites - thus producing
results well beyond what has been possible at Kemerton.
Harry Green and Worcestershire Wildlife Trust for allowing collection of leaf
English Nature for supporting the trials via the Aggregates Levy Sustainability