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Bisham Woods – 25th April 2010

Michael Keith-Lucas led a walk in Bisham Woods on Sunday 25th April. The woods, which lie on a steep slope overlooking the River Thames near Marlow, are ancient mixed woodland with a rich ground flora. One of the local specialities is Small-leaved Lime, Tilia cordata, with characteristic soft, heart-shaped leaves. It took some time for the group to move off, because there were so many ancient woodland indicator species growing close to the car park. These included both Common and Early Dog-violet, Wood Anemone, Solomon’s Seal, Bluebell, Primrose, Wood Spurge and Enchanter’s Nightshade. The Dog’s Mercury plants in a sunny position at the side of the ride were all identified as males. The female plants prefer shadier conditions and were duly located later in a more suitable position.


Prompted by the sight of a beech seedling, Michael outlined some of the problems currently being faced by Chiltern beech trees. With milder winters, the trees are producing pollen at earlier dates, but a single degree of frost is sufficient to destroy a season’s pollen production. As a result, in 4 out of 5 years, no viable beech mast is produced. Beech seedlings need shade, and the best conditions for growing young beeches are with a conifer nurse crop. However, in some quarters, the planting of conifers is considered to be inappropriate for the Chilterns. The most suitable conditions for beeches are on the clay-with-flints, above the chalk. Many of the older beeches were planted on the less-suitable steep chalk slopes. Being a shallow-rooted species, they are particularly vulnerable to droughts or strong winds. Many beech trees in the steepest part of the wood were felled in the great storm of 1987. Large numbers of ash trees and a few larches have grown up in the area of storm damage.  


Michael pointed out that the woodland evergreens such as ivy, holly and yew are Atlantic species which decrease in abundance as one moves eastwards across Europe. Other ancient woodland indicator species encountered on the walk included Woodruff, Twayblade, the wasp-pollinated Common Figwort, Sanicle, Yellow Archangel, Wild Cherry and Common Whitebeam. Several Orange Ladybirds were seen. A round, smooth, dense pebble was identified as coming from the Bunter Beds in the Midlands.

Pictures by Rob Stallard and Jan Haseler

RDNHS Walk 25 April 2010 Bisham Wood

Fagus sylvatica   Beech
Fraxinus excelsior   Ash
Corylus avellana   Hazel
Mercurialis perennis   Dog’s-mercury
Polygonatum multiflorum   Solomon’s-seal
Hyacinthoides non-scripta   Bluebell
Arum maculatum   Lords-and-Ladies
Anemone nemorosa   Wood Anemone
Primula vulgaris   Primrose
Viola reichenbachiana   Early dog-violet
Euphorbia amygdaloides   Wood-spurge
Veronica montana   Wood Speedwell
Ajuga reptans   Bugle
Geum urbanum   Wood Avens
Circea lutetiana   Enchanter’s-nightshade
Lysimachia nemorum   Yellow Pimpernel
Melica uniflora   Wood Melick
Ranunculus ficaria   Lesser Celandine
Brachypodium sylvaticum   False-brome
Cerex remota   Remote sedge
Tilia cordata   Small-leaved Lime
Hypericum androsaemum   Tutsan
Ligustrum vulgare   Wild Privet
Geranium robertianum   Herb-Robert
Acer campestre   Field Maple
Cornus sanguinea   Dogwood
Hypericum hirsutum   Hairy St John’s-wort
Hypericum pulchrum   Slender St John’s-wort
Sanicula europaea   Sanicle
Listera ovata   Twayblade
Galium odoratum    Woodruff
Hedera helix   Ivy
Ilex aquifolium   Holly
Taxus baccata   Yew
Sorbus aria   Common Whitebeam
Ribes rubrum   Red Currant
Lamiastrum galeobdolo   Yellow Archangel

list compiled by Janet Welsh