The 2003 AGM address. Veteran trees and saproxylic invertebrates at Hylands Park
Site Register. Later developments included the Index of Ecological Continuity and the Saproxylic
Quality Index, which used the rarity status of species recorded to achieve a figure which could then
be used to place a particular site in a ranked order.
The European Context
In 1989 the Council of Europe published a report Saproxylic Invertebrates and their Conservation
by Dr Martin Speight. In this report, Speight attempted to evaluate the conservation significance of
European wood-pasture/old forest sites using saproxylic invertebrates as bio-indicators of habitat
quality. His list of indicator species, which he thought could be useful in identifying sites of
international importance, included the following four species:
Ischnomera cyanea (Coleoptera : Oedemeridae)
Callicera aurata (Diptera ; Syrphidae)
Callicera spinolae (Diptera : Syrphidae)
Psilota anthracina (Diptera : Syrphidae)
These four species have all been recorded at Hylands Park in the last two years, all four being
noted from the formal gardens area.
Trees at Hylands
Hylands has a great diversity of both native and planted trees. As a later landscaped park, the
treescape is dominated by standard trees (not pollards): some - particularly the oaks - are now of
an impressive size. The park also has a few pollards, coppice stools and bundle-plantings. The park
is also correspondingly rich in habitats for saproxylic species (dead-wood, sap-runs, rot-holes,
fungi, etc.). Of note is the large amount of dead-wood to be found about the park.
Another important factors for trees is that the ground around the trees is not ploughed (although the
northern part of the park around Swan Pond was cultivated until the 1990s), which means there is
no disturbance to the root-plates of the trees. Also, there is no application of herbicide, fungicide,
or insecticide in the vicinity of the trees - important for invertebrates and particularly for the
fungus species that inhabit the root-zones of the trees. As a result of this, despite the ageing population
of standard oaks, the trees at Hylands are actually in generally very good health.
Another factor for trees at Hylands is that there is no Bracken Pteridium aqulinum invasion, unlike
some very acid wood-pasture sites, such as Epping Forest, the New Forest, or Moccas Park in
Herefordshire, where is has become an invasive pest species which, when dry, becomes flammable
and can damage some older trees. Some parks and forests have had tree regeneration significantly
checked by periods of heavy grazing by domestic stock or deer. Hylands has been grazed by domestic
stock, chiefly cattle and sheep, but also horses and is currently grazed and browsed by a herd of
around a hundred Fallow Deer and some Muntjac, but not enough to check regeneration - some
palatable species, such as Ash, surviving well. There is also no evidence of a browse-line which
characterises many over-grazed wood-pasture sites.
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Essex Naturalist (New Series) 20 (2003)