Trees, Scrub and Hedgerow
Trees are found in many situations within the urban environment.
This action plan covers woodlands, parkland, wood pasture and
individual trees in streets and gardens. Deadwood habitats,
hedgerows, scrub and areas of natural regeneration are also
included. Trees play a vital role in the urban ecosystem, providing
local benefits for wildlife. Many birds, mammals and invertebrates
use trees as roosts, breeding sites and feeding areas.
Woodland
Woodland can be defined as vegetation dominated by trees more
than five metres high when mature, forming a distinct though
sometimes open canopy. Existing woodland, new plantations and
commercial plantations are all included in the plan.
Parkland and Woodpasture
Parkland and woodpasture are the products of historic land
management. They usually consist of large, open grown or high
forest trees (often pollards) at various densities. Most of the
trees are usually native, but there may be non-native species,
which have been planted or have grown naturally.
Roadside Trees
Trees and shrubs, in streets, recreation areas or private
gardens play an important part in making our urban area a more
pleasant place to live. They perform a number of functions:
reducing air and noise pollution, creating shade, softening the
built environment and creating local distinctiveness. In urban
areas, with few wooded habitats, roadside trees are especially
important for wildlife.
Deadwood
Deadwood is valuable for wildlife, providing a range of habitats
including dead limbs on living trees, decay columns in trunks and
branches, rot holes in standing trees and standing and fallen
deadwood. Deadwood habitats become available as homes for a variety
of invasive organisms such as bacteria, lichens and fungi. These
organisms make the habitat more easily accessible for other animals
for breeding or shelter. All trees, including ornamental trees, are
potential sources of deadwood, whether they are in woodlands, or as
single specimens in parks, gardens, hedgerows, or avenues in towns
and cities.
Scrub
Scrub can be defined as vegetation made up of either native or
non-native shrubs and tree saplings ranging from scattered bushes
to closed canopy vegetation, usually less than five metres tall,
occasionally with a few scattered trees. Scrub is often a stage in
the natural succession to woodland. The value of scrub for wildlife
depends on the species present and their age range, therefore it
varies over time.
Hedgerows
Hedgerows resemble woodland edge and scrub habitats; they are
important habitats for butterflies and moths, farmland birds, bats
and other mammals. Hedgerows may also act as wildlife corridors for
many species, including reptiles and amphibians, allowing their
spread and movement between other habitats.
Current Status
The total area of woodland of 0.1 hectares and over in England
is 1,097,000 hectares, representing 8.4% of the land area.
Fifty-four percent of all woodland is broadleaved. Conifer woodland
represents 26%, mixed woodland 12% and open space within woodland
6%. There was a significant increase in woodland cover during the
second half of the twentieth century. It is estimated that there is
about 450,000 km of hedgerow in the UK.
A recent 10-year survey by the Forestry Commission has shown
that Hull and Humberside have the lowest tree cover in England.
Since 1991 the cover has increased in other parts of Yorkshire but
the East Riding area has stayed static and therefore fallen
behind.
Within Hull there are examples of several wooded habitats.
However all examples are small and none of them is completely
natural. Most of the patches of mature trees are very open with
little under-storey and therefore not attractive to all woodland
species.
There are several woodlands in Hull. Ings Plantation at
Kingswood, which is made up of a mixture of Ash (Fraxinus spp.) and
oak (Quercus spp.), and Ash Plantation at Bransholme are
particularly important to the City's wildlife. Birch Plantation in
Priory Yard East is made up of Birch (Betula spp.) and Willow
(Salix spp.) and is one of the few naturally regenerated woodlands
in the City. Disused railway sidings provide excellent examples of
scrub habitats within Hull. 'The Lozenge' is a particularly good
example of this. Tree-lined areas such as the Avenues, Newland Park
and Salthouse Road provide a substantial number of mature trees and
shrubs. Mature ash, oak and beech provide roosting holes for bat
species, especially the highly tree hole dependent Noctule bat
(Nyctalus noctula).
The City Ecological Survey in 1992 included 28 km of hedgerow,
of which 95% were unmanaged and may therefore have deteriorated as
both wildlife habitat and landscape features.
Current Factors Affecting the Habitat
- Urban expectations of tidiness (e.g. mowing, removal of fallen
leaves and dead wood) often reduce the natural biodiversity.
- There are often conflicting pressures for land use, for example
development, and consequent loss of habitat.
- Dutch Elm disease had significant adverse effect on the Elm
population in Hull. Many of the avenues of Hull were once lined
with Elms, nearly all of which have been lost.
- Vandalism is a constant issue in urban woodlands, usually
through firestarting; the uprooting of newly planted trees, dumping
and litter accumulation.
- Isolation and fragmentation of woodlands has resulted in poor
dispersal of dependent species.
- Invasion of non-native species such as Rhododendron, Giant
Hogweed, Japanese Knotweed and to a lesser extent Sycamore have
reduced the diversity of many woodlands.
- Woodlands may be perceived as threatening places and may give
cover for antisocial behaviour and crime.
- In some woodland there is a lack of younger generations of
trees producing a skewed age structure.
- Neglect and loss of expertise of traditional tree management
techniques (e.g. pollarding), leading to trees collapsing or being
felled for safety reasons.
- There are conflicts between roadside trees and the foundations
of older houses; this problem is especially prevalent in Hull
because of the high clay content of the soil. There is pressure to
lop or remove trees to avoid or reduce structural subsidence. This
leads to a significant level of damage to the urban tree
stock.
- Damage to roadside tree roots from soil compaction and erosion
can be caused by people walking and car parking.
- The digging of trenches close to trees can cause root damage
and reduce their safe useful life expectancy, leading to their
early removal. Principal causes of this type of root damage occur
during the installation and maintenance of cable TV, IT networks
and of statutory services (e.g. water, gas, electricity and
sewerage). The construction and improvement of highways can also be
locally significant.
- If scrub is left unmanaged it will eventually turn into
woodland and the important habitat that scrub provides will be
lost.
- Neglect or poor management of hedgerows, (no cutting or laying)
leads to them changing into lines of trees and the development of
gaps.
Current Action
Legal Status
There is a wide range of statutory acts (namely the Town and
Country Planning Act (1990) and Wildlife and Countryside Act
(1981)) and local by-laws that impose a duty on local authorities
and the general public to protect certain trees, habitats and the
species that use them. These are supported by guidance from
government, government agencies and non-government organisations in
the form of circulars, advisory and practice notes.
Management, Research and Guidance
The UK Biodiversity Steering Group has published a Habitat
Action Plan for Lowland wood-pasture and parkland. The objectives
and targets for this habitat cover conservation, restoration and
expansion. The national target is to protect and maintain the
current extent and distribution of lowland wood-pasture and
parkland in favourable ecological condition.
There is a wealth of management advice available with some
opportunities for grant aid. The Forestry Commission administers
the Woodland Grant Scheme (WGS), which provides grants for planting
trees and managing woodlands. They also publish a large range of
free and priced literature, from basic information leaflets to
detailed technical handbooks, on forestry subjects. The Forestry
Commission's 'National Inventory of Woodland and Trees in England'
was completed in 2000. The inventory provides information on the
extent, distribution and composition of woodland in the whole of
the country.
National Tree Week is organised annually, usually in
November/December, by the Tree Council to celebrate the start of
the tree planting season, and to raise awareness of the importance
of trees and their good management.
British Lichenological Society has produced a habitat management
guide for lichens, including wood-pastures and parkland.
KuHCC Urban Forestry Department maintains trees within Hull
where necessary, and carries out new planting schemes. They are
also responsible for emergency tree works i.e. storm and gale
damage. KuHCC Grounds Maintenance are responsible for maintaining
hedges within the City. Privet hedges within our parks are cut
three times per year, as are hedges belonging to selected council
houses. General Privet hedges are cut twice a year and Thorn/Beech
hedge is cut once per year.
Action Plan Aims
- To protect and maintain the current extent and distribution of
trees, scrub and hedgerows within the City.
- To make greater use of native species where
appropriate.
- To encourage planting of native trees and shrubs, especially
those of local provenance.
- To ensure that scrub habitats are well-represented across Hull
and within a range of habitats, and prevent loss of scrub habitats
that support sensitive species or suites of species, particularly
where scrub forms a mosaic with other habitats.
- To increase the amount of deadwood within the City.
- To improve hedgerow management.
- To monitor the bird species in trees, scrub and
hedgerows.
- To increase public awareness of trees and tree planting within
the City.
What We are Going to Do
Action
|
Target
|
Partner
|
Aim
|
|
Policy and Legislation
|
| No policy or legislation proposed. |
|
|
|
|
Habitat Management and Protection
|
| Increase the amount of deadwood habitat. |
Ongoing: Where possible allow trees and parts of trees to
mature, die, fall and decay naturally without interference.
Ongoing: Crowns of trees only removed where necessary. |
KuHCC (Parks and Open Spaces) |
5 |
| Ensure that scrub is well-represented across Hull and within a
range of habitats. |
Ongoing: Identify important scrub areas and carry out
management to stop valuable scrub habitats turning to
woodland. |
KuHCC (Parks and Open Spaces) |
1,3 |
| Plant hedges in suitable habitats. |
Ongoing: Planting of hedgerows around parks, golf courses and
cemeteries where appropriate. |
KuHCC (Parks and Open Spaces) |
1,2,3 |
| Improve hedgerow management |
Ongoing: Manage hedges on a rotational basis so that each is
cut only once every 3 years. |
KuHCC (Grounds Maintenance) |
6 |
| Encourage use of local provenance trees. |
Medium Term: Establish nursery for local provenance trees. |
BGEEP, YWT |
2,3 |
| Improve understorey. |
Medium Term: Understorey improvements to existing woodland
areas through introducing suitable native species. |
KuHCC (Parks and Open Spaces) |
3 |
| Improve links between woodland sites. |
Ongoing: Plan plantings to create links across the City. |
KuHCC (Parks and Open Spaces, Highways, Planning) |
3 |
|
Advisory
|
| Promote planting of native trees and shrubs. |
Short Term: Promote planting of Buckthorn to provide larval
food source for Brimstone Butterfly.
Medium Term: Produce information leaflet for garden centres on
native trees and shrubs people should plant in their gardens for
wildlife. |
YBC
KuHCC (LA21, Planning), University of Hull, YWT. |
2,3 |
|
Future Research and Monitoring
|
| Monitor birds in trees, scrub and hedgerows. |
Ongoing: Monitor bird species. |
HVWG, EYB |
7 |
|
Communications and Publicity
|
| Education and promotion of 'A Greener City'. |
Short Term: Events, public consultation, flagship projects and
publicity. |
KuHCC (All), YWT |
8 |
| Increase awareness of 'Trees for Babies' scheme. |
Ongoing: Promote 'Trees for Babies' scheme. |
KuHCC (Parks and Open Spaces, Registry Office) |
8 |
What We Can All Do
Plant native trees and shrubs, preferably using plants of local
origin.
Leave deadwood to decay naturally.
Carry out hedge maintenance in late winter (December-February) so
that nesting birds are not disturbed and flowers and fruit are
produced.
Links With Other Action Plans
This Habitat Action Plan should be considered with those for
Gardens and Allotments, and Parks, Golf Courses and Cemeteries.
Elms were once common on the tree-lined avenues of Hull but are now
very rare in the City. Lichens occur on many trees. Open woodland
is the preferred habitat of the Spotted Flycatcher. Woodland edge
and hedgerows are important habitats for the Tree Sparrow,
Hedgehog, Common Lizard, Great Crested Newt and Common Toad. Reed
Buntings also often use hedgerows in the winter. Buckthorn growing
in hedgerows is essential for the survival of the Brimstone
Butterfly. Scrub habitat is particularly important for the
Linnet.
References
Carr, S., Nell, M. (1991) Practical Conservation. Boundary
Habitats. Open University and Nature Conservancy Council, Hodder
& Stoughton, London.
Fuller, R.J., Peterken, G.F. (1995) Woodland and Scrub. In:
Managing Habitats for Conservation, ed.
Sutherland, W.J. & Hill, D.A. 327-361. Cambridge University
Press, Cambridge.
Hodge, S. J. (1995) Forestry Commission Handbook 11: Creating
and Managing Woodlands around Towns. HMSO, London.
Kirby, K.J., Drake, C.M. (1993) Dead Wood Matters: The Ecology
and Conservation of Saproxylic Invertebrates in Britain. English
Nature Science 7. English Nature, Peterborough.
UK Biodiversity Steering Group (1995) Biodiversity: The Steering
Group Report. Volume 2: Action Plans. HMSO, London.