The Arboricultural team based in our Greenspaces team work on
various projects across the borough, maintaining trees and working in partnership with community groups
and charities to plant new trees.
occasion it is necessary to move trees. Its not something we
want to do. It's not a fashionable way of creating instant landscape. We do it only to save a tree from
inevitable planned destruction. Almost the only occasion for this will be when sites are developed.
This recent example took place in Durnsford Recreation Ground
as an expansion of a local school into the park took place and a vigorous young Mulberry, sponsored
some years ago by residents, lay directly in the path of the development.
Greenspaces Arboriculture ensured that the biggest possible
tree spade was used to lift the tree with the maximum possible volume of roots and relocated it at a
safe point in the park.
Its future is not guaranteed but the alternative was certain destruction.
You might ask 'was it worth it?' Our answer is 'why should we accept the destruction of a public asset
when the developer should pay for its protection?'
Merton's Greenspaces Arboricultural Team don't waste anything.
Big logs are Carbon Sinks, they are habitat for fungi and invertebrates as they very slowly decay, and
as a result a larder for birds. We make even more out of them as well. Barriers are needed in
many places these days to prevent the compaction and damage caused by car parking, flytipping and unauthorised
entry. They even (but not in this case) act as seating or informal play equipment.
In this series we can see the vital Greenspaces Transport Team
of Chris Ziajka and Bob Steers handling big oak logs as if they were feathers to protect the Senior
Oak at Cottenham Park in West Wimbledon. Merton Arboriculture has valued this tree at £154,000 so its
vital to protect it. Eighty metres of protective posts could cost as much as £8000. This operation will
be completed for less than £1200.
Swamp cypress (Taxodium distichum) has 'pneumatophores'
These are structures that are extensions of roots, which in the
tree's native habitat, rise above the water level in the Everglades and are believed to aid in getting
air to the submerged root system. The Parks Liaison Officers have had a redundant section of path removed
so that these can extend and grow freely around the trees and improve the health of these trees in Ravensbury
Good tree care in Merton's Parks
young ones, can benefit
greatly from an area
around them free of competition for water. It can be an area laid to mulch. Areas kept weed free with
chemicals are less welcome as there is always a risk of damage to the tree.
Here we can see the best way - a circle of soil turned over and
aerated by hand - in a Mitcham Park. Any rainfall running down the trunk, goes straight back to the
tree, mowers have no encouragement to go close and, perhaps most importantly, the message goes out to
the public that we value, notice and care for our trees.'
You may have seen a photo of this in your local paper - accompanied
by some scaremongering nonsense about 'invasions' and 'keeping windows closed', because the caterpillars
could 'cause irritation to skin, eyes, and throat'.
Relax, though there are some web -forming,
which are a problem, its not these. This one is Yponomeuta
cagnagella, the Spindle Ermine Moth caterpillar,
perfectly harmless and a fine food supply for birds. If there is one word to describe this phenomenon
its the word ' Wildlife!'.
Unfortunately lack of professionalism in this
case led to not
only the scare described above but also the pointless destruction of this colony by a commercial 'pest
control' company - NOT we hasten to add, by the London
Borough of Merton which ensures it has correct
information before applying chemical extermination method.
For gardeners we add that this insect defoliates Euonymus shrubs
and then the few survivors disperse. An area of these shrubs defoliated last year are once again in
fine health with just a handful of caterpillars present this year.
Spring is here
'Prunus 'Kanzan' - one of the most popular Japanese Flowering
Cherries, in a Mitcham Park.
Even after the flower begins to drop the tree will continue to
provide its beauty for a while in the form of a carpet of drifting fallen petals. Don't sweep them up,
they will shrivel and disperse on their own.
P. 'Kanzan' may have a set of problems in some locations but its
popularity is undiminished, probably because it signals the coming of spring and summer after the dismal
"Paulownia tomentosa - Foxglove tree - in one of Merton's
lesser known parks, London Road Playing Fields, which was transformed from a rather boring flat expanse
by the Greenspaces Team some years ago.
It now has play areas, meadows and wooded areas, a tree avenue
and many fine specimen trees, such as this one."
Trees in the snow
What's going on here? Proof of the way trees buffer climate -
whether we are talking about heat or cold.
The tree in leaf shelters the ground beneath (note that the trees
in the background without leaves or low branches have snow all round).
Perhaps snow melt from branches has dripped on the ground and
melted snow on the ground - unlikely because the effect occurs beyond the drip line. Whatever the mechanism
in action tree cover has resulted in the early disappearance of the snow - without the application of
expensive (and phyto-toxic) salt and grit!
Merton olive harvest
Merton’s Greenspaces (then Leisure Services) recognised as far back as the early
1990s that Climate Change, or Global Warming, as it was then referred to, would have an impact on the
variety of trees that would be suitable for the borough in the coming years, and began to source olives
and a number of other exotics, to cultivate.
There are now over 20 of these trees in various parks in Wimbledon and Mitcham.
They are hardy and, so far, pest and disease-free. The fruit crop is viable but the fruit are small
as changes in climate do not include any extension of day length which would allow the fruit to continue
growing after the summer months. This year the crop was fairly poor and, of course, never approaches
the quality or quantity of southern climes. The older trees and those places near one another are those
which fruit the best so don’t expect self sufficiency in olives from one in your garden.
Jackdaws at Canons
Is a huge congregation of jackdaws a ‘Parliament’, a ‘Murder’
or a ‘Murmuration’? The answer is a ‘Building’, believe it or not.
This occurred on Christmas day, with over 500 birds congregating on the Swamp Cypress
and an adjacent group of ashes at The Canons’ in Mitcham. Tawny Owls have also recently returned to
this site. Both birds favour big tall trees for their perching.
Pagoda at Canons
Tree wardens, Friends of the Canons' and Arboricultural staff cleared ivy from the
fine Pagoda tree in one of the Canons' Recreation Ground car parks.
Ivy does not normally strangle trees but if present in sufficient quantity and when
growing aggressively it can reduce the growth for the tree's own foliage, cover possible defects and
create weight imbalances. Removal must be timed so as not to disturb wildlife and avoid sudden exposure
of bark to extremes of temperature and sudden change.
Pagoda tree is the common name of Styphnolobium japonicum, more familiar from its
previous name Sophora japonica
Coming soon - son of Stumpy
This autumn is going to be a big year for nuts and berries
on many trees. Here are some of the bumper crop of acorns on Stumpy - the veteran Oak by Cannon Hill
lake which was given some artificial supports last year. Acorns will be collected later in the year
to grow a crop of oaks from a proven vigorous local provenance.
Tetradium at Canons
The issue of 'fighting' dogs
being trained by their owners to attack trees is a growing national problem. Large trees worth many
thousands of pounds have been damaged and killed.
This tree was a Tetradium danniellii (Euodia), an expensive
rarity planted in the Mitcham Arboretum. After one year of excellent progress in establishment it was
attacked. Arboricultural staff subsequently installed a bark graft in an attempt to maintain the transport
of nutrients and water through the tree and placed a notice on it to let the public know what had happened.
The graft - which is difficult and not always successful in such circumstances - failed after a period
of success but will be tried again in a last ditch effort to save the tree.
Plane tree pollards
For our changing climate, for shade, carbon sequestration and temporary interception
of particulate pollution, big trees are best. The London Plane (Platanus x hispanica)
is well known from the Parks and Squares of London and has tolerated the pollution in the city's
atmosphere. It also tolerates heavy pruning - where space and other limitations demand, the tree can
be drastically reduced in size. One of these Planes was pollarded in 2008/9, the other two years ago,
so we can see the speed at which they can recover from pruning and regrow.
If we remove a tree for any 'cultural' reason- i.e. because its 'too big' or causing
some perceived nuisance, replacement is a long and doubtful procedure; a young tree is at risk for years
before it is sturdy enough to face city life. Trees like Planes which can be pruned but are not so vulnerable
to damage, vandalism or abuse, are the best ecological assets we can have in our streets.
Poplar in Morden Park
Dismantling a large Populus serotina (Hybrid Black Poplar) in
Morden Park, early summer 2009. These trees can be huge and have often been pollarded in the past, leading
to decay and cavities high above the ground. This can be potentially hazardous but gives wide opportunities
for wildlife habitats, from bird nesting to bat roosts. This tree was retained as a six metre 'monolith',
with every section lowered by crane and examined for the presence of bats. None were present.
London Borough of Merton
Merton Civic Centre
Telephone: 020 8545 3659