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.

Moving trees

On 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.

Merton 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?'

All-purpose logs

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 Park.'

Good tree care in Merton's Parks

Trees, particularly 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, hairy, caterpillars 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 winter months.'

"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.

Contact us

London Borough of Merton
8th Floor
Merton Civic Centre
London Road

Telephone: 020 8545 3659