With over 2 million trees in Singapore, there are massive variances in maintenance standards between trees.
A commonly seen example of bad pruning is “topping”. This practice chops large branches back to a pre-determined limit, into stubs without sufficiently large leaf-bearing branches (also known as a “terminal leader”) nearby. Some trees decline and eventually die because of periodic topping.
Topping is a temporary solution at the expense of overall tree health. Other more sustainable solutions, like thinning and size reduction, could have been implemented with the same resources.
Here is a Syzygium grande that has been repeatedly topped for “safety purposes”. This species has been criticized for its weak branches, but one cannot help but question if bad pruning practices have led to its poor reputation.
Notice how branches end abruptly. The tree’s natural shape is destroyed, while the topped branches try to put out new leaves to replace lost foliage, giving the tree spots of bushy growth.
Leaves are the photosynthetic factories of a tree; no leaves = no food to support living cells.
Tree longevity should always be kept in mind when pruning. Done by a skilled operator, pruning can improve the overall structure, stability, and health of the tree. Done poorly, higher maintenance costs and hazards from unstable sprout production are likely.
This Alstonia angustiloba below displays good previous pruning.
It has grown short, fat, and dense. Unlike a topped tree, constant maintenance isn’t necessary, its natural shape is retained, and is unlikely to be a public risk.
Plenty of Singaporean trees are topped as a management strategy. With the exception of a few extraordinary circumstances, topping does more harm than good.
We need to understand that while topping might be the easiest solution, it isn’t a sustainable one.
Maintenance frequency for a topped tree (to remove new weakly attached shoots) can run up to once every 3 months. In contrast, a well-managed tree can go for 3 or more years without attention.
For trees in private estates, hiring competent people for tree management is key. Whereas for public trees, signs of poor tree management can be reported to the relevant authorities via https://www.oneservice.sg/.
Glance out the window in Singapore and it’s likely something will be waving back at you. It might be smooth or scaly, bigger than a bus or small enough to push over.
We live in a literal urban jungle, with trees peeping from around buildings, lining the sidewalk, or dominating plazas and courtyards.
“There is little in the architecture of a city that is more beautifully designed than a tree.” – Jaime Lerner
How do Singaporeans co-exist with our big mature trees?
Part of the answer is that our estate managers and urban planners work hard every day with architects, landscapers and arborists; trying to balance developmental needs with liveability and public safety.
Trees are an arborist’s speciality. We combine scientific knowledge with skill and experience to diagnose potential problems, and prescribe treatments for holistic management of trees.
Based on experience, frequently overlooked parts of tree care include:
Contract Specification Planning:
Long-term preservation of trees begins before contracts are signed: draft clear directions on proper tree care. Consult an arborist on potential tree-related loopholes in contracts.
Engage your arborist to prune young trees and develop strong form. Young trees pruned into biologically efficient forms minimize the potential for future structural problems and liability for tree owners.
Optimal pruning techniques? Tree work safety? Work teams often get a productivity boost through specialist training.
Long, useful, and safe life expectancies for urban trees require proper planning and sustained effort. Other areas where an arborist can help include biology-first design, stock selection, installation and establishment methods, mature tree tune-ups, and risk management.
Running into an unfamiliar species is always an interesting experience, identification can be challenging, with plenty of trial and error. Even with the power of the internet behind you, information can be limited and frustration is common.
However, when you finally get that “Eureka!” moment and find a match, what follows is a rush of adrenaline and an excited flurry of research. In the meantime, having a distinctive species smugly sit in front of you while being unable to identify it is hair-tearing.
Never has this experience been more pronounced when I was faced by this species at Bukit Brown Cemetery.
I felt stupid for the longest time when I could not figure out the name of such a distinctive plant with its absurdly large tri-lobed leaves. The specimen shown above is a small one. Mature individuals in the cemetery reach about 15m high.
Big leaves. Colleague for scale.
It was only when I ran into its cousin the Common Mahang (Macaranga bancana) that something clicked. This is the Giant Mahang (Macaranga gigantea). While the leaves are similar in shape to the Common Mahang, they are much larger, and its twigs do not contain mutualistic ants like its Common cousin.
Its role as a pioneer species fit the Bukit Brown Cemetery perfectly. Closed to new burials in 1973, secondary rainforest has been slowly reclaiming much of the area. Large tracts of open disturbed land? Perfect for the Giant Mahang.
Given enough time, these trees are eventually overtaken by larger, shade-tolerant competitors. However, the copious amounts of small fruit that it produces while it is alive ensures dispersal by animals to other open areas.
16 June 1963, Mr Lee Kuan Yew plants a Mempat tree (Cratoxylum formosum) at Farrer Circus, launching an island-wide greening movement that has continued for more than five decades.
Image Source: http://www.asiaone.com/singapore/trail-mr-lees-trees
As a testament to the pace of redevelopment in Singapore, of the more than 60 trees planted by Mr.Lee since 1963, 39 have survived while the rest (including that first Mempat tree) no longer exist.
Heritage trees are individual or groups of trees that are so special that they are worthy of recognition and protection for future generations. These trees broadly fit into three main groups; visual importance, scientific value and cultural connections.
Announced on 17 August 2001, the heritage tree program by NParks recognizes exceptional mature trees worthy of conservation. As of November 2017, there are 265 heritage trees in the register.
Read more here: https://www.nparks.gov.sg/gardens-parks-and-nature/heritage-trees
How do myths perpetuate? Are they based on loose truths – or can they be unfounded and harmful? Here are 5 common tree care myths:
Myth 1. Trees planted deep = strong deep roots.
You can’t see root flares when trees are planted too deep. Trees should be planted with root flares above the soil line. The root flare is adapted to be dry and free of soil – if buried in the soil and constantly moist, root flares are susceptible to disease and a source of stress for trees.
Myth 2. Trees require lots of water
Trees need water, but probably not as much as you think. It is easy to drown trees, especially saplings. Mouldy flowers, new and old leaves falling at the same time; are signs of overwatering.
Myth 3. More mulch will benefit trees.
Overmulching or volcano mulching, buries a trees root flare and can disrupt soil moisture and aeration. It’s suggested to apply small amounts over time, narrowing the depth of the mulch as it gets close to the tree trunk.
Myth 4. All insects and fungi that live on trees are harmful.
The vast majority of insects and fungi living on trees are not harmful to tree health. Insects help in pollination, fungi can capture water and nutrients; making more resrouces avaialble to tree roots.
Myth 5. Pollarding and topping are the same thing.
Pollarding is done intentionally, usually for aesthetics; it’s planned and executed on schedule, beginning while trees are young.
Topping is indiscriminate, with large mature trees cut down to an imaginary line without regard to tree biology. This can lead to a shortened lifespan. The shoots produced in response to topping cuts are often weakly attached and break off as they grow larger.
Property owners in Singapore often require professional recommendations on tree risk and health. Arborists sometimes prescribe conservative recommendations because risk-adverse property owners appreciate new buildings; concrete and metal rather than trees.
Arborists are translators, communicating a tree’s messages to humans. But there is great pressure to fall in line with the property owner’s expectations and dispose of liability. Risk can never be reduced to zero while retaining a tree’s benefits. Like a medical doctor faced with a litigious patient and their family, an arborist will recommend the most conservative solutions of expensive surgery or removal.
These trees have been standing for many decades, providing shade, improving the air, supporting the ecosystem, silently working 24 hours a day for our benefit. All they require is regular attention every few months.
Having low risk, well-managed trees in an estate costs very little. Expensive surgery only results from old, sick trees that were poorly maintained, made worse by a property owner’s risk adverse attitude.
Here lies my love for trees, I found this poem in an old book:
The Tree’s Prayer
You who would pass by and raise your hand against me
listen before you harm me.
I am the heat of your hearth on the cold winter nights,
the friendly shade screening you from the summer sun;
And my fruits are refreshing draughts
quenching your thirst as you journey on.
I am the beam that holds your house,
the board of your table,
the bed on which you lie
and the timber that build your boat.
I am the handle of your hoe
and the door of your homestead,
the wood of your cradle
and the shell of your coffin.
I am the gift of God
and the friend of man.
You who pass by, listen to my prayer…
Harm me not.
-Translated from “Ao Viandante”, Veiga Simões, May 1914.
Do we need a Landscape Designer?
Landscape design is sometimes overlooked when building or renovating an estate. Here are several reasons why that may be the case.
Not in “To-Do-List”.
When renovating a new house, landscaping is often the last item on an owner’s “To-Do-List” despite being the first thing visitors encounter.
There is no need to hire Designers, “Anybody” can do it.
Perhaps the owner is accustomed to doing their own gardening. They feel confident in designing their landscape from scratch. However, it is still prudent to seek professional advice. Proper planning, preparation and installation is very important for landscape to thrive and remain beautiful for many years.
A low bid is a good bid.
Owners choosing the cheapest landscape contractor is closely tied to landscaping being on the back of their minds when renovating a house. Contractor reputation, past projects and materials chosen are good gauges and should not be ignored in favour of price.
Plants? Choose the cheapest.
Nothing beats good research. What may seem like a shrub can turn into a tree in 3 to 5 years, obscuring the view from a house. Cheap purchases might also cost more in future maintenance. A landscape designer can offer professional help in deciding which plants will be a sound investment for the future.
Just planted a new tree?
It may be small now, but with a basic understanding of tree biology, you can help it grow to its full potential.
Here are three simple tasks:
1.Stake the tree, only if necessary.
Studies show trees establish more quickly and develop stronger trunk and root systems if they are not staked at the time of planting. Staking may be required when planting bare root stock or planting on windy sites. Materials should be flexible and padded to minimize injury to the trunk, yet still allow movement. It is important to remove support staking and ties after the first year of growth.
2.Mulch the base of the tree.
Mulches spread around the base of a tree, holds moisture, moderates soil temperature extremes, and reduces grass and weed competition. The two major types of mulch are organic and inorganic. Inorganic mulches include various types of stone, lava rock, pulverized rubber, geotextile fabrics, and other materials. Inorganic mulches do not decompose and do not need to be replenished often. On the other hand, they do not improve soil structure, add organic materials, or provide nutrients. A 2- to 4-inch (5- to 10-cm) layer is ideal. More than 4 inches (10 cm) may cause a problem with oxygen and moisture levels. Piling mulch right up against the trunk of a tree may cause decay of the living bark.
3.Limit your pruning.
At the time of planting, limit pruning to dead or broken branches. All other pruning should be withheld until the second or third year, when a tree has recovered from the stress of transplanting. You should always have a distinct purpose in mind before making any pruning cut; every cut has the potential to change the growth of the tree.
Note: This post shares content from http://www.treesaregood.org.
Please visit the site for more excellent tree care information!
The International Society of Arboriculture (ISA) divides tree risk assessment into three levels.
Level 1: Limited Visual Assessment (eyes only inspection, on foot, drive-by etc)
Level 2: Basic Assessment (ground level inspection with simple hand tools)
Level 3: Advanced Assessment (climbing may be involved along with diagnostic equipment.)
These are often modified to collect additional data that clients deem important and within available timeframe and resources.
For example, in a large estate with thousands of trees, trees situated away from human habitation may get a Level 1 assessment, while trees close to road junctions or of a certain girth size receive Level 2 or 3 assessments on a more frequent basis.
Evaluating Tree Risk:
Tree Risk is evaluated in the following way,
Risk rating matrix
The risk rating gives a good gauge for prioritizing remedial actions. It is worth stressing that every part of the process, not just the final rating, is important. An insufficiently thorough assessment level cannot give enough information for a reliable risk rating, while an overly excessive assessment level wastes time and resources.
We hope that this gives the public a better idea of how tree risk is evaluated, this is but a brief explanation of the risk assessment process. Full tree risk assessment courses and manuals should be available from the Centre for Urban Greenery and Ecology (CUGE).
Some of the largest trees in Singapore are from the genus Ficus (fig trees). How did they become so successful? Our Arborists takes a closer look at reproduction.
Long-lived as trees may be, death eventually comes for (almost) all living things. Just like us, trees have to reproduce for their species’ survival.
However, unlike us, trees stay rooted to one location for all their lives. They cannot seek out new areas for resources to sustain themselves. Should young trees grow too near their parent, both parent and offspring will compete for the same resources.
Seed dispersal is vital for ensuring young trees not only survive, but thrive wherever they may grow.
To this end, some trees have enlisted the help of animals in aiding seed dispersal. The animals are paid for their efforts, fleshy fruits feed and sustain animal populations. Such mutualisms are important in sustaining biodiversity.
Trees with fruits that appeal to animals have a better chance of survival; their fruits are selected by disperser animals and their seeds spread far and wide. Their offspring with attractive fruits will in turn pass on their attractive fruit traits to subsequent generations.
Through natural selection and many generations, different but related species of trees may form with different fruits based on which animals they attract.
Bat or Bird?
Research has compared figs that are dispersed by bats and figs that are dispersed by birds, showing how these different figs have evolved to fit dispersal by birds or bats.
Removing all live foliage is NOT a good idea. Note the leaves on the lorry and not on the tree.
You may have noticed that areas with poorly maintained trees get hotter.
This is no coincidence, a recent study published in the Proceedings of the National Academy of Sciences (PNAS) reports that tree cover can affect temperatures by up to 5.7°C (Ziter, 2019). It is the difference between being in the tropical heat at 30°C and in an air-conditioned room at 24 to 25°C.
What often happens is that tree owners disown liability and foist responsibility unto landscape contractors with fine print in poorly-worded contracts, assuming the hired contractors know what is best for their trees.
Do not assume landscape contractors know what is best for your trees.
Landscape contractors vary in tree maintenance knowledge breadth and depth. Anyone can start hacking away at a tree with a chainsaw, years of experience is not a good indication of tree maintenance knowledge. Contractors want repeat customers, they will do what they are told even if the tree owner suggests something wrong. Incompetent contractors will straight up offer solutions that harm trees.
Tree owners must have some basic knowledge so that they do not give their contractors incorrect instructions or accept their contractor’s offered solution at face value.
At the bare minimum, visit one of the trees with the contractor and ascertain where they will cut. Agree on how much foliage is to be removed before work (anything more than 30% is usually too much).
Under no circumstances should a contractor be allowed to top/head/hat-rack/pollard a tree in Singapore, harming trees by leaving behind ugly bare stubs.
When faced with evidence that the hired landscape contractors are damaging their property, irresponsible tree owners shy away from further corrective action on their part as long as their proverbial behinds are covered by their maintenance contracts.
If you, or someone you know, are in-charge of trees in or near public spaces, we would like to take the opportunity to beseech you to take responsibility for the plants in your care. Educate yourselves on proper tree maintenance. Do not assume landscape contractors know what is best for your trees. And definitely do not use maintenance contracts as a way to shift responsibility to the contractor.
If you’re a member of the public and see disfigured trees near your homes, do not stay silent. The trees may have been contributing to a cool and pleasant environment for decades. A spike in your electricity bill from increased fan and air-conditioning use can be an indirect result of tree neglect.
Ziter, C. D., Pendersen, E. J., Kucharik, C. J., Turner, M. G. (2019). Scale-dependent interactions between canopy cover and impervious surfaces reduce daytime urban heat during summer. Proceedings of the National Academy of Sciences of the United States of America, 116(15), 7575-7580.