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.
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.
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!