Giant trees of Ho Chi Minh City

I was away in Ho Chi Minh City, Vietnam for a week to attend M’s wedding and also for a short holiday. This is my second time here after more than two years.

Here is an view of the city from the rooftop of my hotel room. Very cluttered, disorderly but that is what I love about this place. Singapore is too orderly that it is boring in comparison to this place. =.=

How about the city’s greenery?

I doubt tourist pay any attention to the roadside streets here. But I was already anticipating the large dipterocarp trees which I read about in Dr Francis Ng’s blog. He estimated the trees to be 80 to 100 years old and planted during the French colonial days!

Many parts of the city were lined with huge dipterocarp trees! For those who do not know what are dipterocarps, they are big forest trees belonging to the family Dipterocarpaceae and highly valued for their timber (commonly called meranti). Also characteristic of this family are their shuttle-cock like fruits that will spin in the air.

It was quite common to see trees with trunks of 1 or 2 metres in diameter and growing more than 20 metres tall.

Two of the most common species are probably Dipterocarpus alatus and Hopea odorata. Above is a D. alatus tree at the reunification palace.

We can’t have picked a better time to come as it was dry season now and it means masting time for the trees! Can you see the young brownish fruits?

It is pretty fascinating to see the road littered with the fruits!

Here is the close up of the D. alatus fruit.

Look at the crazy mass fruiting of Hopea odorata~

And also some fruits on the pathway.

While Vietnam have amazing big mature forest trees, they certainly does not have as much green spaces as Singapore. Every park here are greatly valued and visited by many people, even during the weekdays. For example, my Vietnamese friend told me that this dipterocarp filled park is frequented by university students.

The most common dipterocarp that is planted in Singapore is probably Hopea odorata, but they are all still very young in comparison to the ones here. It will be pretty exciting once they reach to the same height and girth as what we saw here in Ho Chi Minh and start fruiting.

Watch out for more posts of the vegetation in Vietnam~

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Related posts:

1) Some city biodiversity in Saigon
2) Tree climbers in Ho Chi Minh City

Know 10 Street Trees stamp

I just returned home and saw my prudential letter on my table (I wonder why they have to send so many). Besides that, I noticed that on the envelope, there were some stamps depicting common street trees which I found interesting.

A check at SingPost website showed that it had collaborated with NParks to let the public know more about our 10 most common street trees in Singapore. More information in the pdf here. For those who want the whole collection, it costs only S$2.60!

Ant predation on fig wasps

Today I accompanied CJ and KY to collect some figs for a study. Coming across another new fig species for me, Ficus benghalensis, we took a closer look at its bright orange figs.

 
There were lots of ants but I initially took little notice of them. But as more and more ants crawled around the fig, it dawned to me that the ants were emerging from the ostiole of the fig. CK said that they are probably predatory ants that feed on the fig wasps.

And indeed, I found one ant carrying a winged fig wasp (centre of the picture), a female, since the male fig wasps do not have wings. I also remembered reading from somewhere that male fig wasps, besides chewing a tunnel out of the fig, also act as sacrificial lambs to ants by emerging out first so as to protect their mates. Apparently it didn’t really work in this case since the opening of the figs are so big that the ants can freely walk in and out of them.

Tagged Myna feeding nectar

The Sea Apple (Syzygium grande) out my kitchen window has been flowering luxuriously  recently and I decided to get some photos of their pom pom-like flowers for my collection.

There were many little pollinators buzzing around the flowers.

 
A Javan Mynas (Acridotheres javanicus) flew in after I finished taking the pictures and it hopped around the tree putting its beak into the flowers. It was only later when I was processing my images that I realised that this bird was tagged (Look the the grey ring at its leg).

 
Another picture of the bird on the another nearby inflorescence.

At first I had thought that it was just feeding on the insects attracted to the flowers. But it should be instead feeding on the nectar since BESG blog had recorded this bird doing it before.

I wonder what research this bird was ringed for. Any ideas?

Creeping Fig

The creeping fig, Ficus pumila is a common exotic fig used to cover the surfaces of overhead bridges and other structures.

There are two forms of these fig, the creeping ones have small little leaves while the others that extend outwards have bigger leaves as shown in the picture above.

And they bear big pear shaped fig fruits or more famously known as 无花果. The proper name for them are called the syconia.

QY sliced up it up into half for us to see the anatomy inside. These syconia contain both male and female flowers. The red ones are the female flowers and the white ones at the tip of the fruit where an opening called ostium are the male flowers. It is said that there are about 1000 male and 6000 female flowers in each fruit!

Many figs including this have mutualistic relationships with agaonid fig wasps. The female will squeeze through the ostia and lay eggs in the female flowers and die inside the fruit. Upon hatching, the males will mate with the young females and chew an opening to the ostia for their mates to escape. In the process, the females have to pass through the male flowers whereby pollen will be stuck on them.

And thus the female fly off to look for fig fruit to repeat the cycle, also bringing the pollen to fertilise other fig trees. The males which are wingless, die after fulfilling their husbandly role.

Red Pineapple

These shrubs have been here decorating the "Bedok Reservoir Punggol" signboard for years opposite Hougang Mall but this is the first time I have seen it fruiting. It looked just like the pineapple that we eat but the reddish tint on its leaves and fruit doesn't seem to tally.

A check on 1001 Garden Plants in Singapore showed that this is the Red Pineapple, Ananas bracteatus, which is in the same genus as the commercial pineapple we eat, Ananas comosus. This plant also originates from Brazil and the fruit is also edible though it not as well developed. Because of the sharp spines on the leaves, they are sometimes grown as hedges for security.

Cannons at HDB?

Was walking around the neighborhood looking for a bicycle shop. Thinking of purchasing one even though my parents was violently against it, which I cant understand till now. haiz...

That aside, I came by this wayside tree and its large pink flowers caught my eye. They looked marvellous! And the interesting thing is that they sprout out all at the main trunk under the canopy, which makes the sight more amazing.

Consulted my Nparks 1001 garden plants guidebk and it turned out to be called the cannonball tree (Couroupita guianensis) introduced from tropical America. Interesting name right? But why is it called cannonball?

The fruits of this tree actually look like cannonball! Unfortunately, there wasnt any fruits there now for a sample picture but I remembered one of the nature blogs did showcased it. Anyone know where so I can link it?

Update >> Thanx to Samson for providing the pictures :) Look at those cannonballs! 

Pimples?

A few weeks back, on Dec 7, I took this picture on a roadside pongpong tree (Cerbera odollam). Looks pretty weird that the entire stretch of pongpong trees along the road had these bumps. I emailed prof Tan who helped me consult his friend at Nparks.

"Pimples on pongpong trunk"

Heres the reply; apparently its nothing to be a cause for concern and no definite answers for its appearance.

"Such structures are not limited to Cerbera odollam. You can see them on Samanea saman (rain tree), Swietenia macrophylla and quite a few of our common roadside trees. From experience, they are often associated with epicormic growth (mainly, they are points where water shoots proliferate). I suspect that they may be just "callus like" tissues which have not decide what they should be, probably due to hormonal imbalances?"

"We do know they are not indicators of internal rot or other structural inadequacies or anomalies. They also do not appear to give any added information on possible adverse tree health and is unlikely the result of pest attacks. As such, we have not dedicate much effort to elucidate the reasons behind the structure."