WHEN haze arrives in Malaysia, most of us know the routine.
We look out of the window and find the familiar hills swallowed by a grey curtain. Someone checks the Air Pollutant Index (API).
Parents worry about children going outdoors, those with respiratory problems reach for their masks, schools and outdoor activities come under scrutiny, and the rest of us complain about the smell, the heat and a sky that seems to have misplaced its blue.
Then begins another familiar ritual: the blame game. Fingers point across borders, satellite maps are examined, hotspots counted, ministers issue statements, companies deny responsibility, and social media quickly finds someone to accuse.
Some blame plantation fires, others smallholders, peatlands, drought, weak enforcement or winds carrying smoke from elsewhere.
There is usually enough complexity for everyone to find a culprit that fits his preferred explanation.
When the haze lingers, perhaps Malaysians of every persuasion share one simple hope, even prayer: let the rains come soon.
For those of us who have spent much of our working lives among oil palms, however, another question arises.
While we debate who caused the haze, what is it actually doing to the crop beneath it?
An oil palm cannot join the blame game. It simply stands there and responds to whatever the sky gives it.
Botanists will rightly object that palms do not think, but they certainly react.
An oil palm is, after all, a magnificent biological solar panel.
Its canopy captures sunlight and turns that energy into leaves, roots, trunk, flowers and, most importantly to the planter, fresh fruit bunches.
So when smoke hangs between the sun and millions of hectares of oil palm, something must be happening.
The real questions are how much and when. That last word matters because an oil palm has a long memory.
When someone dims the lights
Oil-palm scientists were studying the importance of sunlight long before haze became a familiar regional headline.
R.H.V. Corley was writing about photosynthesis and oil-palm productivity decades ago, while later work strengthened our understanding that bunch production is closely tied to the light intercepted by the crop.
I.E. Henson brought those ideas directly into the haze question in his 2000 Journal of Oil Palm Research paper, Modelling the Effects of ‘Haze’ on Oil Palm Productivity and Yield.
His basic proposition was straightforward: reduce the light available to the palm and photosynthesis suffers, with potential consequences for growth and eventually yield.
In simpler language, the palm needs enough photosynthetic income before it can spend generously on bunches.
But biology becomes more complicated once we leave the textbook and walk into the field. Haze does not simply turn down sunlight. It may occur alongside changes in temperature, humidity, rainfall and water stress, all of which can modify the palm’s response.
Hazy or cloudy conditions may also increase diffuse light, allowing some sunlight to penetrate the canopy more evenly. So biology refuses to give us a convenient equation of more haze equals proportionately fewer tonnes of fruit.
There is another complication: time. As I wrote previously in The Star about oil palm, rain and El Nino, every bunch is the finale of a biological story that began long before we see it.
Reproductive development takes place over an extended period, with environmental conditions influencing different stages long before the eventual bunch reaches the harvester.
A drought today therefore does not necessarily produce a crop loss tomorrow. Its effects may emerge later through changes in flowering, bunch survival and the balance between male and female inflorescences. The palm keeps biological accounts long after the weather has changed.
Haze raises a related but different question. The smoke may disappear after a good thunderstorm, but if reduced sunlight or the conditions accompanying haze disturb one of those developmental stages, the consequence may arrive much later. The sky may clear quickly, but the palm keeps a longer calendar.
Love, perfume and a very small courier
Sunlight, however, is only half the story. Anyone who has worked in oil palm knows that producing a good bunch requires more than sunshine, fertiliser, rain and a competent estate manager. Somebody still has to arrange the marriage.
Oil palm produces separate male and female inflorescences on the same palm. Male flowers provide the pollen; female flowers must receive it before normal fertilisation and fruit development can follow.
In the “secret love life” of the oil palm, there is quite an elaborate courtship beneath those fronds - complete with perfume and a very small Cupid.
That Cupid is Elaeidobius kamerunicus, the pollinating weevil. Its arrival is one of the great, if under-appreciated, stories of Malaysian agricultural science.
For years, the importance of insects in oil-palm pollination was not fully understood. Research by the late entomologist Rahman Anwar Syed in West Africa changed that understanding by demonstrating the role of Elaeidobius species in natural pollination.
Following further evaluation, E. kamerunicus was introduced into Malaysia in 1981. The effect was transformative. Assisted pollination, once expensive and labour-intensive, became largely unnecessary, while natural fruit set improved substantially.
No salary, no annual leave, no Socso and, fortunately for estate managers, no housing allowance - yet this tiny insect performs an enormously valuable service.
The partnership is remarkable. E. kamerunicus feeds and breeds on male inflorescences. Adults become dusted with pollen and then visit receptive female flowers, carrying out the delivery that allows fertilisation to occur.
The palm even provides its own advertising, with flowering inflorescences releasing distinctive scents that attract the weevil.
In layman’s terms, let us compare E. kamerunicus to a GDEX or DHL courier. The parcel is pollen, the destination a receptive female flower, and the delivery window brief. Nature solved last-mile delivery long before we invented the term.
This brings us back to haze. I would describe oil palm, rain and El Nino as something of a love triangle. Haze now introduces an intriguing fourth party.
If severe haze changes sunlight and the surrounding environment, does it also alter weevil behaviour? Does the insect fly less? Could smoke interfere with the floral scents guiding it? Could particles settling on flowers or insects affect pollen transfer? Could prolonged haze influence flowering or pollen quality? And ultimately, could any of this reduce fruit set?
Here the scientific answer becomes surprisingly unsatisfactory: we do not really know.
At least, I could not find convincing field research demonstrating the complete chain from measured haze exposure to reduced E. kamerunicus activity, poorer pollination and subsequently poorer fruit and kernel formation.
That does not mean the effect does not exist. It means we should resist saying that it does until someone measures it properly. Sometimes the most useful discovery in research is finding the hole in our knowledge.
The bunch keeps the score
What we understand much better is what happens when pollination deteriorates. A revealing Malaysian Palm Oil Board study published in 2002 deliberately produced different levels of pollination in 12-year-old DxP palms at Bangi.
Among 70 bunches studied, fruit set ranged from just 2% to 96%, while naturally open-pollinated bunches averaged about 80%. Bunch weight increased with fruit set, reaching about 24kg at around 90% fruit set.
The study tells us more than those numbers alone. As more flowers were successfully fertilised, the developing bunch demanded more of the palm’s carbohydrates, and the researchers found relationships between fruit set and both the oil and kernel components of the bunch.
Once fertilisation had succeeded, individual nuts and kernels also appeared relatively well protected even when fruit set varied. For a plant, that makes evolutionary sense: mesocarp oil matters greatly to us; the seed matters greatly to the palm.
Poor pollination is therefore more complicated than simply counting missing fruits. When pollination fails, some fruits may not develop normally, bunch composition changes and the value of what eventually reaches the mill may also change.
This takes me back to my own plant-breeding days. Breeders did not judge a palm merely by tonnes of fresh fruit bunches. We looked at oil yield, kernel yield and their combined economic value. One familiar calculation was Total Economic Product, or TEP: TEP = Oil Yield + (Kernel Yield × 0.6). The 0.6 was not some sacred biological constant handed down from the oil-palm gods. It was an economic weighting recognising that kernels carried value too. The coefficient matters less here than the principle: do not judge a bunch only by its orange oil. There is value inside the nut too.
That makes the haze-pollination question economically interesting. If environmental stress were eventually shown to reduce pollination, the loss might appear not only in fresh fruit bunch yield or oil extraction rate, but also in fruit set, kernel recovery and the overall value of the bunch. Kernel Extraction Rate (KER) deserves a seat at the table too.
One palm, several clocks
There is one final complication, and perhaps the most important. Oil palm does not organise its biology according to our monthly crop reports.
At any one time, the same palm is carrying reproductive stages whose consequences will emerge at different points in the future. Environmental stress today may influence one developing bunch relatively soon and another reproductive process much later.
This is what makes El Nino troublesome and haze difficult to disentangle from it.
Severe regional haze often accompanies dry conditions. The palm does not receive separate invoices marked Drought, Heat, Haze and Reduced Sunlight. It experiences them together.
When production eventually falls, which culprit gets the blame? Water shortage, reduced sunlight, heat, changes in flowering, poorer pollination - or several stresses acting together?
Here the plantation version of the blame game can become as misleading as the public one.
There is a temptation, especially for someone who has spent a lifetime around palms, to connect the dots. Haze reduces sunlight; weather affects weevils; weevils affect pollination; pollination affects fruit set; fruit set affects bunch weight, oil and kernels. Therefore haze must reduce Oil Extraction Rate (OER) and KER through poor pollination.
It makes a beautifully tidy story. Unfortunately, science does not award marks merely because the arrows line up nicely.
The outer links have evidence behind them.
We understand much about how light and water affect palm productivity, how E. kamerunicus transformed pollination and how fruit set influences bunch composition.
What remains poorly understood is the crucial middle link: does haze itself alter weevil behaviour or pollen transfer enough to impair pollination?
That is the experiment worth doing. A properly designed field study during future haze episodes could measure haze severity and sunlight alongside rainfall and soil moisture, flowering, pollen quality, weevil abundance and activity, fruit set, bunch composition, OER and KER.
The palms should also be followed long enough to capture delayed effects rather than declaring the experiment over when the sky clears.
The industry need not wait for the next severe haze before designing such work, because haze, unfortunately, has a habit of returning.
There is a larger lesson here. Agriculture teaches humility because so much of what determines our harvest happens beyond ordinary sight.
We notice the harvester because he carries a sickle, the tractor because it makes noise and the mill because smoke rises from its chimney.
We hardly notice a little brown-black weevil crawling through an inflorescence with grains of pollen clinging to its body, yet part of the harvest depends on that tiny journey from one flower to another.
The oil palm industry has become remarkably good at measuring tonnes, extraction rates, rainfall, fertiliser, labour productivity and carbon emissions.
When the skies turn grey, perhaps we should add another question: can our weevils still work effectively in the haze?
More than four decades after Elaeidobius kamerunicus joined Malaysia’s plantation workforce, we still have much to learn about what happens when someone turns down the sun.
Eventually, we pray, the rain comes, the API falls, the hills reappear and the blame game moves on.
In the plantation, however, the palms continue quietly developing flowers and bunches whose fate may have been shaped long before harvest.
The haze disappears. The palm remembers.
Joseph Tek Choon Yee has over 30 years of experience in the plantation industry, with a strong background in oil palm research and development, C-suite leadership and industry advocacy. The views expressed here are the writer’s own.
