Fictional Scenario - Suppose you are out camping and are stuck somewhere. You want to create a signal of white smoke to attract help.
So what are the naturally occurring substance which when burnt would produce dense white smoke ? e.g. leaves or fruits or some extracted sap from some tree.
Wet wood does not count.
In hindu festivals especially during Durga Puja dried coconut fibres (the exocarp of coconut fruit) are lit and then crystals of Dammar gum are sprinkled over it which produce dense white smoke with a characteristic smell. The smell is due to Dammar gum powder which is colloquially called dhuno.
By exocarp or dried coconut fibre I mean the brown portion of this cut coconut.
NOTE: Dammar gum is the resin of Dipterocarpaceae trees found in India and East Asia.The gum varies in colour from clear to pale yellow, while the fossilised form is grey-brown.
You can build a so called "smoke generator" and feed it with certain material to specifically generate white smoke. It's basically a survival technique.
First, make a platform from dead wood, and stack it as shown in the illustration. Stack the wood 4 or 5 high, and make it fairly large, perhaps 4 feet in length. Then cover it with evergreen boughs, either pine or cedar, and have an opening below where you can insert a burning brand, limb, or other source of fire.
When ignited, use caution and move away instantly because it will flare up suddenly. The smoke produced will be a dense white smoke and the flames will be high. You could easily be burned, so ignite the boughs and quickly move away.
From Simple Survival - How to use a smoke generator
To generate white smoke, feed it with:
After you have a good fire going, add grass and green sticks and branches to your fire. This will smother the flames and create a dense, white smoke.
From "How to send a smoke signal"
Try to create a color of smoke that contrasts with the background; dark smoke against a light background and vice versa. If you practically smother a large fire with green leaves, moss, or a little water, the fire will produce white smoke. If you add rubber or oil-soaked rags to a fire, you will get black smoke.
From Wilderness Survival - Signaling Techniques
Comprehensive article from Wilderness Survival:
During daylight, build a smoke generator and use smoke to gain attention (Figure 19-2). The international distress signal is three columns of smoke. Try to create a color of smoke that contrasts with the background; dark smoke against a light background and vice versa. If you practically smother a large fire with green leaves, moss, or a little water, the fire will produce white smoke. If you add rubber or oil-soaked rags to a fire, you will get black smoke.
In a desert environment, smoke hangs close to the ground, but a pilot can spot it in open desert terrain.
Smoke signals are effective only on comparatively calm, clear days. High winds, rain, or snow disperse smoke, lessening its chances of being seen.
