There is no perfect timber for decking, however below is some of the “Pro’s and Con’s we have encounted of the more popular species.
Stable / minimal swelling / movement
Less likely to encounter mould/mildew
Less likely to encounter splinters
Can last a long time even if it's not coated with decking finishes
Leaches tannins until sealed
Environmentally not popular as there has (in the past) been widespread illegal felling in Asia
Many people do not like the reddy brown colour of the timber
One of the most popular timbers for decking
Generally comes from either NSW (lighter brown colour) or QLD (normally a redder colour)
Often attracts moisture and mould
Prone to rot in lighter heartwood areas
Coatings tend to need to be re-applied more often than other wood
Easily absorbs moisture and therefore prone to swelling/cupping
Should be used in areas of good ventilation so it can dry out or with larger gaps between boards
Often can be prone to splitting / cracking / twisting
Can leach black/brown tannins
Comes in grey/red/brown hues
Attractive grain, quality feel
Interesting mix of grain and colours
Does not leach tannins as much as other wood
Not as durable as some other hardwoods as minimal tannins in timber
Can easily absorb moisture and cup/swell and splinter
Plantation grown so environmentally friendly
Light in colour and weight
Uneven grain, density and knots
Can look and feel budget focussed
Sometimes has the green treatments in timber
After sanding tends to easily have raised grain
Actually a grass not a timber
High sugar content means mould problems
Absorbs moisture easily and easily swells
Man-made with resins means inconsistent quality from different suppliers