Long-serving officer David Mackay, 40, who is on trial accused of deliberating setting fire to land in Argyll, would have earned double the hourly rate for the work due to it being a Bank Holiday, a colleague told Fort William Sheriff Court yesterday.
The sum would have been in addition to his monthly retainer, jurors were told.
Mr Mackay has pleaded not guilty to deliberating starting the blaze in a forest at Glen Tarbert, near Strontian, and on crofters' grassland near the area on April 1, 2013.
He has also denied deliberately starting a fire at the Carnoch Estate near Strontian, Argyll, which destroyed part of the forest, on March 27 last year.
Mr MacKay was a part-time fireman in the local brigade in Strontian for 20 years and received a long-service meda.
Fire chief Alastair MacLean,48, told jurors his colleague worked full-time for Scottish Water, but in his spare time was one of his two crew manager deputies.
It took two days to extinguish the first fire with the aid of units from other villages and a water-dropping helicopter.
Mr MacKay, of Strontian, turned out to fight all three fires, the court heard.
Mr MacLean told the court: "We all get double the hourly rate for fighting fires on a public holiday. We also get a monthly cash retainer.'
He told defence lawyer Rosalyn MacTaggart: "You have to have trust in your colleagues. I have trust in David. Like most of our crew he was a very good fire-fighter."
He added: "We fight fires. We do not investigate them.'
Mr Mackay's former girlfriend has told the court that she saw him near where one of the three forestry and grass fires started.
Health care assistant Sheila Henderson, 31, told Sheriff Mungo Bovey that at one time she had been in a relationship with MacKay for eleven years.
She said she was driving to see a patient and saw Mr MacKay's Scottish Water van in Glen Tarbert at around the time of one of the fires. On her way back she saw the blaze and fire-fighters, including her ex-partner, at the side of the road.
Roger Peace, of Forestry Commission Scotland, told the court he was forced to hire a helicopter to enable the Commission to help tackle the forest fire, and that the cost of the damage was hundreds of thousands of pounds.
The court also heard from an employee of Scottish Water, Sheena McConnachie, who said the quango's vans had tracker systems that allowed their locations to be traced.
The trial is due to continue today.