The teenager, who is not named due to his age, lit the fires a day after he injured a 74-year-old man when he followed instructions from a 12-year-old boy to throw a stick at the man.

The man had been walking alone through Peace Park in Bathurst when he was set on by the two boys about 10.50am on September 12. He managed to cover his face with his forearms but received small cuts to his arms that bled.

The boys ran away after a person on the other side of the Macquarie River saw what was happening and called out.

The two boys, who were living in the Orange area, then stole two BMX bikes by using bolt cutters to cut their chains in a shopping centre car park.

After they returned to the centre, security called the police who arrested the 16-year-old but chased the 12-year-old for several blocks before he was caught.

Solicitor Andrew Abraham said the 16-year-old was never the instigator and he was "genuinely sorry".

"There is a good chance of rehabilitation if he does get bail," Mr Abraham said.

According to police, the teenager used a lighter to ignite dry grass in the middle of a paddock about 3pm the next day, and then lit another fire in dry leaves.

An adult at a nearby house saw the fires and a fire extinguisher was used to put out the flames, although one fire ignited a second time.

Neither fire spread very far.

The 16-year-old was in custody for about three weeks when he appeared via a video link in court for sentencing.

He was convicted and given a 12-month probation order for assaulting the 74-year-old, he was also convicted and he was placed on a good-behabiour bond for stealing the $300 bike.

For lighting a fire and being reckless to its spread, and leaving a fire without extinguishing it he was convicted and given two six-month good-behaviour bonds.

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