Picture how an orchard bench terrace is actually used. It only has to give one line of fruit trees a flat footing on a hillside, unlike a field bench terrace that must hold an entire cropped strip.
Since only a single tree row sits on it, there is no need for a wide platform, a narrow shelf is enough, and this is why orchard bench terraces, also known as step or intermittent terraces, are kept close to 1 metre wide.
The wider widths of 2 m or 3 m belong to regular field bench terraces meant for row crops, and 0.5 m is too narrow even for a single tree base.
\[ oxed{1\ m} \]