Polish to English Science Forestry / Wood / Timber types of timber hauling truck and trailer units

This is a type of trailer hooked up to a truck which is used to transport harvested timber. The word kłonica means stanchion or stake, which probably refers to the supports used on the trailers to keep the logs in place. But, the other types of tractor and truck units also have such stakes. I am looking for the English name for this type of trailer. In the photo I have, it looks like the front and rear axles of the trailer are not connected by a platform, as the long logs seem to keep the front and rear together. The front and rear are connected to each other and the truck by a thick cable (probably for the lights) (a = truck + trailer; b = tractor unit + semi-trailer; c = tractor unit + lightweight platform trailer; d = tractor unit + ??)

Przykłady zestawów wywozowych: a) samochodu i przyczepy, b) ciągnika siodłowego i naczepy, c) ciągnika siodłowego i lekkiej naczepy platformowej, d) ciągnika siodłowego i wózka kłonicowego