THE HORSE STILE
This stile was first used in Australia to allow horses in to areas where they didn't want trail bikes or other vehicles. Apparently they tried several ideas, but this was the one that worked the best. The stile is set into the fence line, and does not necessarily have to be on a formed track or next to a gate.
We have seen it in use at Belmont Regional Park (near Wellington) when we were part of a group which included large horses and small ponies, plus our two horses who had never seen anything like it before - all of them coped perfectly well with it. If you have any doubts about your horse going through it you could practice with cavaletti at home first.
Here is a drawing of the stile. The construction does have to be quite strong. It can be made from metal pipe as an alternative to wooden posts and poles. With wooden poles it may be a good idea to reinforce them with angle iron so that they can withstand someone trying to drive through them or chainsaw through them (or perhaps even a horse accidentally stepping on them). Alternatively, a piece of heavy wire stapled to the sides of the poles can be a good chainsaw deterrent.
In the Wellington region we have found the people managing recreational areas are keen to see more use of park areas and trails, including horse riding. It is only in areas that are really popular for picnics and short walks that there can be a conflict between the general public and riders. In other parts trampers and horse riders use the same trails with no problems. The problem is keeping out trail bikes and unauthorised 4WDs, and this usually means locked gates which effectively exclude horse riders as well. Often you can get a key, but they don't want to issue lots of keys because then it is easier for the wrong people to get hold of them and then the bikes etc are back in again. The Horse Stile is a better way of ensuring access for horse riders while still keeping vehicles out.