Tree climbing ropes are made from many different materials and come in different constructions as well. These ropes are meant for life support and have the strength to prove it! Most ropes are made with polyester and a blend of other technical fibers for strength, knotability, and suppleness.
12 strand ropes hold up very well to abrasion and are great for climbers that don't use friction savers. These ropes have more stretch than some of the other ropes and have a solid braid construction making inspection very easy.
16 strand ropes feature a cover and a core but all the strength comes from the cover. This makes the rope very easy to inspect for damage. 16 strand ropes are generally stronger than 12 strand ropes and still have great abrasion resistance. These ropes are great for climbers using a Blake's Hitch and a natural crotch tie in point.
24 strand ropes are great to use with friction savers and ascenders. Many SRT climbers use 24 strand ropes because it still has stretch in case of a fall but is still static enough for easy ascent. 24 strand ropes are not as abrasion resistant as ropes with less strands but they do offer a higher breaking strength and they keep their shape better than other ropes.
Static ropes are made up of 32-48 strand covers that allow ascenders to bite into without causing damage. Static ropes have very low stretch making them great for ascending into trees using SRT climbing techniques.