get an even number 10 foot sections of conduit, about $4 each. cut half of them in half. cut the other half of them in half but cut it at a sharp angle, like about 60 degs.

the pointy ends go in the ground. about 12 inches above the pointy end, drill a 3/8 in hole all the way through. put a 2-3 inch nut and bolt through the hole. you put your foot down on this to drive the pointy end in the ground. these pointy conduit sections are also good at deterring annoying people.

on the other end of the pointy section, get a big dowel rod that fits snugly inside, you need about 8-12 inches. glue half of it in the pointy dowel section.

now with the other sections of conduit, you can just slide them onto the dowel. drill some 1/4 inch holes near the top and insert some 1/4 x 36 dowels, these are your branches where the dekes sit. you might have to put some tape on the end of the dowel to make it snug. paint the whole thing flat black or brown or grey and your set.

to carry, get a few bungee cords and wrap the 5 foot sections. then get some 1 inch nylon web strapping and some d rings and loop them around each end. or you can make a big quiver, a big robin hood type of quiver.

if the ground is hard, you may have to pour some water on the spots you want the trees, or find some cracks and drive the pointy ends in there.