When triggered, this leaves whatever triggered the snare hanging from the tree branch by whatever limb set off the trap.

There's always six feet of rope between victim and tree branch. For a six foot human, this requires about 15 feet between ground and branch to work correctly. The snare has a maximum length of 10 yards, so there can be no more than this distance between the ground and the branch.

All characters get a no-consequences contest of ST vs. the trap's ST to escape as the trap goes off; this is to represent the character's weight straining the trap as it lifts them. If they succeed, then the snare broke under the sudden strain.

Once the trap has lifted them, escape involves falling damage from whatever height the character ended up at, unless they can somehow climb up.

If the snare somehow catches the neck, this spell can strangle.

This is targeted at the tree branch via the Innate Attack (Projectile) skill.

The snare has DR 6, HP 18 and can be destroyed before it's set off.

Binding 18 [18] 
    Triggered Delay [+50%] 
        Touching the ground of the same hex as the snare 
    No Signature [+20%] 
        -8 to rolls to notice the snare 
    One-Shot [-10%] 
    Environmental (Only works under a high tree branch) [-40%] 
        This branch much be high enough to hold the victim off the ground 
            with six feet between them and the branch 
        This requires a successful attack roll at the branch 
        This doesn't work on a branch more than 10 yards off the ground 
    Reduced Range (x1/10) [-30%] 
    Magical [-10%] 
    Spell Components [-30%] 
        Must say "snare" in Latin 
        Must wave a rope in the air