This is an Ash Release technique which mimics an Ice Release technique known as Demonic Ice Mirrors. It was developed by Ōhoyamatsumi during his training with Arienai, and was used often to ambush foes while avoiding direct combat. The Hiding in Ash Technique is required to be used before this technique can be activated, though the end result is a trap which is capable of setting up for a very elaborate strategy.
Using the ash which must have been previously dispersed throughout the area and to coat the ground, the user creates hundreds of solid black pillars which resemble trees upon first glance, even possessing "branches" and "roots", though these are really tendrils which may be used to sense chakra if the user is indeed a Sensor, much like Ōhoyamatsumi's case. The pillars all vary in size, although most of them are tall enough to easily tower over someone. The user will "enter" a pillar through it's roots in a manner similar to the Hydration Technique, and may cause parts of their body to emerge from other pillars at any time to attack a foe with some sort of weapon, or even an eye technique such as Amaterasu. Because all the tree roots are networked together, the user may near-instantaneously travel from pillar to pillar at will. While not an offensive technique on it's own, it is more than capable of setting up for other techniques, giving it the potential to be used as a part of a collaboration technique.