Wood Release

is an advanced nature kekkei genkai that combines earth and water-based chakra natures to create wood, or complete trees. This ability can also be used to create other aspects of trees, such as seeds or flowers. Wood Release techniques can be produced from anywhere, including the user's body, as the user's chakra is literally converted into a source of life. are commonly affiliated with the Snake seal.

Overview
Hashirama Senju was the originator of this ability, evidenced by the fact that no other member of his clan were known to possess this ability. His ability to use these techniques was one of the reasons for him being given the title of the First Hokage, and with Wood Release Secret Technique: Nativity of a World of Trees he was able to grow the trees that served as the foundation of Konohagakure. This technique allowed him to completely reshape battlefields to his advantage. Since then, several people have come into possession of this kekkei genkai. However, their use of this ability has been noted to be on a weaker scale to that of Hashirama.

Madara Uchiha, after his confrontation against Hashirama Senju at the Valley of the End, acquired a portion of his DNA and became able to use Wood Release as a result, which was demonstrated upon his reincarnation and subsequent fights on the battlefield.

White Zetsu was created from the First's cells, by Madara, and as such, he can also use it, albeit on a weaker scale. As noted by Tobi, the First's powers are not so easy to control. This was witnessed when Danzō was on the verge of death, the overwhelming life force of the Senju tried to "swallow him whole" and his entire right side started turning into a tree.

Obito Uchiha gained Wood Release through Hashirama's Living Clone being implanted into him by Madara after being mortally wounded during the Kakashi Gaiden.

Orochimaru, in his quest to harvest the First Hokage's abilities, injected his DNA into sixty test subjects, and out of the sixty only Yamato survived. With his own DNA overridden, Yamato gained the ability to use Wood Release. Orochimaru also performed a similar procedure on Danzō Shimura by implanting the First's cells in his right arm. While Danzō is capable of using this power, it appears Danzō's version is much cruder and causes a much more significant drain of chakra with each usage, causing Danzō to avoid using it as much as possible.

A derived technique of the Wood Release is the Hokage-Style Sixty-Year-Old Technique — Kakuan Entering Society with Bliss-Bringing Hands. This technique produces a seal on the user's right hand that can suppress a tailed beast's influence over its host. This is done by producing wooden dragons from the ground that attach to the host and force the tailed beast's chakra to recede. Hashirama's necklace aided in this technique's execution, but its exact purpose was unclear. After Naruto destroyed the necklace however, Yamato implied that he could no longer suppress the Nine-Tailed Demon Fox's influence. Nevertheless, during Naruto's training to control the Nine-Tails at the Falls of Truth, when he was transforming, Yamato stated that he would try to suppress the beast. Whether or not this would have worked was never seen due to the transformation stopping.

Trivia

 * Wood Release parallels the real-life ninja art . One example of real-life mokuton-no-jutsu is Tanuki-gakure: the practice of climbing a tree and camouflaging oneself within the foliage.
 * In the anime, the Moulding Mushroom appears to drain chakra from Wood Release users.
 * Madara Uchiha and Danzō Shimura both grew replicas of Hashirama's face on their bodies after integrating his cells into their bodies.