Wood Release Jutsu was created by the first Hokage Hashirama Senju. He made the forest which served as the base for Konohagakure and it also led to him becoming the first Hokage.

The Wood Release allows the user to convert their chakra into a source of life. The vegetation can sprout from the user's body or grow in their surroundings. The wood constructs can range from cages to complete houses.

The wood doesn’t need to take a normal form, it can also allow the users to use it as a barrier against brute force. It can also let the user perform intricate things like changing their physical selves and taking on another person’s appearance.

By using Sage Mode, Hashirama could construct a giant wooden statue that dealt a barrage of punches which led to the formation of the Valley of the End. The Wood Release can also manipulate, suppress or absorb the other person's chakra. This technique helped Hashirama subdue the Tailed Beasts and keep them under his control. He even distributed some of the tailed beasts to the early hidden villages during the first Kage summit.

Sage Art Wood Release: True Several Thousand Hands

By using it to create a titanic wooden statue delivering an enormous barrage of punches, it could strip the Susanoo from the Nine-Tails plus be chiefly responsible for the formation of the Valley of the End.

Hokage-Style Sixty-Year-Old Technique:

This Kakuan Entering Society with Bliss-Bringing Hands technique allows the user to put tailed beasts into deep slumber. This technique can be used to suppress a jinchūriki’s chakra before or during transformation, or directly on a tailed beast.

Sage Art: Gate of the Great God:

It allows the users to bind and hold together targets, even those as large as the Ten-Tails.The user manifests a select number of massive red gates that fall down from above, in order to pin an intended target between the gate and the ground.

Hashirama Senju

Hashirama had obtained Wood Release naturally and he alone was able to master it while none of his descendants had inherited it. He had not inherited the Wood Release from anyone else either. After his death, Konoha sanctioned several attempts to learn Wood Release but they all failed and it was now considered forbidden. This was because anyone who obtained Hashirama's cells could not handle it well and they got killed instantly.

Yamato

After Hashirama's death, Orochimaru dug out his body and extracted his cells. He then infused these cells into sixty test subjects in hopes that one of them would be able to acquire Wood Release. Out of the sixty subjects Yamato was the only one to survive and he successfully obtained Wood Release. He became a double of Hashirama and could use the same techniques that the First Hokage used. He also relied on Hashirama's necklace which helped suppress the jinchuriki.

Danzo Shimura

Orochimaru also developed a way to infuse Hashirama’s cells into one part of the subject’s body in order for them to use Wood Release. One such person who Orochimaru did this to was Danzo Shimura, into his right hand. Danzo's wood release was quite exhausting for him to perform due to which he avoids using it at all. Instead, he uses the Hashirama cells to prolong the use of the Sharingan implanted in his arm.

Madara Uchiha

Madara acquired Hashirama's flesh and applied it on himself for healing purposes. After acquiring the Rinnegan, he combined Hashirama's flesh with the Demonic Statue of Outer Path to produce mindless clones of himself. Thus with the help of the clones he could replace lost limbs.

In the cases of both Danzo and Madara, a replica of Hashirama's face grows on their body.

Q. Can Obito use wood style?

Obito to a certain level can use wood style but not at the level of Madara Uchiha.

Q. Why is Wood Release so rare?

Wood Release is a kekkei genkai which rarely occurs naturally in humans. It is thus very rare and only a handful of people can use it.

Q. Can Tobirama use Wood style?

No, Tobirama Senju cannot use wood style even though he is related by blood to Hashirama Senju.