A shinboku (神木) is a tree or forest worshipped as a shintai – a physical object of worship at or near a Shinto shrine, worshipped as a repository in which spirits or kami reside. They are often distinctly visible due to the shimenawa wrapped around them.

The related term goshingi refers to trees that are considered sacred or divine in the precincts of Shinto shrines and jingū of Shinto, as well as the forests that surround them and trees that are not grown for logging. It also refers to trees that are owned by shrines or by private individuals and have a special origin in folklore. It may also refer to trees that have been specially cut down for planting or growing wild to be used as timber for the construction of shrines.

Nature worship, also known as Himikura Shinto, is a part of the ancient Shinto religion that originated in Japan. This form of worship is based on gratitude, fear, and respect for kami, life, and nature. Ancient Shinto practices involved using symbolic objects, such as trees, in places where the environment changed as vessels for Shinto bodies.

Over the course of thousands of years, the form and style of Shinto shrines and rituals have been influenced by foreign religions or established independently, leading to the development of various forms of Shinto. Today, there are tens of thousands of Shinto shrines in Japan, many of which were built on the site of shrines in ancient Shinto religion. These shrines may contain sacred trees, iwakura, rock formations, steles, or mounds, and serve as a testament to the history of nature worship in Japan.

In some cases, shrines may not have a physical structure, but rather worship a sacred tree in its natural state. Evergreen trees with pointed branches are often used as tamagushi in Shinto rituals, serving as a substitute for the gods to descend from. The most common type of tamagushi is the sakaki tree, but other species such as hisakaki and ogatama no ki may be used in regions where sakaki does not grow naturally (areas north of the Kanto region).

In general, a tadakushi is a branch that has been cut down to be offered to the gods, while a sacred tree is one that is still rooted in the earth and worshiped by many people.

Kami-yorigi, also known as kanjinboku, are considered to be yorishiro of the gods, and are given special treatment, being decorated with shimenawa. The Nageia nagi is a yorishiro of the gods, and is also decorated with shimenawa. Many of them are Nageia nagi, mochinoki, and cedar.

In addition, some trees are treated as sacred trees, such as the cedar trees at Ise Grand Shrine, which are regarded as special trees separate from the gods in order to maintain the scenery or create a solemn atmosphere. For those who work in the mountains, a tree that stands out as a substitute for the god of the mountain may be temporarily treated as a sacred tree and enshrined.