A prevalent theme in global myth and mysticism is that of trees and their connection to human creation, cosmology, and consciousness. Philosophy aside, the scientific inquiry into human relation to trees illustrates clear biological and psychological changes in human evolution. The reverence concerning trees may in fact then be built into genetic memory as some evolutionary biologists and psychologists claim. It is argued that many symbolic representations concerning trees are related to the subconscious mind since, for an extended period of the human evolutionary timeline, they provided a semblance of safety, gifts of food and a few hidden dangers. This presentation will discuss some of the physiological and psychological features of the human relationship with trees. The physiological adaptations caused by the human relationship with trees over millennia is evident. Most of the mammalian life of the Mesozoic era, roughly 252 to 66 million years ago, was spent hiding in crevices and darkness from the reptile dominated land. Trees provided much of the safety during this time. Even after the last major extinction which opened the world up to mammal dominance, the line that will evolve into primates and eventually humans persisted to seek safety and food in trees. Though anatomically modern humans have adapted to a bipedal locomotion and a ground-based lifestyle, some of the physiology of humans display remnants of their time as tree-dwelling creatures. The most prominent of which is the opposable thumbs, powerful grip and eyesight. Over time, the human ancestors began walking more upright, lost their canines, and increased their brain capacity among other adaptations. Evidence suggests that although bipedalism was present during the time of Australopithecus, beginning roughly 3.5 million years ago, the use of trees or an arboreal lifestyle remained common. It was only later when the genus of homo emerged, roughly 2.3 to 1.4 million years ago, that we truly started to live terrestrially. Thus for the majority of our existence as a primate, and even before that, trees served as homes, sources of food and provided more safety than the ground. Some genetic features of this lineage remain which plays an integral part in modern life. This includes the spectacular ability to have a firm grip with opposable thumbs. With a firm grip, ability to craft with finesse and an increase in brain size, humans could develop civilization into what it is today. By using the strength of their hands and upper bodies developed by climbing, the subsequent use of tools could be crafted and wielded with power. The nimble use of human fingers allowed for careful, detailed crafting which led to advances in technology. To this day, human grip and digits remain a vital part of the way we live and interact with the world. The way human sight functions is another remnant of time lived in the trees. This refers to the development of binocular vision and trichromatic view. It is thought that forward-facing eyes, or binocular vision, developed in trees as to provide a more detailed three-dimensional image of what is in front of us. This creates an accurate estimation of distance, allowing for rapid movement in trees and more reliable vision to notice food, such as fruit and insects. In contrast, most large terrestrial plains herbivores have a broad field of view with the eyes at the sides of the head for easier spotting of movement and predators at a wider angle. While mostly predatory animals tend to have forward facing eyes. The ability to see in color is another trait that most mammals lack. Humans have a trichromatic vision which enables them to perceive the visible light spectrum. Most mammals have a dichromatic color range, which allows for the perception of shades between two colors rather than three. This is thought to have developed to easily find colorful ripe fruit in trees. The ability to perceive a range of color improved to odds of spotting fruit color, instead of shapes over farther distances. Thus, it is thanks to the development alongside trees that the world of humans is vivified by spectacular colorful displays. Other than physiological remnants, evidence also suggests that this connection is engrained in the human psyche. It has been illustrated that natural areas or features, especially trees have a calming and healthy effect on the human mind. Whether this is due to an evolutionary memory of safety is unclear, however, remains a viable option in the fields of science. This phenomenon is closely associated with the "biophilia hypothesis" which suggests that humans have an innate tendency to seek out and connect with the natural world from where they stem, or to at least enjoy it. Since trees played a major positive role in human development, it may be no coincidence that its reverence and symbolism is so marked in philosophy and spirituality. Also concerning the psyche, many spiritual traditions globally have symbols and lore attributed to a creator, cosmic, or world tree. Even though these traditional thoughts may be spread across vast distance and traditions, similarities in iconography, tales, and lessons appear in their description. This includes their connection to higher and lower realms, other entities, serpent symbolism, medicine, magic and much more that seem to defy the odds of coincidence. These similarities have baffled scholars for a long time and have only recently come to be explored in more detail. The primary theory for this remains that genetic memory plays a vital role in the archetypes that the human subconscious mind associates with. Which means that trees and features closely related to them create strong subconscious mental and emotional associations not necessarily based on individual life experience, but genetic ancestry instead.
More physiological and psychological remnants of the evolutionary time spent in trees are evident, however, of all, the use of our hands and vision remains some of the most significant. While parts of our psyche have deeply ingrained memory of the importance of trees and our connection to it.