The texts originating from the three sources quoted here above describe precisely and in similar terms the beings with remarkable capacities found in nature and therefore, in connection with the Earth. Such beings are not usually involved in the world of the humans, yet they may sometimes manifest themselves in our physical world. That's how Spiritual Science describes them:
They are very intelligent beings with very extensive level of knowledge, comparable to the humans' level of knowledge;
they have physical bodies made of subtle matter - Spiritual Science refers to “sub-matter”, a matter density level still unknown by today's Science - and that is why they are invisible to us. That means they are found in a different dimension or at a parallel level;
yet, they do not have a spirit (even if, by misuse of language, they are often called spirits of Nature). The spirit represent the immortal part of being;
they will make fun of men and may play all kinds of tricks on them;
and last, they are able to assume all kinds of shapes, light or material shapes. H.P. Blavatsky specified that theses shapes could be condensed so as to become tangible.
This is how Patrick J. Petri describes the reality of the nature beings: “The world of Elementals is quite as real as the animal or the flower, even if it is no longer perceptible by our senses. Modern thought which is rational and scientific, while giving to man the opportunity for a marvelous investigation of the matter, has darkened or reduced his field of vision, leading him to ignore a whole part of the real. That was a necessary stage in human evolution, but time has come perhaps for mankind to open up again to new realities”.
After reminding all this knowledge ignored by science yet originating from different and convergent sources, we realize that there are all kinds of factors to consider for the “seekers of truth” in their effort to elucidate the nature and the origin of the UFO-type and Crop-circle type phenomena.