In Jainism, plants and trees are not counted as Pṛthvīkāy (earth-bodied beings) because:

1. Clear scriptural classification of 5 kāy (bodies)

Jain Āgams and later texts divide one-sensed (ekendriya) jīvas into five main groups: - Pṛthvīkāy – earth-bodied - Apkāy – water-bodied - Teukāy – fire-bodied - Vāyukāy – air-bodied - Vanaspatikāy – plant-bodied (all plants, trees, grass, crops, etc.) ( jainknowledge.com)

So, plants and trees are specifically put in Vanaspatikāy, not in Pṛthvīkāy.

1. Basis of classification = type of body, not location

- Pṛthvīkāy = jīvas whose body is of earth-substance (soil, stone, metals, etc., in natural, undivided state when enlivened by a soul). ( jainknowledge.com) - Vanaspatikāy = jīvas whose body is of plant-substance (stem, leaves, roots, fruits, trees). ( jainknowledge.com)

Even if a tree is growing in the earth, its own body is not earth, it is plant-material. So it cannot be called Pṛthvīkāy.

1. Ahimsā viewpoint

- Harming earth (soil, stone, etc.) = himsā of Pṛthvīkāy. - Cutting a tree or leaf = himsā of Vanaspatikāy. Jain ethics need these categories to know which jīva is harmed and how serious the violence is.

1. No Digambar–Śvetāmbara difference here

Both traditions accept the same five dravya-kāy classifications, and both put plants/trees under Vanaspatikāy, not Pṛthvīkāy.

You can read more about these kāy classifications here