Ecological field of single spruce trees in greenmosses pine forest and in dry meadows are investigated in the southern Karelia and in the north-western Leningrad Region. The transformation of ecological factors (light, temperature, passing of precipitations by a canopy, power and humidity of soil horizons) by the spruce is studied. An original formula involving various tree parameters is used for the evaluation of each tree influence degree. It is shown that the spruce influence on other plants regularly decreases with increasing the distance from the trunk. The ecological field boundaries on the base of species cover are not far removed from the canopy edge; however, according to environmental factors, especially the light, the ecological field goes out far beyond the canopy edge. Four types of plant species reaction on the ecological field influence are distinguished: displacement, displacement-adaptation, adaptation, neutral type. Displacement is the commonest form of interactions, typical of more than a half of the species studied.