Complex sentence: The degree to which horticulture or small-scale agriculture was practiced by Jōmon people is debated, but there is evidence to suggest that arboriculture was practiced in the form of tending groves of nut-and lacquer-producing trees.
Split into simpler sentences: The degree to which horticulture or small-scale agriculture was practiced by Jōmon people is debated. There is evidence to suggest that arboriculture was practiced in the form of tending groves of nut-and lacquer-producing trees.