Young leaves piled downhill are red.

What you want to ask is why the young leaves piled downhill are red? The content of anthocyanin in leaves is greater than that of chlorophyll. The content of anthocyanin in leaves just grown from tender leaves is higher than chlorophyll, and the leaves are red. With the passage of time, chlorophyll in new leaves is gradually dominant, and the chlorophyll content is greater than anthocyanin content, and the old leaves are green. Downhill pile is a bonsai pile blank with its roots and stems severely cut off.