Q.Loquat Tree
This year leaves became yellow and falling down in big numbers. This is not a young tree, but I do not know the age. Some portion of roots extend from the soil level. Please give me advice.

Certified GKH Gardening Expert
There are many reasons a tree can get yellow leaves. This article will cover some of those reasons: https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm That being said, tree diseases are very hard to diagnose without seeing the tree, so I would recommend hiring a local tree specialist to come look at the tree and advise you on it.