Log agarwood and upside-down agarwood are relatively easy to distinguish from each other in terms of fragrance and shape, but it is not so easy to distinguish between upside-down agarwood and ground agarwood. In fact, many times, even conceptually, it is very easy to be confused.

The causes of inverted shelf and soil sinking are similar, but the difference is that the fragrance of Aquilaria sinensis is better and it takes longer to mellow in the soil, so the fragrance is more rich, restrained and profound.

In fact, stacked incense, agarwood and yellow ripe incense were already distinguished in the Six Dynasties. The ripe fragrance here can be understood as agarwood. Ripe fragrance is the characteristic, because it is as soft as soil when cooked, and it will break when touched. Because it is ripe, the skeleton structure of butter wood fiber is loose, leaving only honeycomb-like fragrant gland tissue, so it is ripe and rotten. Because it is in the soil, it must be agarwood. Cooked incense, heavy or light, will be fragrant. Buried in the soil for a long time, the wood fiber rotted, and the inside and outside were consistent, leaving a part of fragrant gland oil.

According to the color of buried soil, there are loess sinking and red soil sinking, but in fact, these two kinds of agarwood are honey-scented trees, and the color of oil glands is the same, but the real difference depends on the fragrance.