From a Feng Shui perspective, it is not good for trees to grow on graves.
The first thing that can be explained by the trees growing on the graves is that as children or descendants, they do not regularly visit the graves during the Qingming Festival or other times. We all know that it will definitely take a long time for a tree to grow into a tree, and if future generations will visit the tombs to pay homage to their ancestors every year during the Qingming Festival. Then, it is impossible for a tree to grow on the grave. From this point, we can see that as a descendant, from the perspective of traditional Chinese moral concepts, it is an expression of unfilial behavior.
Secondly, the growth of the tree requires a lot of nutrients. It will absorb the nutrients from the grave and the surrounding soil. From a Feng Shui perspective, this is equivalent to the water being extracted from the area. If it is dry, then it means that the water in Feng Shui is gone and only the wind is left. It also has a great impact on future generations, whether it affects wealth or other fortunes.
You must know that a tree will have a very developed root system, with many root systems, big roots and small roots. Therefore, if it grows on the grave, its root system will grow downward, the longer and deeper it will grow, and it will inevitably grow to the coffin. Slowly, the roots of the system will grow into the coffin and affect the ancestors. According to Feng Shui, if the "home" of ancestors is threatened, it will also affect future generations.