1. The maintenance cost varies with the size of the trees to be maintained. Generally speaking, the bigger the tree, the higher the maintenance cost.

2. The farther the trees that need to be maintained are from the densely populated residential areas of cities or towns, the higher the maintenance cost.

3. The farther the trees need to be maintained, the higher the maintenance cost.

4. Where trees need to be maintained, the higher the house price, the higher the maintenance cost.

5. The higher the value of trees that need to be maintained, the higher the maintenance cost.

6. The places where trees need to be maintained are more concentrated, the number is more, the water source is closer, it is more convenient for workers to go to work and the cost will be lower.

To sum up, for evergreen trees with DBH of 20 cm, trees with a value of about/kloc-0.5 million yuan should be maintained in high-grade villas in urban areas, and the cost should not be lower than that in 300 yuan. Simply put, the cost is about 2% of the value of trees.