A leafy tree sometimes loses all its lower leaves in a few days. The reasons are as follows: 1, low temperature. Leaf-changing trees should be sheltered from the cold. When the temperature is lower than 18 degrees, they will lose their leaves. When the temperature is lower than 10℃, the top blade will wither and droop. 2. The light is too strong. Strong direct light in summer will not only make the leaves pale, but also lead to falling leaves. 3. The soil in the basin is too dry. Changing trees to avoid drought requires a lot of water, so watering should be based on the principle of wet rather than dry. Once the soil in the basin is dry, plants often lose their leaves due to lack of water. In addition, we should pay attention to spraying water on the leaves and the surrounding ground frequently to moisten the environment afterwards. 4, not timely plastic pruning. People often do not pay attention to the pruning and pruning of flowers. In fact, pruning is very important for most flowers, and the plants after pruning will be more lush. 5. Improper fertilization. Nitrogen-containing substances should be applied more during the vigorous growth period. In view of the above reasons, corresponding measures can be taken to prevent deciduous trees from falling.