Termites that harm trees mainly include black-winged soil termites, yellow-winged termites, Taiwan milk termites, black-breasted termites, yellow-breasted termites and pointed-lipped termites. Different kinds of termites do different harm to trees. Lactic termites in Taiwan Province mainly eat xylem, so the damage found on the surface of trees is less, but it is very harmful to trees, and their nests are often built on some trunks or roots. Black-winged termites and yellow-winged termites generally harm the epidermis and cork layer of the trunk first, and then gradually penetrate into the xylem in the later stage. Generally speaking, yellow-winged termites eat deeper than black-winged termites. Reticulitermes flavipectus generally damages the superficial woody layer of epidermis, but it can also penetrate into the xylem in the later stage. Preventive measures for tree termites are: 1) quarantine. In the process of tree migration, termites are often inadvertently brought over, which makes them spread, so when transplanting trees, on the one hand, we should pay attention to thoroughly treating the remaining active termites before planting; On the other hand, don't choose trees that are seriously damaged by termites, especially those with nests of Taiwan's milk termites, so as to avoid the spread of ants. 2) Eliminate winged adults and prevent the emergence of new populations. The winged adults in the colony are the creators of the new colony. They fly and reproduce from April to July every year. In the meantime, they can use phototaxis to set lights for trapping and killing. 3) Protect natural enemies. 4) Eliminate the breeding ground of garden termites. There are often some dead trees, dead roots, stumps and sticks exposed to the open air for a long time in the garden, which are easy to rot after being wetted, and become the favorite materials of termites, which have a certain attraction to termites and must be removed. 5) Avoid mechanical damage to trees. Wound is the main entrance of termites, so in pruning, shaping and other operations, avoid causing big wounds, and do not cause mechanical damage in human activities such as intertillage and soil preparation. The wound that has been formed should be coated with anti-ant drugs first, and then with cedar oil to protect it. 6) Block the hole and repair the wound. Some big trees will have cavities or big wounds, so it is necessary to brush anti-ant drugs in time, and then block them with cement gravel or repair them with cement mortar, which is both beautiful and can prevent termites from invading. 7) chemical treatment. Using 10 diluted 50% chlordane emulsion solution or 9202 (Lesburn mixed solution) around the near-ground part of trees can prevent the harm of black-winged soil termites to climbing trees. In addition, ditching between seedlings and spraying 2% chlordane powder have certain effects on preventing cutting wood from being harmed by termites.