At present,the altimeter commonly used in field survey can be divided into two types:mechanical/optical and electronical altimeter.The mechanical/optical altimeter has a simple structure and there is a large reading error.The laser range finder is mainly based on the distance measurement and the error of the height measurement is large.The ultrasonic altimeter uses ultrasound waves to complete the distance measurement,and then the angle data is used to calculate the height of the tree.The device is divided into two parts:the main body and the reflector.Therefore,the measurement process is complicated.The new portable tree altimeter has a built-in temperature compensated MEMS tilt sensor and phase laser ranging.It is also equipped with a holographic laser sight.The tree altimeter is intelligent,precise,portable and easy to use.Through comparison with laser range finder and ultrasonic altimeter,the accuracy of the height measurement by the tree altimeter is basically the same as that of the ultrasonic altimeter,but it is better than the laser range finder; the accuracy of the distance measurement by the tree altimeter is basically the same as that of the laser range finder,but it is better than the ultrasonic altimeter.