... without destruction of trees normal growth, it can identify trees growth rate, age of the trees, trees growth hardness degree and nutrients migration.CharacteristicAdopt ... rotation, and get wood core within core extractor. Tree growth condition can be analysed by watching wood core color distribution.CompositionSleeve, ... extractor: d=5mmDrill pipe length: 20cm, 25cm, 30cm, 35cm, 40cm Plant Growth Awl