The aim of the study was to asses the plough effects in the above and below ground biomass Eucalyptus globulus plantations. At the same time the root damage was evaluated. The project was carried out in two experimental stands, three trees were chosen by stand and plought treatment. The above ground biomass was determining harvesting the tree. The coarse and fine root were evaluated in 3.6 and 0.688 m3 of soil volume, respectively. Furthermore the root damage were analized in 50 trees. Afterward the predawn leaf water potential were determining in plough and unplough trees. The total above ground biomass have not statistical differences between treatments. The coarse roots represent a high percentage of the below ground biomass and the fine root biomass is higher near the stump. The plough effect was concentrated within the 0-20 cm soil profile. In the plough assay the amount of fine root was higher in the undisturbed than in ploughed soil. Greater part of more superficial fine roots were cuted and linearly decrease the predawn leaf water potential when increase the root damage.