The existence of a market for certified greenhouse gases emission reductions creates a new variable to take into account in economical valuation of forest enterprises: the CO2 absorption. The sequestration of this gas generates a dividend flow which becomes an extra revenue, having influence in the managerial decisions taken by the forest manager. This work studies the effects caused by this influence over the optimal rotation age of the stand. The forest studied is an Eucalyptus stand, explored due to its timber and whose growth curve is known. The stumpage price varies stochastically and cannot be predicted, while a certificate corresponding to one ton of sequestered CO2 is traded in a specific market at a price considered constant and exogenous. All the other parameters involved are constant and know. Facing the uncertain stumpage market price, the manager can make three possible decisions: to harvest, wait or abandon. Due to the characteristics of this kind of activity, the Real Options Theory has shown to be the most suitable to be used in this case.