A saw chain guide bar comprising: - an elongated guide bar body, which has a rear end and an opposite nose end, wherein the guide bar body at its rear end has an attachment section configured for attachment to a chainsaw cutting device of a tree harvester and wherein the guide bar body has a first side face extending between the rear end and the nose end and an opposite second side face extending between the rear end and the nose end; and - a liquid feed channel extending along a part of the guide bar body from the attachment section towards the nose end, the liquid feed channel having an upstream end located at the attachment section and a downstream end located at a distance from the attachment section, wherein the liquid feed channel at its upstream end has an inlet opening, through which the liquid feed channel is configured to receive pressurized liquid, characterized in: - that the liquid feed channel at its downstream end has a first outlet with at least one first spray outlet orifice facing the nose end or the rear end of the guide bar body, wherein this first outlet is in fluid communication with the inlet opening and configured to emit liquid received therefrom as a liquid spray through said at least one first spray outlet orifice in a direction towards the nose end of the guide bar body if said at least one first spray outlet orifice faces the nose end or in a direction towards the rear end of the guide bar body if said at least one first spray outlet orifice faces the rear end; and - that the guide bar body is provided with a first spray guiding groove formed as an outwardly open elongated recess in the first side face of the guide bar body, wherein said at least one first spray outlet orifice opens into the first spray guiding groove and the first spray guiding groove extends from said first outlet of the liquid feed channel in a direction towards the nose end of the guide bar body if said at least one first spray outlet orifice faces the nose end or in a direction towards the rear end of the guide bar body if said at least one first spray outlet orifice faces the rear end. - an elongated guide bar body, which has a rear end and an opposite nose end, wherein the guide bar body at its rear end has an attachment section configured for attachment to a chainsaw cutting device of a tree harvester and wherein the guide bar body has a first side face extending between the rear end and the nose end and an opposite second side face extending between the rear end and the nose end; and - a liquid feed channel extending along a part of the guide bar body from the attachment section towards the nose end, the liquid feed channel having an upstream end located at the attachment section and a downstream end located at a distance from the attachment section, wherein the liquid feed channel at its upstream end has an inlet opening, through which the liquid feed channel is configured to receive pressurized liquid, - that the liquid feed channel at its downstream end has a first outlet with at least one first spray outlet orifice facing the nose end or the rear end of the guide bar body, wherein this first outlet is in fluid communication with the inlet opening and configured to emit liquid received therefrom as a liquid spray through said at least one first spray outlet orifice in a direction towards the nose end of the guide bar body if said at least one first spray outlet orifice faces the nose end or in a direction towards the rear end of the guide bar body if said at least one first spray outlet orifice faces the rear end; and - that the guide bar body is provided with a first spray guiding groove formed as an outwardly open elongated recess in the first side face of the guide bar body, wherein said at least one first spray outlet orifice opens into the first spray guiding groove and the first spray guiding groove extends from said first outlet of the liquid feed channel in a direction towards the nose end of the guide bar body if said at least one first spray outlet orifice faces the nose end or in a direction towards the rear end of the guide bar body if said at least one first spray outlet orifice faces the rear end.