An upper stem diameter measurement and basal area determination device for timber cruising operations incorporates a viewing window in which are projected variable, visual brackets for manual alignment by the user, or automatic setting under processor section control, with the left and right sides of a target tree stem or trunk. The invention is characterized in that the switch is switched by the lift mechanism. The first silicon nitride layers and the first silicon oxide layers are stacked alternately. per cm2 of the positive electrode, and B is an available electric capacity at 25\xb0 C. Snap-on connectors interconnect the attachment members and the connector receivers.