1) Beam 2) Ridge 3) Rooftree 1) Rooftree 
• (n.) The timber forming the ridge of a roof, into which the rafters are secured.
(from the article `building construction`) ...the difficulties of cutting large trees with stone tools limited the use of sizable timbers to frames. These frames were usually rectangular in ...
Ridge'pole` noun (Architecture) The timber forming the ridge of a roof, into which the rafters are secured. 
In architecture, the ridgepole is the timber forming the ridge of a roof, into which the rafters are secured.