1:17a

The beams of our house are cedars:
This clause continues the figurative description of the couple’s forest house. The trees surround the man and woman, providing protection and privacy. Some other ways to translate this clause are:

Branches of cedar trees are the “roof” of our house
-or-
Branches of cedar trees are like the roof of a house for us
-or-
Our roof is the sky, and the cedar trees are like its frame/supports

The beams: The word beams refers to large pieces of wood that support the roof of a house. In this context, the branches of the cedar trees are like these large pieces of wood in a house. The man and woman looked up at these branches of the trees, as though they were in a forest “house” looking up at the beams that support the roof.

cedars: The word “cedar” is a kind of evergreen tree that grows large and tall. Its wood is hard and smells sweet, and it is valuable for building.