Answer 4 :: "sequential"

Tree embodies development in time & has "archival" function.

Answer 3 :: "functional"

Functional morphisms (upwards & downwards "flow", "bifurcations", "supply" )

Answer 2 :: "structural"

Structural morphisms (roots, branches etc.)

Answer 1 :: "conceptual"

Both organic and digital trees are human concepts (results of activity of analytical Mind).

Answer0 :: "partitioning"

Both organic and digital trees divide "the space" into partitions.

Coded in vim (front-end: D3.js; back-end: kastalia.medienhaus) by Prof. Daniel D. Hromada (UdK / ECDF).