Use trees as structural beams of smaller buildings?. Grow your house? Perhaps better to plant vines & shrubs on window sills. Trees on roof? Lots of "green buildings" "out there". Harvest the biomass annually. Dry it, & carbonize the residue. Use the derived charcoal in water purification sewage plants. When spent carbon residue is spread on land, it is useful soil conditioner, particularly if combined with phosphate reclamation residues also from sewage plants.

Kenneth - surely biochar is sequestered permanently? If the crop residues, particularly if augmented by phosphate sludge, are added back to the land, then the biochar will not biodegrade? see "Terra Preta del Indio". Simple & effective, just like the Icelandic route hydrolysing basalt to make clay & chalk?. Another way of sequestering C is to build your structures of wood or compressed straw. Kind of like the structures built by African acacia trees to attract ant colonies,