I CANT UPGRADE the middle wood frame block ??? (with pictures)

[7daysOfFun]

i want this small middle wood block, i cant upgrade it...

iv choosen in metal , in stone , in wood..its only in the wood sortiment and i cant upgrade him...so i must choose another block..

see pictures

 

[Laz Man]

What POI is that?

 

[7daysOfFun]

i think its the water factory...left in background behind me is the high tower