Logs are one of the first and most important materials you will come across in TerraFirmaCraft. Like in vanilla Minecraft, they are acquired by chopping down trees using an axe. Differing from Minecraft, however, chopping a tree in TFC will break all blocks above the chopped block, as well as destroying all connecting leaves (the main source of sticks in TFC). This consumes the equivalent amount of durability on your axe, as if you had chopped each individual block. Log-blocks in a tree will sometimes yield 2 log items per block of that tree type. Logs can thereafter be used for construction, crafting, or as fuel in firepits.
Placing the log on the ground for construction works the same way as in Minecraft. This log-block differs from the one in the tree, and will not produce 2 log-items if broken again, nor will it break log-blocks above it.
Rather than placing the logs for construction you can create log piles, for storage, by shift-clicking where you want the pile to be. You can construct a building out of log piles but you need a full 16 logs in each pile before you can place another on top of it, making this option quite expensive. (Exploit: Once you've placed a log pile on a fill 16-log block, you can remove all but 15 of the logs from the lower pile and put them into the top one.)
To make lumber (plank items), you must now combine them with a saw in the crafting box, yielding 8 lumber from one log.
Bowls can be made by combining a knife and a log in the crafting box, yielding 4 bowls for each log, and consuming a slight amount of durability on the knife.
Logs are also used to create support beams, to prevent cave-ins. Place two logs in either vertical or horizontal fashion in the crafting box along with a saw to produce 8 vertical or horizontal support beams respectively.