Guck is found in the Swamp in glowing green clumps attached to large trees. To gather guck you will need to climb the tree because you cannot cut down guck-covered trees. Be careful of low-hanging guck because there are usually leeches in the water with deadly poison.
Guck-covered trees are the only trees in Valheim that cannot be chopped down.
Guck is needed for all green aesthetic structures but most importantly for the Draugr Fang Bow.
We recommend bringing your own wood to the swamp when you are guck farming because the Ancient Trees are not great for gathering wood.
You will need to build a workbench near the base of the tree which might also require leveling off the ground with a hoe. After that, there’s not really a strategy for building scaffolding to climb guck-covered trees, but here’s a look at how I used a bunch of ladders to reach every deposit:
Gallery
Mining guck 
Scaffolding to climb a guck-covered tree.
