Once you start exploring outside of the Grasslands in LEGO Fortnite, you will notice that some materials are tougher to harvest, such as the wood found inside caves. However, bringing the right tool for the job will get rid of any issues you have in collecting resources.
LEGO Fortnite: How to Cut the Wood in Caves
To collect the wood from caves, you need to have an uncommon rarity Forest Axe or higher. The color of your axe can tell you exactly what rarity you currently have. Green items are uncommon and grey are considered common. Any other rarity in LEGO Fortnite is above green. So as long as the axe isn’t grey, it can cut down the wood in caves.