An Island Spruce Log is a type of crafting material in FFXIV. It’s currently exclusive to Island Sanctuary and, more specifically, foraging expeditions performed after building your first Granary. For this reason, the material doesn’t appear in the Island Gathering Log and is mostly used in the production of certain Handicrafts, as well as some building upgrades. Such as the Granary III renovation.
Instead of gathering it manually, you can acquire Island Spruce Logs by building a Granary (or two) and then speaking to the Excitable Explorer NPC. This is a mammet found in the center of the Home Sweet Hideaway zone. Select “Wild Woods” from the list of available Expedition Areas. The log will appear on the far-right side of the menu — under the Rare Resources square.
You can collect your expedition rewards from the Excitable Explorer after a specified time once per real-world day after putting in an order.