The Mushroom Log produces mushrooms every 4 days, rainy days will cause this to take a day less.
The quantity of mushrooms produced increases with the amount of wild trees in the 7X7 square around the log. The amount of mushrooms generated, limited to between 1 and 5, is calculated by finding the number of nearby trees and multiplying this by a random number between 0.5 and 1.5.[1] Therefore, the number of nearby trees needed to always gain the maximum amount of 5 is 10.
The type of mushroom produced depends on what tree types are nearby it. The game code creates a possible list of mushrooms based on nearby trees then selects one at random from that list.
- First the game finds how many trees are in the 7X7 square around it. That number is multiplied by 3/4 and that many mushrooms are added to the list with a distribution of 5% purple, 14.25% red and 80.75% common.
- Then, for each fully grown tree another mushroom will be added. If the tree type is Oak Tree then the mushroom added will always be a Morel. The same goes for Pine Tree with Chanterelle, and for Mystic Tree with Purple Mushroom. Maple trees have a 10% chance to give Purple Mushroom and a 90% chance to give Red Mushroom. If it is none of those types it will use the same distribution as before.
- Then a random mushroom is chosen from that list to generate.[1]
The produced mushrooms can have different qualities but are unaffected by the Botanist Perk. The quality is instead calculated based on the number of nearby trees, and how many of them have moss on them. Every nearby tree is counted, with mossy counting as double. This number is then divided by 40 and is used as the chance for the quality to upgrade. This chance occurs repeatedly until it fails or reaches iridium quality. So for example if the count is 20 then the chance is 0.5, meaning there is a 50% chance of regular quality, a 25% chance of silver quality, 12.5% chance of gold quality, and a 12.5% chance of iridium quality. If the count is 40, 5 mushrooms of iridium quality is guaranteed.