This study examined how a common forest fungus (Paxillus involutus) responds to cold temperatures by analyzing its chemical composition. When kept at cold temperatures like those found in spring and autumn forests, the fungus took up and used more nitrogen for making amino acids and other nitrogen compounds, even though it grew more slowly. This suggests that cold-adapted fungi have special mechanisms to acquire nutrients efficiently in cold conditions, which may be important for how they help trees survive in changing climates.