Summary For spruce trees ( Picea abies (L.) Karst.) in the Northern Black Forest, the chlorophylla and the total carotene content of the needles go through seasonal changes with maximum in summer and minimum in winter. Variations of the carotene content are mainly due to pronounced changes of α-carotene while β-carotene varies only slightly. The following observations suggest that both, temperature and light intensity control the α-carotene level: In a constant climate of high temperature and low light a high α-carotene level is maintained. Under field conditions α-carotene accumulates at average monthly temperatures over 13 °C. The α-/β-carotene ratio is slightly enhanced in shaded as compared to sun-exposed needles and increases significantly when the chlorophyll content of the needles is increased. Therefore, α-carotene accumulation is favoured by low light reaching the thylakoids, as in case of low external photon flux density or internal shading from other thylakoids.