Seven sample trees of Norway spruce of different social position were chosen for analysis of needle biomass distribution in the crown profile in a 19-year-old stand. Vertical needle dry mass distribution was approximated with a one-peak-curve according to equation Q = A . exp [– B . (h0.5 – C )2]. Crown zone with the maximum of needle dry mass did not exceeded 70% of the tree relative height. In individual groups of subdominant, co-dominant, and dominant sample trees these zones reached 24, 33 and 42% of the tree relative height respectively. The total amount of needle dry mass of the whole stand was 2.624 kg.m-2 with a maximum ca 3 m above the soil surface. A spatial stationary network containing 48 sensors in four levels was installed for evaluating the effect of the stand vertical structure to its radiation regime. Parameters of exponential profile of radiation intensity were figured out for the individual sun elevation angles (h°) in the range between 20 and 65 degrees. The radiation intensity I6,2 m in clear days increased proportionally with the Sun elevation angle for 20° < h° < 40°, and was independent of h° for the angles above 40°. The intensity I increased mostly proportionally with h° up to its maximum (63°) for the level 1.5¸3.75 m above the soil surface. The penetration of radiation through the canopy in cloudy days was completely independent on the sun elevation angle. Concerning the biomass distribution, only 3 to 10% of the radiation income reached the level with the minimum of needle dry mass in dependence on the elevation angle. On the other hand, the irradiation dropped to its half at the height corresponding to ca 90% of the total needle dry mass, 50% of solar energy were absorbed by the highest 10% of needle biomass.