RELATION BETWEEN LEAF BIOMASS AND ANNUAL RING SAPWOOD OF NORWAY SPRUCE ACCORDING TO NEEDLE AGE-CLASS

The relationship between leaf biomass and sapwood area was investigate d in a 35-year-old Norway spruce (Picea abies (L.) Karst.) stand in mo untainous conditions. Fifteen trees were destructively sampled to dete rmine the needle biomass in several needle age-classes and whorls and the corresponding sapwood areas at the whorl branch bases and in stems at breast height. Leaf biomass/sapwood area ratio and specific leaf b iomass (g . mm(-2)) were calculated for different needle age-classes a nd also for different positions in the vertical profile of the crown. The leaf biomass/sapwood area ratios were described by linear regressi on with a high coefficient of determination. Specific leaf biomass ana lysed in whorl branches was highest in the upper whorls but was decrea sing downward through the profile; remained stable in the middle crown layer; and decreased again in the lower crown parts. Specific leaf bi omass assessments for stems showed the largest and most increasing val ues in the youngest three needle age-classes followed by a decreasing trend of the specific leaf biomass in older needle age-classes. The me an values of specific leaf biomass were 1.08 g . mm(-2) for branches a nd 1.02 g . mm(-2) for stems. The results of our study are consistent with the ''pipe model theory.''