A Hypothesis Relating Current Annual Height Increment to Juvenile Wood Formation in Norway Spruce

Bohumil Kučera


The relationship between current annual height increment and anatomical and physical wood properties was studied on material from two spacing experiments in Norway spruce [Picea abies (L.) Karst.] on good sites in southeastern Norway. The two experimental plots were clearfelled for wood analysis at 52 and 79 years of age, respectively.

The first experiment comprised three spacings (1.25 × 1.25, 1.75 × 1.75, and 2.25 × 2.25 m), but differences in stand density had been evened out by thinnings at an early stage. No significant relationship between basic wood density and initial spacing was found here. The second experiment comprised one spacing (5.5 × 3.0 m).

Current annual height increment culminated at the age of 18-19 years in the first experiment and at 28-29 years in the second experiment. In both experiments, a transition phase between formation of the juvenile wood and the mature wood at the stump height level (root-neck) clearly coincided with culmination of the current annual height increment.

This supports a synchronous growth hypothesis, which states that the formation of mature wood in the stump height area (root-neck) commences when the current annual height increment has culminated.


Juvenile wood;height increment;anatomical and physical properties;synchronous growth hypothesis

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