Seed maturation of Scots pine and Norway spruce in a provenance experiment at Kortkeros (northern Russia) was examined by the X-ray method. Logarithmic relationships were found bt tween seed anatomy development and long-term average thermal sum. Seed development in the northern populations of Scots pine and Norway spruce was a little faster than in the southern ones.
Fedorkov, A
Climatic adaptation of seed maturity in Scots pine and Norway spruce populations
Silva Fennica