© 1990 Heron Publishing—Victoria, Canada
Inherited narrow crown form, harvest index and stem biomass production in Norway spruce, Picea abies
P. Pulkkinen and T. Pöykkö
Foundation for Forest Tree Breeding, Viljatie 4 A 5, 00700 Helsinki, Finland / Received November 9, 1989
Summary
The effect of crown form on stem biomass production was investigated in an 18–19-year-old Norway spruce stand (Picea abies (L.) Karst.). The harvest index was 0.271 in pendula trees, which have a heritable narrow crown form, and 0.235 in normal-crowned
trees and the dry weights of stem biomass
were 2.57 kg and 3.37 kg, respectively. However, the production of stem biomass per crown projected area was more than twice
as much in pendula trees as in normal-crowned trees. Results indicate that the crown form of pendula spruce is less plastic
than that of normal-crowned spruce suggesting that such trees might maintain a high stemwood yield per unit ground area with
increasing stand density. Because pendula spruce has a higher harvest index and a less flexible crown than normal-crowned
spruce, it might be useful for crop tree ideotype breeding.
