Biomass and structure of Norway spruce trees grown in uneven-aged stands in southern Finland

ABSTRACT

Tree biomass models are increasingly needed for the estimation of carbon storage and for testing and parameterizing process-based growth models, but most biomass models have been estimated using data from even-aged stands. Here we took measurements from individual Norway spruce trees grown in uneven-aged stands in Southern Finland to characterize tree structure and to estimate the biomasses of tree components. Using the data, we tested various structural biomass equations developed for even-aged stands for their suitability to uneven-aged stands. The test trees had longer crowns than usually found in an even-aged Norway spruce stand, ranging from 55 to 85% of total tree height. The average proportion of total biomass in branches and foliage was 13.8 % and 7.0 %, respectively. The average wood density of the test trees was slightly higher than that reported for Norway spruce trees of comparable size. The structural relationships found in trees under even-aged management were applicable to trees growing in uneven-aged stands but required re-parameterization. In particular, the trees had higher branch and stem biomass than trees of same stem and crown dimensions on average in even-aged stands. The relationship of crown ratio and the slenderness index on an uneven-aged stands also differed from those reported in even-aged stands.

KEYWORDS:

• Uneven-aged structure
• Norway spruce
• biomass model
• structural model

Acknowledgements

We would like to thank Sauli Valkonen for providing comments and suggestions for this study and Markku Rantala for the site information.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding for this study was provided by the Maj and Tor Nessling foundation (Maj ja Tor Nesslingin Säätiö), by [EU FP7], [grant number 311970] (FORMIT) and IBC-CARBON Academy of Finland Strategic Council project number [312559].