Full text of this article is only available in PDF format.

Jouni Siipilehto (email)

Improving the accuracy of predicted basal-area diameter distribution in advanced stands by determining stem number

Siipilehto J. (1999). Improving the accuracy of predicted basal-area diameter distribution in advanced stands by determining stem number. Silva Fennica vol. 33 no. 4 article id 650. https://doi.org/10.14214/sf.650


The objective of this paper was to study to what extent the accuracy of predicted basal-area diameter distributions (DDG) could be improved by means of stem number observations in advanced (H > 10 m) stands. In the Finnish forest management planning (FMP) inventory practice, stem number is determined only in young stands; in older stands stand basal area is used. The study material consisted of sixty stands of Norway spruce (Picea abies Karst.) and ninety-one stands of Scots pine (Pinus sylvestris L.) with birch (Betula pendula Roth and B. pubescens Ehrh.) admixtures in southern and eastern Finland. For test data, 167–292 independent, National Forest Inventory-based, permanent sample plots were used. DDGs were estimated with the maximum likelihood method. Species-specific models for predicting the distribution parameters were derived using regression analysis. The two-parameter Weibull distribution was compared to the three-parameter Johnson’s SB distributions in predicting DDGs. The models were based on either predictors that are consistent with current FMP (model G), or assuming an additional stem number observation (model G+N). The predicted distributions were compared in terms of the derived stand variables: stem number, total and timber volumes. The results were similar in modelling and test data sets. Methods, based on the SB distribution obtained with model (G+N), proved to give the most accurate description of the stand structure. Differences were marginal in stand total volumes. However, the error variation in stem number was 20% to 80% lower than when applying model (G). SB and Weibull distributions gave very much the same results if model (G) was applied.

dbh distribution; parameter prediction; Johnson’s SB distribution; Weibull distribution

Author Info
  • Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail jouni.siipilehto@metla.fi (email)

Received 29 March 1999 Accepted 4 October 1999 Published 31 December 1999

Views 615

Available at https://doi.org/10.14214/sf.650 | Download PDF

Creative Commons License

Click this link to register to Silva Fennica.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content

Your selected articles
Your search results
Siipilehto J., Lyly O. (1995) Weed control trials with fibre mulch, glyphosate.. Silva Fennica vol. 29 no. 1 article id 5545
Lee D., Siipilehto J. et al. (2021) Models for diameter distribution and tree height.. Silva Fennica vol. 55 no. 5 article id 10612
Siipilehto J., Mäkinen H. et al. (2021) Models for integrating and identifying the effec.. Silva Fennica vol. 55 no. 2 article id 10496
Siipilehto J., Allen M. et al. (2020) Stand-level mortality models for Nordic boreal f.. Silva Fennica vol. 54 no. 5 article id 10414
Siipilehto J., Rajala M. (2019) Model for diameter distribution from assortments.. Silva Fennica vol. 53 no. 1 article id 10062
Siipilehto J., Lindeman H. et al. (2016) Reliability of the predicted stand structure for.. Silva Fennica vol. 50 no. 3 article id 1568
Siipilehto J., Mehtätalo L. (2013) Parameter recovery vs. parameter prediction for .. Silva Fennica vol. 47 no. 4 article id 1057
Siipilehto J., (2011) Local prediction of stand structure using linear.. Silva Fennica vol. 45 no. 4 article id 99
Siipilehto J., Sarkkola S. et al. (2007) Comparing regression estimation techniques when .. Silva Fennica vol. 41 no. 2 article id 300
Siipilehto J., (2006) Linear prediction application for modelling the .. Silva Fennica vol. 40 no. 3 article id 334
Siipilehto J., (2006) Height distributions of Scots pine sapling stand.. Silva Fennica vol. 40 no. 3 article id 331
Siipilehto J., Siitonen J. (2004) Degree of previous cutting in explaining the dif.. Silva Fennica vol. 38 no. 4 article id 410
Siipilehto J., (2001) Effect of weed control with fibre mulches and he.. Silva Fennica vol. 35 no. 4 article id 577
Siipilehto J., (2000) A comparison of two parameter prediction methods.. Silva Fennica vol. 34 no. 4 article id 617
Siipilehto J., (1999) Improving the accuracy of predicted basal-area d.. Silva Fennica vol. 33 no. 4 article id 650