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Taper and volume equations for poplar trees growing on farmland in Sweden

Hjelm, Birger (2011). Taper and volume equations for poplar trees growing on farmland in Sweden. Uppsala : Sveriges lantbruksuniv. , Rapport (Institutionen för energi och teknik, SLU), 1654-9406 ; 029
ISBN 978-91-576-9035-7
[Licentiate thesis]

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Abstract

Effective management of poplar plantations for high yield production would be facilitated by the availability of improved equations for predicting the taper and volume of poplar stems. Therefore, this thesis is based upon a polynomial stem taper equation and two volume equations constructed for individual poplar trees growing on farmland. Data for fitting and evaluate the taper and volume equations were collected from 51 trees growing in 27 stands in central and southern Sweden (lat. 55-60° N). The mean age of the stands was 22 years, mean density 970 stems ha⁻¹, and mean diameter at breast height 24 cm. Validation data were collected from 17 trees growing in ten stands, not used for fitting the equations.

The outputs of the polynomial taper equation were compared with five published equations. The statistical evaluation indicated that the variable exponent taper equation presented by Kozak (1988) performed best and can be recommended. Because this equation´s complex construction, alternative recommendations were made. The constructed taper equation and the segmented equation presented by Max & Burkhart (1976) were second and third ranked.

The first constructed stem volume equation is a function of diameter at breast height (DBH) and total height (H) as independent variables. In addition to these variables the other is also a function of an upper diameter. The outputs of these two equations were analyzed and compared to those of five published equations developed for, or applied on, poplar or aspen species. Of the stem volume equations examined the best performance was provided by the constructed equation with an additional upper diameter and recommended when precise and accurate volume estimations are required. However, because of difficulties to measure diameters high above ground, this equation is less practical in traditional surveys. For this purpose, the first constructed equation or the equation developed by Fowler & Hussain 1987 can be recommended.

The taper and volume equations recommended in the study are likely to be useful in optimizing the efficiency and profitability of poplar plantation management.

Authors/Creators:Hjelm, Birger
Title:Taper and volume equations for poplar trees growing on farmland in Sweden
Series/Journal:Report (Department of Energy and Technology, SLU)
Year of publishing :2011
Volume:029
Number of Pages:47
Papers/manuscripts:
NumberReferences
I.Hjelm B. (2011). Stem Taper Equations for Poplars Growing on Farmland in Sweden. Submitted to Journal of Forestry Research
II.Hjelm B., Johansson T. (2011). Stem Volume Equations for Poplars Growing on Farmland in Sweden. Submitted to Scandinavian Journal of Forestry Research
Place of Publication:Uppsala
Publisher:Dept. of Energy and Technology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-9035-7
ISSN:1654-9406
Language:English
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
Subjects:Obsolete subject words > FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING > Plant production > Forestry
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:populus, stems, tree form, forest mensuration, height, diameter, farmland, models, sweden
Keywords:Poplar, Stem volume equation, Taper equation, Segmented taper equation, Variable exponent taper equation
URN:NBN:urn:nbn:se:slu:epsilon-e-70
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-70
ID Code:8020
Department:(NL, NJ) > Dept. of Energy and Technology
Deposited By: Birger Hjelm
Deposited On:29 Apr 2011 14:31
Metadata Last Modified:02 Dec 2014 10:45

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