Abstract
Context
Taper equations predict the variation in diameter along the stem, therefore characterizing stem form. Several recent studies have tested mixed models for developing taper equations. Mixed-effects modeling allow the interindividual variation to be explained by considering both fixed-effects parameters (common to the population) and random-effects parameters (specific to each individual).
Aims
The objective of this study is to develop a mixed-effect variable exponent taper equation for birch trees in northwestern Spain by determining which fixed-effects parameters should be expanded with random-effects parameters.
Methods
All possible combinations of linear expansions with random effects in one and in two of the fixed-effects model parameters were tested. Upper stem diameter measurements were used to estimate random-effects parameters by the use of an approximate Bayesian estimator, which calibrated stem profile curves for individual trees.
Results
Parameter estimates for more than half of the mixed models investigated were nonsignificant. A first order autoregressive error structure was used to completely remove the autocorrelation between residuals, as mixed-effects modeling were not sufficient for this purpose.
Conclusion
The mixed model with the best fitting statistics did not provide the best calibration statistics for all upper stem diameter measurements. From a practical point of view, model calibration should be considered an essential criterion in mixed model selection.
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References
Adu-Bredu S, Bi AFT, Bouillet JP, Mé MK, Kyei SY, Saint-André L (2008) An explicit stem profile model for forked and unforked teak (Tectona grandis) trees in West Africa. For Ecol Manage 255:2189–2203
Avery TE, Burkhart HE (2002) Forest measurements, 5th edn. McGraw-Hill, New York
Bi HQ (2000) Trigonometric variable-form taper equations for Australian eucalyptus. For Sci 46:397–409
Bruce D, Curtis RO, Vancoevering C (1968) Development of a system of taper and volume tables for red alder. For Sci 14:339–350
Burkhart HE (1977) Cubic-foot volume of loblolly pine to any merchantable top limit. South J Appl For 1:7–9
Burkhart HE, Walton SB (1985) Incorporating crown ratio into taper equations for loblolly pine trees. For Sci 31:478–484
Cao QV, Burkhart HE (1980) Cubic foot volume of loblolly pine to any height limit. South J Appl For 4:166–168
Cao QV, Burkhart HE, Max TA (1980) Evaluation of two methods for cubic–volume prediction of loblolly pine to any merchantable limit. For Sci 26:71–80
Castroviejo S, Laínz M, López González G, Monteserrat P, Muñoz Garmendia F, Paiva J, Villar L (1990) Flora ibérica: Plantas vasculares de la Península Ibérica e Islas Baleares. Volumen II: Platanaceae-Plumbaginaceae (partim.). RJB (CSIC), Madrid
Clutter JL, Fortson JC, Pienaar LV, Brister GH, Bailey RL (1983) Timber management: a quantitative approach. Krieger Publishing Company, New York
Cochran WG (1963) Sampling techniques, 2nd edn. Wiley, New York
Corral-Rivas JJ, Diéguez-Aranda U, Corral Rivas S, Castedo Dorado F (2007) A merchantable volume system for major pine species in El Salto, Durango (Mexico). For Ecol Manage 238:118–129
Davidian M, Giltinan DM (1993) Some general estimation methods for nonlinear mixed-effects models. J Biopharm Stat 3:23–55
Davidian M, Giltinan DM (1995) Nonlinear models for repeated measurement data. Chapman & Hall, New York
DGCONA (2002) Tercer Inventario Forestal Nacional, 1997–2006: Galicia. Dirección General de Conservación de la Naturaleza. Ministerio de Medio Ambiente, Madrid
Diéguez-Aranda U, Castedo-Dorado F, Álvarez-González JG, Rojo A (2006) Compatible taper function for Scots pine plantations in northwestern Spain. Can J For Res 36:1190–1205
Fang Z, Bailey RL (2001) Nonlinear mixed-effects modeling for slash pine dominant height growth following intensive silvicultural treatments. For Sci 47:287–300
Fang Z, Borders BE, Bailey RL (2000) Compatible volume-taper models for loblolly and slash pine based on a system with segmented-stem form factors. For Sci 46:1–12
Fonweban J, Gardiner B, Macdonald E, Auty D (2011) Taper functions for Scots pine (Pinus sylvestris L.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) in Northern Britain. Forestry 84:49–60
Garber SM, Maguire DA (2003) Modeling stem taper of three central Oregon species using nonlinear mixed effects models and autoregressive error structures. For Ecol Manage 179:507–522
Goulding CJ, Murray JC (1976) Polynomial taper equations that are compatible with tree volume equations. N Z J For Sci 5:313–322
Gregoire TG, Schabenberger O, Kong F (2000) Prediction from an integrated regression equation: a forestry application. Biometrics 56:414–419
Hann DW, Walters DK, Scrivani JA (1987) Incorporating crown ratio into prediction equations for Douglas-fir stem volume. Can J For Res 17:17–22
Hartford A, Davidian M (2000) Consequences of misspecifying assumptions in nonlinear mixed effects models. Comput Stat Data Anal 34:139–164
ICONA (1993) Segundo Inventario Forestal Nacional. Ministerio de Agricultura, Pesca y Alimentación, Madrid
Jones RH (1990) Serial correlation or random subject effects? Commun Stat Simul Comput 19:1105–1123
Kozak A (1988) A variable–exponent taper equation. Can J For Res 18:1363–1368
Kozak A (2004) My last words on taper functions. For Chron 80:507–515
Kozak A, Munro DD, Smith JHG (1969) Taper functions and their application in forest inventory. For Chron 45:278–283
Laird NM, Ware JH (1982) Random-effects models for longitudinal data. Biometrics 38:963–974
Leites LP, Robinson AP (2004) Improving taper equations of loblolly pine with crown dimensions in a mixed-effects modeling framework. For Sci 50:204–212
Lindstrom MJ, Bates DM (1990) Nonlinear mixed-effects models for repeated measures data. Biometrics 46:673–687
Littell RC, Milliken GA, Stroup WW, Wolfinger RD, Schabenberger O (2006) SAS for mixed models, 2nd edn. SAS Institute Inc., Cary, NC
Max TA, Burkhart HE (1976) Segmented polynomial regression applied to taper equations. For Sci 22:283–289
Muhairwe CK (1999) Taper equations for Eucalyptus pilularis and Eucalyptus grandis for the north coast in New South Wales, Australia. For Ecol Manage 113:251–269
Muhairwe CK, LeMay VM, Kozak A (1994) Effects of adding tree, stand, and site variables to Kozak's variable–exponent taper equation. Can J For Res 24:252–259
Newnham RM (1988) A variable-form taper function. Information Report PI-X-83. Petawawa National Forest Institute. Canadian Forest Service, Petawawa, Ontario, Canada
Newnham RM (1992) Variable-form taper functions for four Alberta tree species. Can J For Res 22:210–223
Pérez D, Burkhart HE, Stiff C (1990) A variable-form taper function for Pinus oocarpa Schiede. in Central Honduras. For Sci 36:186–191
Pinheiro JC, Bates DM (1995) Approximations to the log-likelihood function in the nonlinear mixed effects model. J Comput Graph Stat 4:12–35
Pinheiro JC, Bates DM (2000) Mixed-effects models in S and S-PLUS. Springer, New York
SAS support (2011) Sample 25032: %NLINMIX macro to fit nonlinear mixed models. http://support.sas.com/kb/25/032.html. Accessed 7 July 2011
Tasissa G, Burkhart HE (1998) An application of mixed effects analysis to modeling thinning effects on stem profile of loblolly pine. For Ecol Manage 103:87–101
Trincado G, Burkhart HE (2006) A generalized approach for modeling and localizing stem profile curves. For Sci 52:670–682
Valentine HT, Gregoire TG (2001) A switching model of bole taper. Can J For Res 31:1400–1409
VanderSchaaf CL, Burkhart HE (2007) Comparison of methods to estimate Reineke's maximum size–density relationship species boundary line slope. For Sci 53:435–442
Vonesh EF (1996) A note on the use of Laplace's approximation for nonlinear mixed effects models. Biometrika 83:447–452
Vonesh EF, Chinchilli VM (1997) Linear and nonlinear models for the analysis of repeated measurements. Marcel Dekker Inc, New York
West PW, Ratkowsky DA, Davis AW (1984) Problems of hypothesis testing of regressions with multiple measurements from individual sampling units. For Ecol Manage 7:207–224
Wolfinger RD, Lin X (1997) Two Taylor-series approximation methods for nonlinear mixed models. Comput Stat Data Anal 25:465–490
Xunta de G (2001) O monte galego en cifras. Dirección Xeral de Montes e Medio Ambiente Natural. Consellería de Medio Ambiente. Santiago de Compostela (Spain)
Yang Y, Huang S, Trincado G, Meng SX (2009) Nonlinear mixed-effects modeling of variable–exponent taper equations for lodgepole pine in Alberta, Canada. Eur J For Res 128:415–429
Funding
The present study was financially supported by the Spanish Ministry of Education and Science through the research project Modelos de evolución de bosques de frondosas caducifolias del noroeste peninsular (AGL2007-66739-C02-01/FOR), co-funded by the European Union through the European Regional Development Fund.
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Handling Editor: Barry Alan Gardiner
Contribution of the co-authors
Esteban Gómez-García and Ulises Diéguez-Aranda analyzed the data and wrote the manuscript. Felipe Crecente-Campo provided technical assistance in model fitting and revised the text.
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Gómez-García, E., Crecente-Campo, F. & Diéguez-Aranda, U. Selection of mixed-effects parameters in a variable–exponent taper equation for birch trees in northwestern Spain. Annals of Forest Science 70, 707–715 (2013). https://doi.org/10.1007/s13595-013-0313-9
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DOI: https://doi.org/10.1007/s13595-013-0313-9