@article{isik_mora_schimleck_2011, title={Genetic variation in Pinus taeda wood properties predicted using non-destructive techniques}, volume={68}, ISSN={1286-4560 1297-966X}, url={http://dx.doi.org/10.1007/s13595-011-0035-9}, DOI={10.1007/s13595-011-0035-9}, abstractNote={Tree breeders have been reluctant to include wood traits in tree improvement programs owing to logistic difficulties and the cost associated with the assessing the traits. We aimed to evaluate the efficiency of two non-destructive techniques for genetic parameters estimation in three diallel test series of loblolly pine (Pinus taeda L.). The traits were measured by acoustics (velocity, stiffness) and predicted by calibration models based on near infrared (NIR) spectra (air-dry density, microfibril angle, modulus of elasticity, coarseness, wall thickness). Acoustic and NIR-predicted traits were not correlated with diameter based on 30 full-sib family means of each diallel series. Correlations between traits were in accordance with previous published results. Additive genetic variation was considerable for all traits. Specific combining ability variances were not significant. The traits predicted by acoustic and NIR methods had high narrow-sense individual tree and family mean heritability values. Individual tree narrow sense heritability ranged from 0.14 (tracheid coarseness) to 0.92 (air-dry density). As expected, family mean heritability values of most traits exceeded 0.80. The high heritabilities suggest that acoustic and NIR-based methods can efficiently be used for screening loblolly pine progeny tests for surrogate wood traits. Such methods can save considerable resources in tree breeding programs that aim to improve wood quality.}, number={2}, journal={Annals of Forest Science}, publisher={Springer Science and Business Media LLC}, author={Isik, Fikret and Mora, Christian R. and Schimleck, Laurence R.}, year={2011}, month={Feb}, pages={283–293} }
 @article{mora_schimleck_isik_mahon_clark_daniels_2009, title={Relationships between acoustic variables and different measures of stiffness in standing Pinus taeda trees}, volume={39}, ISSN={["0045-5067"]}, DOI={10.1139/X09-062}, abstractNote={ Acoustic tools are increasingly used to estimate standing-tree (dynamic) stiffness; however, such techniques overestimate static stiffness, the standard measurement for determining modulus of elasticity (MOE) of wood. This study aimed to identify correction methods for standing-tree estimates making dynamic and static stiffness comparable. Sixty Pinus taeda L. trees, ranging from 14 to 19 years old, obtained from genetic tests established in the southeastern United States, were analyzed. Standing-tree acoustic velocities were measured using the TreeSonic tool. Acoustic velocities were also recorded in butt logs cut from the same trees using the Director HM200. A strong but biased relationship between tree and log velocities was observed, with tree velocities 32% higher (on average) than the corresponding log velocities. Two correction methods, one for calibrating tree velocities and one for accounting for differences in wood moisture content, were used to determine an adjusted MOE. After correction, adjusted MOE estimates were in good agreement with static longitudinal MOE values measured on clearwood specimens obtained from the trees, and no systematic bias was observed. The results of this study show that acoustic estimates of MOE on standing trees largely depend on how the data are processed and the reference method used. }, number={8}, journal={CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE}, publisher={Canadian Science Publishing}, author={Mora, Christian R. and Schimleck, Laurence R. and Isik, Fikret and Mahon, Jerry M., Jr. and Clark, Alexander, III and Daniels, Richard F.}, year={2009}, month={Aug}, pages={1421–1429} }
 @article{mora_schimleck_isik_2008, title={Near infrared calibration models for the estimation of wood density in Pinus taeda using repeated sample measurements}, volume={16}, ISSN={["0967-0335"]}, DOI={10.1255/jnirs.816}, abstractNote={ Near infrared (NIR) diffuse reflectance was used for the estimation of air-dry density and basic density in wood radial strip samples obtained at breast height (1.4 m) from 60 Pinus taeda trees established in three progeny tests in the south-eastern United States. NIR calibration models were fitted using raw spectra and pre-processed spectra with second derivative, multiplicative scatter correction and orthogonal signal correction. Successful calibrations were obtained for both wood properties using data collected in consecutive 10 mm sections from the samples. Data pre-processing did not result in model improvements compared to the models fitted using raw data. The effects of using repeated measures were evaluated by incorporating serial correlation into the partial least squares regression algorithm. The empirical autocorrelation of the normalised residuals showed that serial dependence among residuals was successfully removed by using an autoregressive correlation structure of second order. However, because the initial dependence among observations was not strong, the predictions were similar using the modified algorithm to those obtained with the traditional approach. These results indicate that the use of repeated measurements does not represent a serious problem for the development of NIR calibration models for the prediction of wood properties using radial samples measured in 10 mm sections and that the specification of the correlation structure may not be required when the models are used only for predictive purposes. }, number={6}, journal={JOURNAL OF NEAR INFRARED SPECTROSCOPY}, publisher={SAGE Publications}, author={Mora, Christian R. and Schimleck, Laurence R. and Isik, Fikret}, year={2008}, pages={517–528} }
 @article{mora_allen_daniels_clark_2007, title={Modeling corewood-outerwood transition in loblolly pine using wood specific gravity}, volume={37}, ISSN={["1208-6037"]}, DOI={10.1139/X06-250}, abstractNote={ A modified logistic function was used for modeling specific-gravity profiles obtained from X-ray densitometry analysis in 675 loblolly pine ( Pinus taeda L.) trees in four regeneration trials. Trees were 21 or 22 years old at the time of the study. The function was used for demarcating corewood, transitional, and outerwood zones. Site and silvicultural effects were incorporated into the model. Heteroscedasticity and within-group correlation were accounted for by specifying the variance and serial-correlation structure, respectively. The estimated transition zone was located between rings 5 and 15, and the outerwood demarcation point varied from rings 12 to 15. No effects of treatments on the demarcation points were observed; however, site preparation and fertilization affected the lower asymptotes of the curves in all sites. A geographical trend for the demarcation point was observed, with the northern site requiring more time to reach a plateau in specific gravity compared with the southern sites. The diameter of the juvenile core was increased as a result of the treatments. However, the amount of corewood was not statistically affected, ranging from 55% in the north to 75% in the south, except at one site where fertilization decreased the percentage of corewood. }, number={6}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, author={Mora, Christian R. and Allen, H. Lee and Daniels, Richard F. and Clark, Alexander}, year={2007}, month={Jun}, pages={999–1011} }
 @article{schimleck_sturzenbecher_mora_jones_daniels_2005, title={Comparison of Pinus taeda L. wood property calibrations based on NIR spectra from the radial-longitudinal and radial-transverse faces of wooden strips}, volume={59}, ISSN={["0018-3830"]}, DOI={10.1515/HF.2005.034}, abstractNote={Abstract}, number={2}, journal={HOLZFORSCHUNG}, author={Schimleck, LR and Sturzenbecher, R and Mora, C and Jones, PD and Daniels, RF}, year={2005}, pages={214–218} }
 @article{schimleck_mora_daniels_2004, title={Estimation of tracheid morphological characteristics of green Pinus taeda L. radial strips by near infrared spectroscopy}, volume={36}, number={4}, journal={Wood and Fiber Science}, author={Schimleck, L. R. and Mora, C. and Daniels, R. F.}, year={2004}, pages={527–535} }
 @article{schimleck_mora_daniels_2003, title={Estimation of the physical wood properties of green Pinus taeda radial samples by near infrared spectroscopy}, volume={33}, ISSN={["0045-5067"]}, DOI={10.1139/X03-173}, abstractNote={ The application of near infrared (NIR) spectroscopy to the green wood of radial samples (simulated increment cores) and the development of calibrations for the prediction of wood properties are described. Twenty Pinus taeda L. (loblolly pine) radial strips were characterized in terms of air-dry density, microfibril angle (MFA), and stiffness. NIR spectra were obtained in 10-mm steps from the radial longitudinal and transverse faces of each sample and used to develop calibrations for each property. NIR spectra were collected when the wood was green (moisture content ranged from approximately 100% to 154%) and dried to approximately 7% moisture content. Relationships between measured and NIR estimates for green wood were good; coefficients of determination (R2) ranged from 0.79 (MFA) to 0.85 (air-dry density). Differences between calibrations developed using the radial longitudinal and transverse faces were small. Calibrations were tested on an independent set. Predictive errors were relatively large for some green samples and relationships were moderate; R2p ranged from 0.67 (MFA) to 0.81 (stiffness). Dry wood calibrations demonstrated strong predictive relationships with R2p ranging from 0.87 (air-dry density) to 0.95 (stiffness). NIR spectroscopy has the potential to predict the air-dry density, MFA, and stiffness of 10-mm sections of green P. taeda wood samples. }, number={12}, journal={CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE}, author={Schimleck, LR and Mora, C and Daniels, RF}, year={2003}, month={Dec}, pages={2297–2305} }