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Table III
Comparison of the ability of 11 published models, linking total chlorophyll content (units are given for each model; Y) to Spad units (X), to predict our 13 neotropical trees data set. Relative performance of models was assessed using Root Mean Square Error of Prediction (RMSEP).
| Species | Reference | Model | Unit | RMSEP |
|---|---|---|---|---|
| Betula papyrifera Marsh. | Richardson et al. (2002) | Y = 5,52E – 04 + 4.04E – 04 * X + 1.25E – 05 * X2 | mg cm−2 | 14.67 |
| Betula pendula Roth | Uddling et al. (2007) | Y = 0.0641 * exp(0.0467X) | g m−2 | 35.93 |
| Eucalyptus globules Labill. | Pinkard et al. (2006) | Y = exp(–8.79 + 2.08 * ln(X)) | μg mm−2 | 15.38 |
| Eucalyptus nitens (H. Deane & Maiden) Maiden | Pinkard et al. (2006) | Y = exp(–8.55 + 0.97 * ln(X)) | μg mm−2 | 17.74 |
| Mangifera indica L. | Schaper and Chacko (1991) | Y = –5.4 + 11.1 * X | mg m−2 | 17.08 |
| Malus domestica Borkh | Campbell et al. (1990) | Y = –83 + 2.37 * X | μg cm−2 | 47.86 |
| Oriza sativa L. | Monje and Bugbee (1992) | Y = 1.034 + 0.308 * X + 0.11 * X2 | mg m−2 | 30.31 |
| Solanum tuberosum L. | Uddling et al. (2007) | Y = 0.0913 * exp(0.0415 * X) | g m−2 | 33.60 |
| Triticum aestivum L. | Uddling et al. (2007) | Y = 0.0599 * exp(0.0493 * X) | g m−2 | 46.18 |
| Vigna unguiculata (L.) Walp. | Murillo-Amador et al. (2004) | Y = –2.79 + 0.88 * X | μg cm−2 | 24.98 |
| 6 neotropical trees | Marenco et al. (2009) | Y = 0.53 * exp(0.0364 * X) | mg m−2 | 24.21 |
| 13 neotropical trees | Present study | Y = 117.1 * X/(148.84 – X) | μg cm−2 | 11.59 |