Patterns in Foliar Isotopic Nitrogen, Percent Nitrogen, and Site Index for Managed Forest Systems in the United States
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Sites
2.2. Field Data Collection
2.3. Laboratory Analysis for Foliar %N and δ15N
2.4. Foliar Spectral Reflectance Data
2.5. Statistical Analysis
3. Results
3.1. Foliar δ15N and %N
3.2. Reflectance and Foliar δ15N
3.3. Reflectance, Site Index and δ15N
4. Discussion
4.1. Prediction of Foliar δ15N from Spectral Reflectance
4.2. δ15. N, Reflectance and Site Index
4.3. Moving toward Assessment across Spatial and Temporal Scales
5. Summary and Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Index or λ | Equation (nm) | Reference |
---|---|---|
ACI | Rgreen/RNIR | [44] |
ARI | (1/R550) − (1/R700) | [45] |
CARI | [(R700 − R670) − 0.2 ∗ (R700 − R550)] | [46] |
CIred edge | RNIR/Rred edge − 1 | [47] |
CRI 1 | (1/R510) − (1/R550) | [48] |
CRI 2 | (1/R510) − (1/R700) | [48] |
DCI | FDR705/FDR722 | [49] |
DmaxRE | FDRmax(680–750) | [50] |
DmaxRE/D703 | FDRmax(680–750)/D(703) | [50] |
EVI | 2.5 ∗ (RNIR − Rred)/(RNIR + 6 ∗ Rred − 7.5 ∗ Rblue + 1) | [51] |
Gökkaya 590 | R590 | [52] |
Gökkaya 1023 | R1023 | [52] |
Gökkaya 1507 | R1507 | [52] |
Gökkaya 2173 | R2173 | [52] |
G&M 2 | R750/R700 | [53] |
HNDVI | (R827 − R668)/R827 + R668) | [54] |
Lic 1 | (R800 − R680)/(R800 + R680) | [55] |
Lignin 1730 | R1730 | [32] |
Lignin 2300 | R2300 | [32] |
mARI | [(1/R550) − (1/R700)] ∗ R800 | [47] |
MCARI | [(R700 − R670) − 0.2 ∗ (R700 − R550)] ∗ (R700/R670) | [56] |
MNDVI | (R750 − R705)/(R750 + R705) | [17] |
NDNI | (L1510 − L1680)/(L1510 + L1680) | [42] |
NDVI | (RNIR − Rred)/(RNIR + Rred) | [57] |
Nitrogen 2100 | R2100 | [32] |
PRI | (R531 − R570)/(R531 + R570) | [58] |
PSND | (R800 − R650)/(R800 + R650); (R800 − R675)/(R800 + R675) | [59] |
PSRI | (R680 − R500)/R750 | [60] |
PSSR | (R800/R650); (R800/R675) | [59] |
REIP | λ of FDRmax(650–750) | [12] |
RGRI | Rred/Rgreen | [61] |
SIPI | (R800 − R445)/(R800 − R680) | [62] |
SR | RNIR/Rred | [63] |
VIgreen | (Rgreen − Rred)/(Rgreen + Rred) | [64] |
Vog 1 | R740/R720 | [14] |
Vog 2 | (R734 − R747)/(R715 + R726) | [14] |
Wang 619 | R619 | [30] |
Wang 695 | R695 | [30] |
Wang 1135 | R1135 | [30] |
Wang 603 | FDL603 | [30] |
Wang 639 | FDL639 | [30] |
Wang 702 | FDL702 | [30] |
Wang 704 | FDL704 | [30] |
Douglas-Fir | Loblolly Pine | |||
---|---|---|---|---|
δ15N | %N | δ15N | %N | |
Minimum | −3.2 | 1.2 | −7.5 | 0.8 |
Maximum | −0.9 | 1.5 | −1.2 | 1.4 |
Mean | −2.1 | 1.4 | −4.2 | 1.1 |
Range | 2.3 | 0.3 | 6.3 | 0.6 |
Dataset | p-Value | Coefficient | R2 | Adj. R2 | RMSE (‰) | Press RMSE (‰) |
---|---|---|---|---|---|---|
Douglas-fir (n = 10) | 0.30 | 2.29 | 0.13 | 0.02 | 0.68 | 0.74 |
Loblolly pine (n = 18) | 0.04 * | 4.18 | 0.25 | 0.20 | 1.34 | 1.50 |
Combined (n = 28) | <0.01 * | 5.37 | 0.47 | 0.45 | 1.21 | 1.25 |
Dataset | λ (nm) or Index | Coefficient | R2 | Adj. R2 | RMSE (‰) | Press RMSE (‰) | Shapiro–Wilk | |
---|---|---|---|---|---|---|---|---|
W | p-Value | |||||||
Douglas-fir (n = 10) | SDR 543 | 85,219.43 | 0.65 | 0.61 | 0.43 | 0.57 | 0.96 | 0.77 |
SDR 543, ARI | 109,936.02, −1.10 | 0.81 | 0.75 | 0.35 | 0.53 | 0.91 | 0.29 | |
Loblolly pine (n = 18) | FDR 587, L748 | 10,909.27, −28.37 | 0.54 | 0.54 | 1.11 | 1.19 | 0.94 | 0.26 |
FDR 587, PSSR, Wang 619 | 18,171.06, 1.71, 166.64 | 0.68 | 0.61 | 0.96 | 1.07 | 0.97 | 0.78 | |
Combined (n = 28) | FDL 1167, SDR 570 | 9118.40, 54,698.60 | 0.63 | 0.61 | 1.03 | 1.07 | 0.95 | 0.21 |
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Buntrock, L.; Thomas, V.A.; Strahm, B.D.; Fox, T.; Harrison, R.; Himes, A.; Littke, K. Patterns in Foliar Isotopic Nitrogen, Percent Nitrogen, and Site Index for Managed Forest Systems in the United States. Forests 2022, 13, 1694. https://doi.org/10.3390/f13101694
Buntrock L, Thomas VA, Strahm BD, Fox T, Harrison R, Himes A, Littke K. Patterns in Foliar Isotopic Nitrogen, Percent Nitrogen, and Site Index for Managed Forest Systems in the United States. Forests. 2022; 13(10):1694. https://doi.org/10.3390/f13101694
Chicago/Turabian StyleBuntrock, Laura, Valerie A. Thomas, Brian D. Strahm, Tom Fox, Robert Harrison, Austin Himes, and Kim Littke. 2022. "Patterns in Foliar Isotopic Nitrogen, Percent Nitrogen, and Site Index for Managed Forest Systems in the United States" Forests 13, no. 10: 1694. https://doi.org/10.3390/f13101694
APA StyleBuntrock, L., Thomas, V. A., Strahm, B. D., Fox, T., Harrison, R., Himes, A., & Littke, K. (2022). Patterns in Foliar Isotopic Nitrogen, Percent Nitrogen, and Site Index for Managed Forest Systems in the United States. Forests, 13(10), 1694. https://doi.org/10.3390/f13101694