Article Figures & Data
Figures
- Figure 1
Original photographic image of mulberry captured by the CI-100.
- Figure 2
Profile view of mulberry (same tree as in Figure 1) before the original 35-mm photograph was video scanned into the AgVision System.
- Figure 3
Comparison of estimated leaf area indices with actual leaf area index for 5 methods including a) AccuPAR Ceptometer after removal of measurements resulting in gap fractions ≥1.0; b) CI-100 processed at 130-degree view and 62 threshold; c) 35-mm photograph image processed with AgVision System; d) LAI-2000 processed with ellipsoidal inversion; e) logarithmic regression equation. The 3 points for each tree represent replications at full crown, –10, and –20 quadrat leaf sample levels. Replication estimates after crown reduction were commonly higher than before reduction. The logarithmic regression equation was applied to mulberries only, with no replications.
- Figure 4
Percentage of measurements taken in each cardinal direction for two instruments, a) AccuPAR, b) CI-100, that produced more accurate LAI estimates. Fourteen sets of measurements were made in the morning and 10 sets in the afternoon (n = 14 in morning and n = 10 in afternoon).
Tables
- Table 1.
The range of measurements, from highest to lowest, taken for each tree for actual leaf area index and estimates. Three measurements were taken for each tree at three levels of crown foliation, but decreases in actual leaf area with removal of each 10-quadrat sample of leaves were not reflected by the estimation methods; estimates made at reduced crown levels were often higher than full-crown estimates. Only the actual measurements decreased with leaf removal.
Tree Actual AccuPAR CI-100 Image LAI-2000 Logarithm Mulberry 01 3.15–3.12 2.16–1.48 2.92–2.65 3.06–2.72 4.25–2.86 3.32 Mulberry 02 2.26–2.25 1.12–0.37 3.38–3.31 2.65–2.14 4.16–1.65 3.73 Mulberry 03 3.89–3.86 1.30–0.92 3.65–2.70 2.80–2.29 3.51–2.05 3.13 Mulberry 04 3.58–3.57 1.61–0.42 4.07–2.66 3.55–3.21 2.98–2.52 4.08 Mulberry 05 3.24–3.22 1.59–1.35 3.91–3.43 2.72–2.53 2.84–2.46 3.18 Mulberry 06 2.35–2.34 <0.00 n/a 3.35–3.00 3.23–0.83 2.86 Cherry 01 6.29–6.26 1.92–0.99 3.30–2.37 6.05–5.89 7.57–4.17 n/a Cherry 02 4.89–4.86 2.48–0.49 4.12–3.29 7.24–6.35 4.61–2.73 n/a - Table 2.
Paired t-test results for original leaf area index data (no processing) and data processed using the methods listed. Analyses of variance were conducted prior to t-tests for all methods to estimate the standard errors, with the exception of logarithmic regression. Methods produced LAI estimates significantly different from actual LAI at 0.05-level if t > t-critical.
Method Processing Mean Estim. LAI Sample Mean Difference 
SE n df t P-value t critical α = 0.05 (2-tail) Actual 100% destructive harvest 3.694 n/a 0.261* 24 7 — — — 3.887 n/a 0.273 21 6 — — — 3.076 n/a 0.266 6 5 — — — AccuPAR None 0.947 2.747 0.403 24 7 6.28 <0.01 2.365† ≥1 transmissions removed 1.107 2.587 0.419 24 7 6.177 <0.01 2.36† CI-100 None 0.354 3.533 0.535 21 6 6.599 <0.01 2.447† 130° w/ 62 threshold 3.304 0.583 0.547 21 6 1.065 0.33 2.447 130° w/ mixed thresholds 2.871 1.016 0.486 21 6 2.089 0.08 2.447 150° w/ 62 threshold 3.102 0.785 0.541 21 6 1.45 0.2 2.447 150° w/ mixed thresholds 2.949 0.938 0.467 21 6 2.009 0.09 2.447 Image processing None 3.7 –0.006 0.345 24 7 0.017 0.99 2.365 LAI-2000 None 1.107 2.588 0.452 24 7 5.722 <0.01 2.365† Lang method 3.099 0.467 0.235 24 7 1.988 0.09 2.365 Ellipsoidal inversion 3.287 0.407 0.26 24 7 1.565 0.16 2.365 Logarithmic regression None 3.383 –0.307 0.181 6 5 –1.017 0.36 2.015
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