Conversion of quantitative abiotic variables into classes for contingency analysis.
| Variables | Class 1 | Class 2 | Class 3 | Class 4 | Class 5 |
|---|---|---|---|---|---|
| Total irradiation May to August (hours) | 205–480 | 481–755 | 756–1030 | 1031–1305 | 1306–1615 |
| Street width (m / ft) | 8.9–10.9 | 11.0–14.2 | 14.3–19.8 | ||
| (29.2–35.8) | (36.0–46.6) | (46.9–65.0) | |||
| Distance from tree to curb (m / ft) | 0.45–1.0 | 1.01–2.0 | 2.01–2.3 | ||
| (1.50–3.28) | (3.30–6.56) | (6.59–7.55) | |||
| Tree pit volume (m3 / ft3) | 1.0–2.0 | 2.1–3.0 | 3.1–5.0 | 5.1–9.6 | |
| (35.3–70.6) | (74.2–105.9) | (109.5–176.6) | (180.1–339.0) | ||
| Penetration resistance at soil surface (kPa / PSI) | 0–500 | 501–1000 | 1001–1500 | 1501–2000 | |
| (0.0–72.5) | (72.7–145.0) | (145.2–217.5) | (217.7–290.1) | ||
| Penetration resistance at 15 cm (kPa / PSI) | 0–500 | 501–1000 | 1001–1500 | 1501–2000 | |
| (0.0–72.5) | (72.7–145.0) | (145.2–217.5) | (217.7–290.1) | ||
| Penetration resistance at 30 cm (kPa / PSI) | 0–500 | 501–1000 | 1001–1500 | 1501–2000 | |
| (0.0–72.5) | (72.7–145.0) | (145.2–217.5) | (217.7–290.1) | ||
| Penetration resistance at 45 cm (kPa / PSI) | 0–500 | 501–1000 | 1001–1500 | 1501–2000 | |
| (0.0–72.5) | (72.7–145.0) | (145.2–217.5) | (217.7–290.1) | ||
| Soil K (mg/kg and oz/lb) | 0–150 | 151–250 | 251–350 | 351–450 | 451–650 |
| (0.0–0.00239) | (0.00240–0.00400) | (0.00401–0.00560) | (0.00561–0.00721) | (0.00722–0.01040) | |
| Soil Ca (mg/kg and oz/lb) | 0–3000 | 3001–5000 | 5001–8000 | 8001–11000 | |
| (0.0–0.0480) | (0.0481–0.0801) | (0.0802–0.1282) | (0.1283–0.1764) | ||
| Soil Mg (mg/kg and oz/lb) | 0–175 | 176–300 | 301–475 | 476–745 | |
| (0.0–0.00280) | (0.00281–0.00481) | (0.00482–0.00761) | (0.00762–0.0119) | ||
| Soil Na (mg/kg and oz/lb) | 0–250 | 251–500 | 501–750 | 751–1000 | 1001–1758 |
| (0.0–0.0040) | (0.00401–0.00801) | (0.00802–0.01202) | (0.01203–0.01603) | (0.01604–0.02819) | |
| Soil Zn (mg/kg and oz/lb) | 0–20.0 | 20.1–40.0 | 40.1–60.0 | 60.1–80.0 | 80.1–162 |
| (0.0–0.000320) | (0.000321–0.000641) | (0.000642–0.000962) | (0.000963–0.001282) | (0.001283–0.002597) | |
| Soil Cu (mg/kg and oz/lb) | 0–7.0 | 7.1–14.0 | 14.1–28.0 | 28.1–42.0 | 42.1–130 |
| (0.0–0.000112) | (0.000113–0.000224) | (0.000225–0.000449) | (0.000450–0.000673) | (0.000674–0.00208) | |
| Soil Fe (mg/kg and oz/lb) | 145–210 | 211–280 | 281–350 | 351–615 | |
| (0.00232–0.00337) | (0.00338–0.00449) | (0.00450–0.00561) | (0.00562–0.00986) | ||
| Soil Mn (mg/kg and oz/lb) | 0–15.0 | 15.1–30.0 | 30.1–45.0 | 45.1–106 | |
| (0.0–0.000240) | (0.000241–0.000481) | (0.000482–0.000721) | (0.000722–0.001699) | ||
| Soil P (mg/kg and oz/lb) | 0–80 | 81–160 | 161–240 | 241–320 | 321–730 |
| (0.0–0.00128) | (0.00129–0.00256) | (0.00257–0.00385) | (0.00386–0.00513) | (0.00514–0.01170) | |
| Soil pH | 5.2–6.0 | 6.1–6.5 | 6.6–7.0 | 7.1–7.5 | 7.6–8.3 |
| Soil organic matter content (%) | 0.0–5.0 | 5.1–10.0 | 10.1–15.0 | 15.1–20.0 | 20.1–26.8 |