Class 1: 0-0.25 m stem length; 1 stem per clump
Class 2: 0.25-0.5 m stem length; 1 stem per clump
Class 3: > 0.5 m stem length; 1 stem per clump
Class 4a: < 0.5 m stem length; 1-3 stem per clump
Class 4b: < 0.15 m stem length; 1-3 stem per clump
Class 4c: 0.15-0.3 m stem length; 1-3 stem per clump
Class 4d: 0.3-0.5 m stem length; 1-3 stem per clump
Class 4e: 0.5-1 m stem length; 1-3 stem per clump
Class 4f: 1-3 m stem length; 1-3 stem per clump
Class 4g: 3-6 m stem length; 1-3 stem per clump
Class 4h: 6-10 m stem length; 1-3 stem per clump
Class 5a: < 0.5 m stem length; 4-6 stems per clump
Class 5b: < 0.15 m stem length; 4-6 stems per clump
Class 5c: 0.15- 0.3 m stem length; 4-6 stems per clump
Class 5d: 0.3-0.5 m stem length; 4-6 stems per clump
Class 5e: 0.5-1 m stem length; 4-6 stems per clump
Class 5f: 1-3 m stem length; 4-6 stems per clump
Class 5g: 3-6 m stem length; 4-6 stems per clump
Class 5h: 6-10 m stem length; 4-6 stems per clump
Class 5i: >10 m stem length; 4-6 stems per clump
Class 6a: < 0.5 m stem length; ≥7 stems per clump
Class 6b: < 0.15 m stem length; ≥7 stems per clump
Class 6c: 0.15-0.3 m stem length; ≥7 stems per clump
Class 6d: 0.3-0.5 m stem length; ≥7 stems per clump
Class 6e: 0.5-1 m stem length; ≥7 stems per clump
Class 6f: 1-3 m stem length; ≥7 stems per clump
Class 6g: 3-6 m stem length; ≥7 stems per clump
Class 6h: 6-10 m stem length; ≥7 stems per clump
Class 6i: >10 m stem length; ≥7 stems per clump

Class 1: 0-0.25 m stem length; 1 stem per clump
Class 2: 0.25-0.5 m stem length; 1 stem per clump
Class 3: > 0.5 m stem length; 1 stem per clump
Class 4a: < 0.5 m stem length; 1-3 stem per clump
Class 4b: < 0.15 m stem length; 1-3 stem per clump
Class 4c: 0.15-0.3 m stem length; 1-3 stem per clump
Class 4d: 0.3-0.5 m stem length; 1-3 stem per clump
Class 4e: 0.5-1 m stem length; 1-3 stem per clump
Class 4f: 1-3 m stem length; 1-3 stem per clump
Class 4g: 3-6 m stem length; 1-3 stem per clump
Class 4h: 6-10 m stem length; 1-3 stem per clump
Class 5a: < 0.5 m stem length; 4-6 stems per clump
Class 5b: < 0.15 m stem length; 4-6 stems per clump
Class 5c: 0.15- 0.3 m stem length; 4-6 stems per clump
Class 5d: 0.3-0.5 m stem length; 4-6 stems per clump
Class 5e: 0.5-1 m stem length; 4-6 stems per clump
Class 5f: 1-3 m stem length; 4-6 stems per clump
Class 5g: 3-6 m stem length; 4-6 stems per clump
Class 5h: 6-10 m stem length; 4-6 stems per clump
Class 5i: >10 m stem length; 4-6 stems per clump
Class 6a: < 0.5 m stem length; ≥7 stems per clump
Class 6b: < 0.15 m stem length; ≥7 stems per clump
Class 6c: 0.15-0.3 m stem length; ≥7 stems per clump
Class 6d: 0.3-0.5 m stem length; ≥7 stems per clump
Class 6e: 0.5-1 m stem length; ≥7 stems per clump
Class 6f: 1-3 m stem length; ≥7 stems per clump
Class 6g: 3-6 m stem length; ≥7 stems per clump
Class 6h: 6-10 m stem length; ≥7 stems per clump
Class 6i: >10 m stem length; ≥7 stems per clump