Table 1.
Statistiacl effects of trampling, defoliation and severing clonal connections on the growth, morphological and mechanical properties of large ramets of Populus simonii
| Trampling (T) | Defoliation (D) | Severing (S) | T × S | D × S | D × T | D × T × S | |
|---|---|---|---|---|---|---|---|
| Growth and morphological properties | |||||||
| Main stem length | 0·00n.s. | 1·17n.s. | 0·23n.s. | 5·77* | 0·09n.s. | 0·07n.s. | 0·34n.s. |
| Vertical height | 21·00*** | 0·02n.s. | 0·04n.s. | 6·02* | 1·86n.s. | 1·56n.s. | 3·09n.s. |
| Basal diameter | 0·22n.s. | 8·66** | 7·01* | 7·82** | 0·05n.s. | 0·78n.s. | 0·38n.s. |
| Leaf mass | 4·49** | 5·49** | 32·75*** | 0·72n.s. | 2·07n.s. | 1·32n.s. | 0·99n.s. |
| Stem mass | 1·88n.s. | 5·08* | 10·82** | 4·19* | 0·16n.s. | 0·16n.s. | 1·33n.s. |
| Fibrous root mass | 0·33n.s. | 0·07n.s. | 5·02* | 6·09* | 0·09n.s. | 1·92n.s. | 0·00n.s. |
| Leaf area ratio | 0·01n.s. | 22·69*** | 2·94n.s. | 0·54n.s. | 0·01n.s. | 0·05n.s. | 0·14n.s. |
| Mechanical properties | |||||||
| Young's modulus | 0·84n.s. | 0·88n.s. | 4·44* | 4·30* | 0·22n.s. | 0·01n.s. | 0·08n.s. |
| Second moment of area | 0·22n.s. | 8·66** | 7·01* | 7·82* | 0·05n.s. | 0·78n.s. | 0·38n.s. |
| Flexural stiffness | 0·98n.s. | 9·55** | 12·51** | 12·53** | 0·00n.s. | 0·58n.s. | 0·54n.s. |
| Break stress | 0·15n.s. | 0·01n.s. | 1·67n.s. | 5·06* | 0·16n.s. | 0·01n.s. | 1·68n.s. |
| Break force (Fbreak) | 1·25n.s. | 4·19* | 12·48** | 12·95** | 0·02n.s. | 0·76n.s. | 2·51n.s. |
| Bend force (Fbend) | 7·17* | 7·42* | 16·51*** | 10·38** | 0·02n.s. | 1·05n.s. | 0·27n.s. |
| Fbreak/Fbend | 9·06** | 3·20n.s. | 3·79n.s. | 0·00n.s. | 0·11n.s. | 0·27n.s. | 2·03n.s. |
F values and significance levels (***P < 0·001, **P < 0·01, *P < 0·05, n.s.P ≥ 0·05) are given; degrees of freedom of dry biomass of fibrous roots are (1,34); degrees of freedom of the others for all the effects are (1,40). Data were ln-transformed before analyses.