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Table III

Analyses of variance of Visual and Digital Crown Transparency mean values per poplar stand (N = 32) calculated with 265 trees data to test the effect of site quality, stand age and understorey management.

N = 32 Crown Transparency

Visual Digital
Source d .f . F Pr > F F Pr > F
Quality 1 75.1 < 0.01 25.7 < 0.01
Management 1 7.2 0.01 0.3 0.61
Age 1 43.4 < 0.01 7.4 0.01
Quality × Management 1 16.5 < 0.01 4.9 0.04
Quality × Age 1 33.9 < 0.01 11.9 < 0.01
Management × Age 1 < 0.1 0.87 0.9 0.3
Quality × Management × Age 1 3.6 0.07 1.3 0.3