Branch Junction Characteristics Affect Hydraulic Segmentation in Red Maple

The effect of branch morphological characteristics on hydraulic segmentation in red maple branch junctions was determined using hydraulic conductivity measurements. Relative branch size impacted hydraulic conductivity at the branch junction. Conductivity ratios were directly proportional to the ratio of branch diameter to stem diameter. Junctions with perpendicular branches showed lower hydraulic conductivities than more upright branches. The presence of visible branch collars was a good indicator of low branch junction conductivity. Branches having pith that was continuous with trunk pith were associated with codominant stems that had high branch junction conductivity. Branch junction hydraulic conductivity was positively correlated with the amount of discolored wood development after branch removal. This finding may indicate that similar anatomical properties are responsible for both branch junction decay resistance and hydraulic segmentation.