Figure legends
FIGURE 1: Representative samples of sapwood area staining for six main shrub encroacher species in a semiarid savanna in Namibia. A)Catophractes alexandri , B) Colophospermum mopane , C) Dichrostachys cinerea , D)Senegalia mellifera , E) Vachellia nebrownii ,F) Vachellia reficiens .
FIGURE 2: Delineation of sapwood area based on sapwood staining in C. alexandri. The following areas are outlined by 3 white lines: A) total area, B) wood area, and C) heartwood area.
FIGURE 3. Allometric relationship between stem diameter (Dstem) and sapwood area (SA) and relationship between stem diameter (Dstem) for six main shrub encroacher species in a semiarid savanna in Namibia. Solid black lines are the regression lines calculated by the models, dashed black lines are the 95% confidence intervals, and the grey line is the predicted relationship according to the WBE model (slope = 2.33) (West 1999) with species-specific intercepts.
FIGURE 4. relative sapwood area (relative SA) for six main shrub encroacher species in a semiarid savanna in Namibia. Relative sapwood area is sapwood area divided by the wood area of the cross-section.
FIGURE 5. Relationship between crown area (CA) and total sapwood area (SAtot) for six main shrub encroacher species in a semiarid savanna of Namibia. Solid lines are the regression lines calculated by the models; dashed black lines are the 95% confidence intervals.