Output Parameters
ROXAS produces >120 parameters on the entire image, annual ring and individual cell level and saves them into MS Excel and text files. It
also measures characteristics of conifer needles. Below is a nonexhaustive overview.
Output for the entire image:
 Area of analyzed tissue
 Number of annual rings
 Mean ring area
 Mean ring width
 Overall number of cells
 Mean number of cells per ring
 Accumulated cell lumen area
 Mean cell lumen area
 Mean radial cell lumen diameter
 Mean tangential lumen diameter
 Mean thickness of pithward cell walls
 Mean thickness of barkward cell walls
 Mean thickness of 'left' cell walls (viewed from pith to bark)
 Mean thickness of 'right' cell walls (viewed from pith to bark)
 Mean thickness of tangential cell walls
 Mean thickness of radial cell walls
 Mean cell wall thickness (average of tangential and radial walls)
 Mean hydraulic diameter (Dh)
 Cell density (no./mm2)
 Percentage of conductive area
 Total hydraulic conductivity (Kh) based on Poiseuille’s law
 Specific hydraulic conductivity (Ks) based on Poiseuille’s law
 Vessel grouping index (sensu Carlquist; see Fig. 1 below)
 Vessel solitary fraction
 Mean group size of grouped / nonsolitary cells
 Mean Mork's index (thicknesstospan ratio in radial direction)
 Mean bending resistance index [(t/b)^{2}] (see Fig. 3 below)
 Number of needles
 Mean, minimum and maximum conifer needle surface
 Mean, minimum and maximum conifer needle length (considering curvatures! See Fig. 4 below)
 Mean, minimum and maximum conifer needle width
Output for each ring:
 Calendar year of each ring
 Ring area
 Ring width
 Number of cells
 Accumulated cell lumen area
 Mean cell lumen area
 Mean radial cell lumen diameter
 Mean tangential lumen diameter
 Mean thickness of pithward cell walls
 Mean thickness of barkward cell walls
 Mean thickness of 'left' cell walls (viewed from pith to bark)
 Mean thickness of 'right' cell walls (viewed from pith to bark)
 Mean thickness of tangential cell walls
 Mean thickness of radial cell walls
 Mean cell wall thickness (average of tangential and radial walls)
 Mean hydraulic diameter (Dh)
 Cell density (no./mm2)
 Percentage of conductive area
 Total hydraulic conductivity (Kh) based on Poiseuille’s law
 Specific hydraulic conductivity (Ks) based on Poiseuille’s law
 Vessel grouping index (sensu Carlquist; see Fig. 1 below)
 Vessel solitary fraction
 Mean group size of grouped / nonsolitary cells
 Mean Mork's index (thicknesstospan ratio in radial direction)
 Mean bending resistance index [(t/b)^{2}] (see Fig. 3 below)
Output for each cell or conifer needle:
 Assignment to ring
 Absolute radial position in the ring (distance from ring border)
 Relative position in the ring (from 0 to 100%)
 Number of touching vessels (belonging to the same grouping; see Fig. 1 below)
 Aspect ratio (ratio of minor to major axis)
 Angle of major axis
 Thickness of pithward cell wall
 Thickness of barkward cell wall
 Thickness of 'left' cell wall (viewed from pith to bark)
 Thickness of 'right' cell wall (viewed from pith to bark)
 Thickness of tangential cell walls
 Thickness of radial cell walls
 Mean cell wall thickness (average of tangential and radial walls)
 Hydraulic conductivity (Kh) based on Poiseuille’s law
 Mork's index (thicknesstospan ratio in radial direction)
 Bending resistance index [(t/b)^{2}] (see Fig. 3 below)
 Conifer needle surface
 Conifer needle length (considering curvatures! See Fig. 4 below)
 Conifer needle width

Fig. 1: ROXAS automatically quantifies vessel grouping patterns. In the right panel, vessels belonging to different vessel group sizes as detected by ROXAS are depicted in different colors. Verbascum thapsus. Scale bar: 200 μm. Adjusted from von Arx et al. 2013, IAWA J




Fig. 2:
Illustration of the Mork's index. In conifers, a value of 1 within a ring is often assumed to mark the transition from the earlywood to the latewood.




Fig. 3:
Illustration of the 'bending resistance' index [(t/b)^{2}]. This parameter is a proxy for the implosion safety of cells when water potential in the xylem gets very low.




Fig. 4:
Example of conifer needle measurements. Pinus sylvestris needles scanned at 300 dpi with a flatbed scanner using the 'transparency' setting to avoid shadows.
