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 non-exhaustive 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 pith-ward cell walls
• Mean thickness of bark-ward 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 / non-solitary cells
• Mean Mork's index (thickness-to-span 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 pith-ward cell walls
• Mean thickness of bark-ward 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 / non-solitary cells
• Mean Mork's index (thickness-to-span 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 pith-ward cell wall
• Thickness of bark-ward 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 (thickness-to-span 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.