Article Figures & Data
Figures
- Figure 1.
Circling barriers are used to protect hardscape elements from damage by deflecting tree roots vertically to the bottom of the barrier. In this study, four commercially available root barriers were used to examine root development inside and outside barriers.
- Figure 2.
Full root systems were excavated inplace using a hydroexcavation technique. Soil is washed from the roots and the soil-water slurry vacuumed into a large holding tank.
- Figure 3.
Control trees (no barriers) developed shallow, lateral root systems with most roots found in the surface 15 cm (6 in.) of soil.
- Figure 4.
Roots of trees with circling root barriers tended to grow towards the soil surface after growing under the barrier. Barrier wall was 30 cm (12 in.) from trunk and 38 cm (15 in.) deep. Arrows identify location of barrier wall.
Tables
Barrier Material Thickness Special features Biobarrier Spun polypropylene 3 oz. Fabric with trifluralin. Typar fabric Spun polypropylene 3 oz. Fabric without trifluralin. Deep root Polypropylene 80 mil Plastic with ribs on inside walls to direct roots vertically. Root Block Polyethylene 80 mil Plastic without ribs on inside walls. - Table 2.
Circling barrier effects on mean root number (>2mm diameter) for ash and poplar at 30,90, and 150 cm outside the barrier and at equivalent distances for controls.
Treatment Poplar Ash Distance from barrier (cm) Distance from barrier (cm) 30 90 150 30 90 150 Root number Root number Biobarrier 13.3 b 13.3 b 8.4 b 10.1 ab 8.3 ab 3.0 Deep Root 10.6 b 9.2 b 6.7 b 5.6 c 4.1 c 1.7 Root Block 12.0 b 9.6 b 6.2 b 5.8 c 4.5 be 1.4 Typar 11.4b 11.4 b 6.6 b 6.4 be 4.9 be 1.4 Control 19.4 a 20.5 a 13.9 a 11.1 a 9.7 a 3.1 n.s. Means within columns followed by same letter are not significantly different using Fisher’s Protected LSD (p =0.05). n.s. = no significant difference. Each mean is calculated across main plot treatments (10 trees). No significant interactions for main x subplots were found.
- Table 3.
Subsurface barrier effects on mean root depth (cm) at 30,90, and 150 cm outside barriers.
Treatment Poplar Ash Distance from barrier (cm) Distance from barrier (cm) 30 90 150 30 90 150 Root depth (cm) Root depth (cm) With subsurface barrier 28.3 a 17.9 a 12.1 24.3 a 16.4 a 11.7a Without subsurface barrier 20.3 b 10.8 b 9.5 16.1b 8.3 b 6.0 b n.s. Means within columns followed by the same letter are not significantly different using Fisher’s Protected LSD (p=0.05). n.s = not significantly different. Means calculated across subtreatments and block (25 trees). There were no significant main x subplot interactions.
- Table 4.
Mean bulk density (g/cc) of soil samples taken at 7.6 and 61 cm distances from outside of bariers and at 7.6 and 38 cm depths in plots with and without cultivation (subsurface barriers). Al bulk densities were corrected for gravel content (30% by volume).
Distance (cm) Depth (cm) Cultivation (with subsurface barrier) No Cultivation (without subsurface barrier) bulk density (g/cc) bulk density (g/cc) 7.6 7.6 1.49 (.19) 1.51 (.10) 61.0 7.6 1.46 (.20) 1.49 (.03) 7.6 38.0 1.60 (.05) 1.64 (.03) 61.0 38.0 1.58 (.05) 1.72 (.10) Standard deviation of samples (n=3) in parentheses after each mean.
Standard error of means = 0.086.
- Table 5.
Cultivation effects (subsurface barrier treatments) on mean root number in 0-15 cm depth at 30,90, and 150 cm from outside of barriers for circling barrier treatments and controls combined.
Poplar Ash 30 90 150 30 90 150 Cultivation (with subsurface barrier) 2.0 a 4.6 a 4.3 a 1.8 a 3.3 a 1.6 No cultivation (without subsurface barrier) 5.4 b 11.3b 8.2 b 5.3 b 5.5 b 1.3 n.s. Means within columns followed by the same letter are not significantly different using Fisher’s Protected LSD (p=0.05). n.s. = not significantly different. Means calculated from all treatments and replicates combined over each main plot (25 trees) and there were no significant interactions.
In this issue
Jump to section
Related Articles
Cited By...
- No citing articles found.