Article Figures & Data
Figures
- Figure 1.
Effect of mulch over root ball on cumulative elm trunk diameter increase (measured in October of indicated year) in the first five years after landscape planting (P < 0.04); vertical bars indicate SE. Note: All trees in both treatments received mulch from the edge of the root ball outward starting at planting Feb 2008; mulch did not impact maples (P > 0.33).
- Figure 2.
Trunk bending stress three years (A) and five years (B) after landscape planting for elms planted even and deep in nursery containers; vertical bars indicate SE. No interactions were significant (P > 0.05); vertical bars indicate SE. Shallow = topmost root 13 mm deep into 11.4 L (#3) and even with substrate surface into 57 L (#15) and 170 L (#45) container; deep = topmost root 64 mm deep into 11.4 L and 57 L containers (128 mm deep total), and even into 170 L container.
- Figure 3.
Bending stress required to winch trunks to increasing angles three (2011) to five (2013) years after landscape planting averaged across mulch, planting depth, and root remediation; n = 40 for each taxa.
For elm (A):
Stress to 1 degree = 12.8 (year) – 1.5 (year2) – 17.3; P < 0.0001, R2 = 0.18.
Stress to 3 degrees = 31.3 (year) – 3.7 (year2) – 44.3; P < 0.0001, R2 = 0.25.
Stress to 5 degrees = 41.4 (year) – 4.9 (year2) – 58.7; P < 0.0001, R2 = 0.27.
For maple (B):
Stress to 1 degree = 4.7 (year) – 0.7 (year2) + 0.06; P < 0.0001, R2 = 0.22.
Stress to 3 degrees = 11.4 (year) – 1.6 (year2) – 4.7; P < 0.0001, R2 = 0.24.
Stress to 5 degrees = 20.0 (year) – 2.8 (year2) – 16.7; P < 0.0001, R2 = 0.27.
Tables
- Table 1.
Effect of nursery planting depth on time required for root remediation at planting (air excavate top of root ball plus prune to remove roots growing over the root collar).
Nursery planting depthz Air excavation time (seconds) Elm Root pruning time (seconds) Total (excavation + prune) time (seconds) Shallow 70 by 185 b 255 b Deep 102 a 328 a 430 a Nursery planting depth Air excavation time (seconds) Maple Root pruning time (seconds) Total (excavation + prune) time (seconds) Shallow 98 bz 380 b 478 b Deep 153 a 756 a 909 a ↵z Shallow = topmost root 13 mm deep into 11.4 L (#3) and even with substrate surface into 57 L (#15) and 170 L (#45) container; deep = topmost root 64 mm deep into 11.4 and 57 L containers (128 mm deep total), and even into 170 L container.
↵y Means followed by a different letter within columns are statistically different at P < 0.05; n = 10.
- Table 2.
Effect of nursery planting depth and root remediation on root attributes five years later after planting into the landscape.
Elm Nursery planting depthz Root remediation at planting % trunk circled at plantingxy % trunk circled 5 years after plantingx Root depth–north (cm) Depth of straightw
roots–north (cm)Depth of descendingv
roots–north (cm)Shallow Yes 36 bu 3 b 14 b 10 b 17 b No 36 b 22 b 26 a 22 a 30 a Deep Yes 68 a 1 b 20 ab 21 a 22 ab No 68 a 55 a 20 ab 20 a 22 ab Maple Nursery planting depthz Root remediation at planting % trunk circled at plantingxy % trunk circled 5 years after plantingx CSA largest circling root–northt (cm2) Depth of straightw roots (cm) Shallow Yes 41 bs 9 c 5 b 13 b No 41 b 66 b 11 ab 16 b Deep Yes 77 a 22 c 15 a 14 b No 77 a 85 a 8 ab 22 a ↵z Shallow = topmost root 13 mm deep into 11.4 L (#3) and even with substrate surface into 57 L (#15) and 170 L (#45) container; deep = topmost root 64 mm deep into 11.4 and 57 L containers (128 mm deep total), and even into 170 L container.
↵y Data presented in Gilman et al. 2010b; means for root pruning yes and no are identical because roots were not pruned in that study.
↵x Percentage of trunk circumference circled with roots > 5 mm diameter.
↵w Straight = root segment just beyond the root ball was oriented < 60 degrees in either compass direction compared to azimuth of parent root inside root ball; depth measured 10 cm outside root ball.
↵v Descending = growing down < 45 degrees in relation to landscape soil surface on north side of tree.
↵u Means for elm followed by a different letter within columns are statistically different at P = 0.05, 0.01, 0.006, 0.003, and 0.02, left to right; n = 10, averaged over mulch treatment due to insignificant interaction (P > 0.05).
↵t Diameter of largest root circling the north half of the tree at the position of the 170 L root ball; there was no effect on circling roots on south side.
↵s Means for maple followed by a different letter within columns are statistically different at P = 0.01, 0.001, 0.008, and 0.04, left to right; n = 10, averaged over mulch treatment because of insignificant interaction (P > 0.05).
- Table 3.
Effect of root remediation when landscape planting and mulch application over the root ball on maple root attributes five years later.
Root remediation at planting Mulch 7 cm deep over root ball % trunk circled 5 years after plantingz Total straighty root CSA (cm2) Depth of straighty roots (cm) Yes Yes 25 bx 45 a 13 b No 7 c 59 a 14 b No Yes 69 a 45 a 22 a No 83 a 22 b 15 b ↵z Percentage of trunk circumference circled with roots > 5 mm diameter.
↵y Straight = root segment just beyond the root ball oriented < 60 degrees in either compass direction compared to azimuth of parent root inside root ball; depth measured 10 cm outside root ball.
↵x Means followed by a different letter within columns are statistically different at P = 0.002, 0.006, and 0.01 left to right, respectively; n = 10, averaged over nursery planting depth due to insignificant interaction with nursery planting depth (P > 0.18).
- Table 4.
Effect of root remediation at planting, mulch, and nursery planting depth on maplez trunk bark death evaluated 15 months after planting, and root depth five years after planting into landscape soil.
Mulch 7 cm deep over root ball Root remediation at planting % circumference of trunk with bark dead Depth of straightyroots (cm) Yes Yes 52 ax 13 b No 19 c 22 a No Yes 41b 14 b No 38 b 15 b Nursery planting depthw Root remediation at planting % circumference of trunk with bark dead Shallow Yes 46 ax No 45 a Deep Yes 41 a No 18 b ↵z Elms experienced no trunk bark death.
↵y Straight = root segment just beyond the root ball oriented < 60 degrees in either compass direction compared to azimuth of parent root inside root ball; depth measured 10 cm outside root ball.
↵x Means followed by a different letter within columns are statistically different at P < 0.001; n = 10, insignificant three-way interaction (P > 0.87).
↵w Shallow = topmost root 13 mm deep into 11.4 L (#3) and even with substrate surface into 57 L (#15) and 170 L (#45) container; deep = topmost root 64 mm deep into 11.4 and 57 L containers (128 mm deep total), and even into 170 L container.
- Table 5.
Effect of mulch application over the root ball on bending stress to tilt elm and maple trunks five yearsz after planting in the landscape.
Elm Mulch 7 cm deep over root ball Bending stress to 5 degrees trunk tilt 5 years after planting (MN/m2) Bending stress to 10 degrees trunk tilt 5 years after planting (MN/m2) Bending stress to 15 degrees trunk tilt 5 years after planting (MN/m2) Yes 25.9 ay 31.6 a 33.4 a No 23.3 b 27.9 b 29.5 b Maple Mulch 7 cm deep over root ball Bending stress to 5 degrees trunk tilt 5 years after planting (MN/m2) Yes 15.5 a No 13.4 b ↵z Bending stress not affected (P > 0.05) years 3 and 4.
↵y Means followed by a different letter within columns are statistically different at P < 0.03; n = 20, averaged over nursery planting depth and root pruning due to insignificant interactions of these two factors with mulch (P > 0.07, elm; and P > 0.22, maple).
- Table 6.
Effect of nursery planting depth and root remediation at planting on bending stress required to winch maple to various trunk tiltsz four yearsy after planting in the landscape.
Nursery planting depthx Root remediation at planting Bending stress to two degrees trunk tilt (MN/m2) Bending stress to 5 degrees trunk tilt (MN/m2) Shallow Yes 12.4 aw 20.1 ab No 11.6 ab 19.0 ab Deep Yes 10.3 b 17.7 b No 12.2 ab 20.8 a ↵z Depth × remediation interaction was insignificant (P = 0.11) for tilting to one degree; mean separation for three and four degrees tilt was identical to five degrees.
↵y There was no impact three and five years after planting.
↵x Shallow = topmost root 13 mm deep into 11.4 L (#3) and even with substrate surface into 57 L (#15) and 170 L (#45) container; deep = topmost root 64 mm deep into 11.4 and 57 L containers (128 mm deep total), and even into 170 L container.
↵w Means followed by a different letter within columns are statistically different at P < 0.05, n = 10, averaged over mulch treatment because three-way interaction with mulch was not significant (P > 0.07).
- Table 7.
Pearson Correlation Coefficients of root attributes (measured 10 cm beyond planted 170 L container root ball) with rest angle and bending stress to tilt trunk 5 and 20 degrees five years after planting.
Elm Root Attribute Trunk rest anglez Trunk bending stress 5 degrees Trunk bending stress 20 degrees CSA leewardy −0.49 0.50 0.54 Straightx CSA leewardy −0.37 0.48 0.51 Ascendingw CSA leewardy −0.48 0.40 0.57 Straight-rootx descendingu CSA NSs 0.39 0.41 Straight-rootx CSA −0.40 0.33 0.40 CSA −0.45 0.33 0.41 Ascendingw CSA −0.61 NS 0.45 Maple Depth straightx roots windwardv NS 0.49 NS Downwardt CSA windwardv 0.40 0.47 NS Depth straight-rootsx NS 0.43 NS Descendingu CSA windwardv 0.40 0.42 NS Straight-rootx CSA windwardv NS 0.41 NS CSA windwardv 0.38 0.37 NS Depth NS 0.37 NS Straight-rootx CSA NS 0.36 NS CSA NS 0.34 NS ↵z Rest angle = trunk angle after releasing pulling cable following winching to 20 degrees trunk tilt.
↵y Growing in the quadrant toward the pulling winch.
↵x Straight = root segment just beyond the root ball oriented < 60 degrees in either compass direction compared to azimuth of parent root inside root ball.
↵w Ascending = growing up toward landscape soil surface.
↵v Windward = growing in the quadrant opposite the pulling winch.
↵u Descending = growing down < 45 degrees in relation to landscape soil surface.
↵t Downward = growing down > 45 degrees in relation to landscape soil surface.
↵s P > 0.05.
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