Effects of Tree Stabilization Systems on Tree Health and Implications for Planting Specifications

Kendra J. Labrosse; Robert C. Corry; Youbin Zheng

doi:10.48044/jauf.2011.029

Article Figures & Data

Figures

Tables

Download figure
Open in new tab
Download powerpoint
Figure 1.
Common tree stabilization systems: a) staking, b) guying, and c) root ball anchoring. Drawing courtesy of K. Labrosse.
Download figure
Open in new tab
Download powerpoint
Figure 2.
TSS observed during field investigations. a) Metal stakes with a hose-covered wires. b) Wooden stakes with a hose-covered wire. c-d) Guy wires covered with a hose and secured to the ground with small metal stakes. Photographs courtesy of K. Labrosse.

Tables

Figures

View popup

Table 1.

Evaluation guide for rating tree health symptoms in the field using visual cues.

Symptoms	Tree condition score
Overall health	1- dead	2- declining	3- injured	4- struggling	5- healthy
Crown dieback	1- entire crown	2- majority	3- half	4- some	5- healthy crown
Girdled trunk	1- entire trunk	2- majority	3- half	4- part	5- no girdling
Pests or diseases	1- infestation	2- evidence across tree	3- isolated	4- some evidence	5- no pests/diseases
Swelling	1- entire trunk	2- major swelling	3- minor	4- beginning	5- no swelling
Leaf scorch	1- entire canopy	2- majority	3- some	4- occasional	5- no scorching
Wilting	1- entire canopy	2- major	3- some	4- a few leaves	5- no wilting
Stunted growth	1- not growing	2- decline	3- some evidence	4- beginning	5- normal growth
Flagging	1- entire canopy	2- many brown leaves	3- some brown leaves drop	4- occasional brown leaf	5- normal leaf
Sprouting/suckering	1- greater than ten suckers	2- five to nine suckers	3- two to four suckers	4- one sucker	5- no suckering

View popup
Table 2.
Land ownership and land use of planting locations for 488 trees observed in Guelph, ON.
Land ownership and use No. trees sampled
Public SWMF^{^z} 156
Park 82
Open space 9
Private Institutional 100
Residential 53
Industrial 64
Commercial 24
↵^zStormwater management facility.

View popup

Table 3.

Genera of 488 trees observed in Guelph, ON, categorized by xylem class, land ownership, and TSS presence.

Species	Public land	Private land	TSS	No TSS
Diffuse-porous
Acer (n = 140)	69	71	62	78
Betula (n = 22)	22	0	16	6
Carpinus (n = 9)	9	0	9	0
Cercidiphyllum (n = 3)	2	1	3	0
Malus (n = 1)	0	1	1	0
Platanus (n = 7)	6	1	1	6
Pyrus (n = 11)	0	11	0	11
Syringa (n = 27)	0	27	15	12
Ring-porous
Celtis (n = 18)	5	13	7	11
Fraxinus (n = 43)	11	32	33	10
Gleditsia (n = 13)	0	13	7	6
Larix (n = 4)	4	0	3	1
Prunus (n = 19)	7	12	9	10
Quercus (n = 39)	30	9	32	7
Tsuga (n = 1)	1	0	1	0
Coniferous/other
Abies (n = 13)	13	0	13	0
Amelanchier (n = 29)	22	7	16	13
Ginkgo (n = 19)	6	13	12	7
Picea (n = 28)	16	12	23	5
Pinus (n = 22)	15	7	11	11
Tilia (n = 20)	9	11	17	3

View popup
Table 4.
TSS types observed on trees on public and private lands in Guelph, ON.
TSS types No. trees sampled
Metal stakes with a hose-covered wire 241
Wooden stakes with a hose-covered wire 35
Guy wires 15
No TSS observed 197
Total 488

View popup

Table 5.

Number of trees observed in Guelph, ON, displaying varying symptoms of health (from poor [1] to good [5]).

Symptoms	Numbers of trees
Symptoms	Score 1	Score 2	Score 3	Score 4	Score 5
Overall health	1	2	3	12	470
Crown dieback	2	8	26	31	421
Girdled trunk	9	6	21	49	403
Pests/diseases	0	4	26	4	454
Swelling	7	5	4	4	468
Leaf scorch	0	4	26	49	409
Wilting	0	0	1	5	482
Stunted growth	1	0	2	5	480
Flagging	0	0	0	0	488
Suckering	6	3	4	18	457

Note: Values are interpreted in Table 1.

View popup
Table 6.
Results of comparisons of symptoms for all sampled trees with and without stabilization systems (Wilcoxon rank sum test, P = 0.05, n = 488).
Symptom P value
Overall health 0.0072 ^{^z}
Crown dieback 0.2878
Girdled trunk 0.0158y
Swelling <0.0001^{^y}
Pest/disease <0.0001^{^z}
Leaf scorch 0.0637
Wilting <0.0001 ^{^y}
Stunted growth 0.0581 ^{^x}
Suckering 0.2330
↵^zSignificantly (P = 0.05) less severe on trees observed with a tree stabilization system.
↵^ySignificantly (P = 0.05) more severe on trees observed with a tree stabilization system.
↵^xSignificantly (P = 0.06) more severe on trees observed with a tree stabilization system.

View popup

Table 7.

Results of comparisons of symptoms for sampled trees with and without stabilization systems, stratified by land ownership (Wilcoxon signed ranks test, P = 0.05; public n = 247, private n = 241).

Symptom	Mean values for public trees with TSS	Mean values for public trees without TSS	Public trees P value	Mean values for private trees with TSS	Mean values for private trees without TSS	Private trees P value
Overall health	5.00	4.78	<0.0001^{^z}	4.94	4.93	0.8855
Crown dieback	4.86	4.56	0.0005^{^z}	4.57	4.82	0.0259^{^y}
Girdled trunk	4.83	4.72	0.1979	4.30	4.78	0.0026^{^y}
Swelling	4.99	5.00	0.7729	4.45	4.98	<0.0001^{^y}
Pest/disease	5.00	4.74	<0.0001^{^z}	4.99	4.64	0.0004^{^z}
Leaf scorch	4.66	4.74	0.8048	4.80	4.84	0.1781
Wilting	4.97	4.88	<0.0001^{^y}	5.00	5.00	1.0000
Stunted growth	5.00	4.92	0.0003^{^z}	4.99	4.96	0.8003
Suckering	4.99	4.92	0.0408^{^z}	4.72	4.82	0.5754

↵^zSignificantly (P = 0.05) less severe on trees observed with a tree stabilization system.
↵^ySignificantly (P = 0.05) more severe on trees observed with a tree stabilization system.
Note: Trees on private land have no known warranty inspection and are maintained by private staff or contractor. Trees on public land have a warranty inspection at 24 months and removal of TSS is required. Public trees are maintained by city staff.