76 Gilman et al.: Effect of Container Type and Root Pruning on Growth and Anchorage Aſter Planting December 2013. Weeds were controlled with pe- riodic application of glyphosate to mulch surface. Trees planted into the landscape as liners and under the crown. Trees planted from liners, #3, and #15 containers received 300 g (20 N - 0 K2 from #3 containers received 226 g fertilizer (12 N - 2 K2 [1] O - 14 P2 planted from liners, #3, #15, and #45 containers received 400 g (20 N - 0 K2 April and July 2012, and April 2013. Trees were not pruned aſter planting other than to remove twigs and small branches that drooped in the way of the mower used to periodically cut surface vegetation. - 8 P2 ) in March and 400 g in May 2010. Trees O - 8 P2 O5 O5 ) in June 2011, Evaluating Post-Planting Anchorage and Growth Trees from liners #3, #15, and #45 container sizes were winched due north to five degrees trunk tilt from vertical start position to evaluate anchorage 26 months aſter landscape planting. This began June 2010 for the ten trees planted from liners that represented the mean trunk diameter of the 40 planted. In May 2011, trees from #3 containers were winched (one or two blocks each rain-free day) with an electric winch attached to a cable about 1.2 m from the ground. The cable remained parallel to ground. A 3629 kg capacity load cell (SSM-AF-8000; Interface Inc., Scottsdale, Ari- zona, U.S.) was placed in-line with the winching cable. An inclinometer (model N4; Rieker Inc., Aston, Pennsylvania, U.S.) was mounted to a fab- ricated steel plate (5.1 × 7.6 cm). The plate was secured to the trunk base 15 cm from soil sur- face which was just above the swollen flare at the trunk base. Cable was winched at 2 cm·sec-1 until the inclinometer tilted five degrees from vertical start position; tree was held for 60 seconds before allowing cable to release. Sixty seconds follow- ing cable release, final angle at the trunk base was recorded as rest angle. Trees from #15 and #45 containers were also winched 26 months aſter landscape installation in the manner described. Data from load cell and inclinometer were collected at 2 Hz by Data Acquisition System (National Instruments Corporation, Austin, Texas, U.S.) and recorded on a laptop. Data during pull- ing tests were displayed in real-time on a lap- top running LabView soſtware (v: 7.0; National ©2016 International Society of Arboriculture O5 ) in May 2009, spread evenly O [1] 𝜎𝜎蟫 = 𝐹𝐹蟫 ∙ 𝑑𝑑蟫 ∙ 𝑅𝑅蟫 𝜋𝜋蟫 4 ∙ 𝑅𝑅蟫 4 where σ = bending stress; F = pulling force; d = distance from pulling point to inclinometer; and R = trunk radius (calculated as halv- ing diameter measured with a diameter tape). In March 2014, an air excavation device removed soil from the top 10 cm of the soil pro- file within a 50 cm radius around each trunk to measure roots on 24 (#3) + 48 (#15) + 80 (#45) + 10 (liners) = 162 planted trees. Root measure- ments included: 1) one visual rating, conducted by two individuals, of the imprint on the root system (1 = no imprint; 5 = large imprint with many roots kinked, circling, descending, and/or ascending) from root deflection at any container size (#3, #15, or #45), excluding the original prop- agation container; and 2) diameter of the ten larg- est roots measuring 5 cm beyond the edge of the planted root ball (five in the northern and five in the southern 90 degree quadrants) in the top 10 cm soil profile. Root diameter was converted to cross-sectional area (CSA). Trunk diameter was measured at planting and each October thereafter. Experimental Design and Statistical Analysis Trees of each container size (liners, #3, #15, and #45) were planted in a separate randomized complete block design in four adjacent plots of the same field and soil type. Responses from #3 containers types were analyzed with one-way analysis of variance (ANOVA), and the main effect container with Tukey’s multiple type means were range separated test. Responses from #15 and #45 were analyzed with two-way ANOVA, and means for the main effects con- tainer type and root pruning were compared using Tukey’s; interaction means were com- pared using LSD. Pearson’s correlation coeffi- cient was used to compare imprint rating with top diameter of containers. The GLM procedure was used to calculate regression coefficients for predicting bending stress from trunk angle. Instruments, Austin, Texas, U.S.). Trunk bend- ing stress was calculated according to Equation 1.
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