Article Figures & Data
Figures
- Figure 1.
Adaptation of water displacement tub to assess root volume (Harrington et al. 1994). Roots were hung from center clip and allowed to float, unhindered in water. Water displaced was measured in pipette with use of magnifying glass. The system was calibrated three times before assessing root volumes, and each root system was assessed three times to obtain average volume.
- Figure 2.
Allometric relationship between mean tree transpiration and natural-log transformed saturated hydraulic conductivity; correlation generated with linear best-fit model with line equations and R2 values shown for each soil treatment.
MODERATE = mean bulk density for the three-year study of 1.64 g∙cm−3 (n = 24 soil samples and n = 28 transpiration measurements). HIGH = mean bulk density for the three-year study of 1.77 g∙cm−3 (n = 48 soil samples and n = 42 transpiration measurements). Each data point represents a mean of two sample soil cores taken from each lysimeter and the corresponding tree transpiration for the three-year study.
Tables
- Table 1.
Dry bulk density (ρb), aeration porosity, log-aeration porosity, total porosity, void ratio, saturated hydraulic conductivity (Ks), natural log-normalized saturated hydraulic conductivity [nLog(Ks)], and % (v/v) volumetric water content for compacted soils averaged over three-year study.
Soil treatmentz 2002–2004 mean soil variables MODERATE HIGH ρb (g·cm−3) 1.64 ± 0.02 b 1.78 ± 0.01 a Aeration porosity (%) 13 ± 1.2 b 16 ± 0.7 a Log-aeration porosity −0.94 ± 0.04 b −0.84 ± 0.02 a Total porosity (%) 38 ± 0.7 a 33 ± 0.3 b Void ratio (m3·m−3) 0.62 ± 0.02 a 0.50 ± 0.01 b Ks (cm·r−1)y 330.0 ± 113.8 a 21.5 ± 6.9 b nlog- Ks 3.47 ± 0.58 a 0.98 ± 0.30 b Volumetric water content (%, v/v)x 24 ± 0.02 a 16 ± 0.01 b ↵zMODERATE = mean bulk density for the three-year study of 1.64 g·cm−3 (n = 28 soil samples), HIGH = mean bulk density for the three-year study of 1.77 g·cm−3 (n = 56 samples).
↵ySaturated hydraulic conductivity (Ks) was measured in 2002 and 2003.
↵xVolumetric water content was determined for each sample from gravimetrie water content and bulk density measures; means ± mean standard errors followed by different letters indicate a significant difference between soil treatments, at P ≤ 0.05 (Tukey’s honestly significant difference test, HSD).
- Table 2.
Comparison of mean percent CO2, O2, and N2 gas samples taken biweekly in 2002 and 2003 from MODERATE-and HIGH-density soil treatments.
Soil gasz Soil treatmenty CO2 O2 N2 MODERATE-density 0.66 ± 0.05 a 19.0 ± 0.48 b 80.4 ± 0.56 a HIGH-density 0.21 ± 0.03 b 21.2 ± 0.10 a 78.7 ± 0.09 b ↵zGases were sampled during growing season of 2002 and 2003 and represent the mean for the three sample ports per pot.
↵yMODERATE= mean bulk density for three-year study of 1.64 g·cm−3 (n = 21 gas samples), and HIGH= mean bulk density for the three-year study of 1.77 g·cm−3. (n = 24 gas samples); means ± mean standard error followed by different letters indicate a significant difference between soil treatments, at P ≤ 0.05.
- Table 3.
Analysis of Variance (ANOVA) results showing significance for mean daily transpiration, daily transpiration per leaf area, leaf area, leaf dry weight, stem dry weight, caliper growth, height growth, root dry weight, root volume, and root:shoot ratio for two compaction treatments, two maple species, and three years, including interactions between soil treatment, species, and year.
Analysis of Variance Resultsz Speciesy Soil treatment Year Species soil treatment Species year* Soil treatment year* Water use measures Mean daily transpiration (mL) ns *** *** ns ** ** Mean daily transpiration per leaf area (mL·cm2) ns ** *** ns ns ns Biomass Measures Leaf area (cm2) ns * *** ns *** ns Leaf dry weight (g) ns * *** ns *** ns Stem dry weight (g) * *** * ns ns ns Caliper growth (cm·yr.−1) ns ns *** ns ns ns Height growth (cm·yr.−1) *** * * * ** ns Root dry weight (g) * ns *** ns ns ns Root volume (cm3) *** ns *** ns ns ns Root:shoot (ratio) ** * *** ns ns ns ↵zANOVA results indicate that asterisks (*, **, ***) represent statistical significance at P ≤ 0.05, P ≤ 0.01, P ≤ 0.001 levels; ns indicates not significant.
↵ySpecies Acer × freemanii ‘Armstrong’, Armstrong Freeman maple and Acer rubrum ‘Brandywine’, Brandywine red maple; the species by soil treatment by year interaction is not shown as it was insignificant for all measurements.
- Table 4.
Mean daily transpiration (mL·day−1) for interactions between main treatments of year by compaction treatment and year by species.
Mean daily transpiration (mL·day−1) Year byz / Soil treatmenty Year by / Speciesx 2002 2002 MODERATE-density 66.9 ± 8.3 a ‘Armstrong’ 19.0 ± 7.4 b (n = 14) (n = 21) HIGH-density 13.5 ± 6.9 b ‘Brandywine’ 43.6 ± 10.4 a (n = 28) (n = 21) 2003 2003 MODERATE-density 25.0 ± 6.3 a ‘Armstrong’ 11.4 ± 6.1 a (n = 10) (n = 15) HIGH-density 7.8 ± 3.2 b ‘Brandywine’ 15.6 ± 2.8 a (n = 20) (n = 15) 2004 2004 MODERATE-density 56.9 ± 11.4 a ‘Armstrong’ 65.7 ± 4.5 a (n = 4) (n = 6) HIGH-density 54.4 ± 8.1 a ‘Brandywine’ 44.8 ± 10.7 b (n = 8) (n = 6) ↵zYear study period was 2002, 2003, and 2004.
↵yMODERATE = mean bulk density for three-year study of 1.64 g·cm−3, HIGH = mean bulk density for the three-year study of 1.77 g·cm−3.
↵xSpecies were Acer × freemanii ‘Armstrong’, Armstrong Freeman maple, and Acer rubrum ‘Brandywine’, Brandywine red maple; sample sizes reflect the total number of trees available for sampling at the end of each year. At the end of 2002, 12 total trees were destructively harvested to determine stem weight and root growth. At the end of 2003, 18 total trees were destructively harvested, and at the end of the study, all remaining trees were harvested (n = 12); Means ± mean standard error followed by different letters indicate a significant difference between soil treatments at P ≤ 0.05 for each year. Differences between species were found only at P ≤ 0.10 (P = 0.06 in 2002, and P = 0.10 in 2004).
- Table 5.
Mean daily transpiration per leaf area (mL·cm−2) for year main treatment and soil treatment mean values averaged across 2002 to 2004.
Mean daily transpiration per leaf area (mL·cm−2) Yearz Soil treatmenty 2002 2002–2004 (n = 42) 0.01 ± 0.005 b MODERATE-density (n = 14) 0.03 ± 0.004 a (n = 14) 2003 (n = 30) 0.01 ± 0.002 b HIGH-density 0.01 ± 0.004 b (n = 28) 2004 (n = 12) 0.06 ± 0.009 a ↵zYear study period was for 2002, 2003, and 2004.
↵yMODERATE = mean bulk density for three-year study of 1.64 g·cm−3, HIGH = mean bulk density for the three-year study of 1.77 g·cm−3; sample sizes for each year or compaction treatment are indicated in parenthesis; means ± mean standard error followed by different letters indicate a significant differences between mean daily transpiration per leaf area rate between years or soil treatments averaged across the three-year study period at P ≤ 0.05.
- Table 6.
Mean annual height growth, leaf area, and dry weight measurements for interactions between year by species and for species by soil treatment.
Biomass measure Height growth (cm·y−1) Leaf area (cm2) Leaf dw (g) Year by specieszy 2002 (n = 21) ‘Armstrong’ 27.0 ± 3.8 a (a) 1167.4 ± 85.2 b (a) 9.2 ± 0.6 b (a) ‘Brandywine’ 30.1 ± 4.2 a [a] 2150.9 ± 137.1 a [a] 13.5 ± 0.9 a [a] 2003 (n = 15) ‘Armstrong’ 27.3 ± 4.4 a (a) 1429.2 ± 231.4 a (a) 10.3 ± 1.5 a (a) ‘Brandywine’ 11.6 ± 2.5 b [b] 1411.1 ± 105.9 a [b] 9.0 ± 0.7 a [b] 2004 (n = 6) ‘Armstrong’ 27.8 ± 5.7 a (a) 1041.1 ± 88.3 a (a) 8.0 ± 0.6 a (a) ‘Brandywine’ 6.1 ± 4.2 b [b] 860.3 ± 50.6 a [c] 6.5 ± 0.4 a [c] Species by soil treatmentx ‘Armstrong’ MODERATE-density (n = 14) 40.1 ± 4.3 a (a) 1577.0 ± 241.0 a (a) 11.8 ± 1.5 a (a) HIGH-density (n = 28) 20.8 ± 2.4 b [a] 1075.8 ± 61.9 b [b] 8.2 ± 0.4 b [b] ‘Brandywine’ MODERATE-density (n = 14) 21.8 ± 4.7 a (b) 1972.0 ± 224.2 a (a) 12.3 ± 1.5 a (a) HIGH-density (n = 28) 19.2 ± 3.5 a [a] 1567.5 ± 113.1 a [a] 10.2 ± 0.6 a [a] ↵zYear study period was 2002, 2003, and 2004.
↵ySpecies were Acer × freemanii ‘Armstrong’, Armstrong Freeman maple, and Acer rubrum ‘Brandywine’, Brandywine red maple; means ± mean standard error followed by different letters indicate a significant difference between treatments, at P ≤ 0.05 (Tukey’s honestly significant difference test, HSD); values in parentheses indicate differences within a single species but between year or soil treatment, and means in brackets indicate differences within either a single year and between species, or a single species between soil treatments.
↵xMODERATE = mean bulk density of 1.64 g·cm−3 (n = 24), HIGH = mean bulk density of 1.77 g·cm−3 (n = 48) averaged across the three-year study.
- Table 7.
Mean stem dry weight, root dry weight, root volume, and root:shoot ratio are indicated for each soil treatment, each maple cultivar, and each year.
Biomass measure Stem dry wt (g) Root dry wt (g) Root volume (cm3) Root:shoot (ratio) Soil treatmentz MODERATE-density (n = 14) 23.7 ± 2.4 a 45.7 ± 6.4 a 100.1 ± 15.2 a 1.3 ± 0.13 b HIGH-density (n = 28) 15.2 ± 1.2 b 36.7 ± 3.8 a 78.6 ± 9.6 a 1.5 ± 0.11 a Speciesy ‘Armstrong’ Freeman maple (n = 21) 15.3 ± 1.9 b 32.7 ± 4.5 a 64.5 ± 10.1 b 1.3 ± 0.10 b ‘Brandywine’ red maple (n = 21) 20.8 ± 1.4 a 46.7 ± 4.5 a 107.0 ± 11.2 a 1.5 ± 0.14 a Yearx 2002 (n = 12) 13.6 ± 1.9 b 18.4 ± 2.6 b 67.9 ± 12.8 b 0.72 ± 0.04 c 2003 (n = 18) 19.0 ± 2.2 a 43.5 ± 5.0 a 108.3 ± 15.4 a 1.49 ± 0.07 b 2004 (n = 12) 20.9 ± 1.9 a 55.3 ± 3.9 a 142.7 ± 10.6 a 1.98 ± 0.11 a ↵zMODERATE = mean bulk density of 1.64 g·cm−3 (n = 24), HIGH = mean bulk density for the three-year study of 1.77 g·cm−3 (n = 48).
↵ySpecies Acer × freemanii ‘Armstrong’, Armstrong Freeman maple, and Acer rubrum ‘Brandywine’, Brandywine red maple; means ± mean standard error followed by different letters indicate a significant difference between soil treatments, species, or year at P ≤ 0.05.
↵xYear study period was 2002, 2003, and 2004.
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