Arboriculture & Urban Forestry 42(3): May 2016 139 Figure 5. Relationship between length of annual growth and number of years elapsed since the last pruning episode. The solid line represents the regression line of the annual response growth, while the dotted line represents the regression line of the annual control growth. Linear regression of annual length on time with species interaction yielded; R 2 734. Fraxinus pennsylvanica, R 2 saccharinum, R 2 = 0.169, P < 0.001, slope = -0.18 N = = 0.01, P < 0.05, slope = -0.03, N = 369; A. platanoides, R 2 = 0.05, P < 0.005, slope = -0.07, N = 278; A. = 0.005, P > 0.05, slope = -0.02, N = 252. Control growth statistics not reported. mum length growth was generally found dur- ing the first year following pruning and reached approximately 1.5 m for all three species (Figure 5). Assessment of Branch Growth Predictors Of all the branch growth predictors tested, only a few showed significant relationships with re- growth rate. The correlation table (Table 3) lists respective variable relationship strength. In each case, the relationships with the species pooled were first tested (across all species data pooled together), and then separately within species. Across all species pooled, directional prun- ing growth was significantly different from both epicormic growth and heading cut growth (Tukey’s HSD test P < 0.001) and resulted in the slowest branch growth following pruning, there was no significant difference between heading and epicormic growth. Within each species, results from the Tukey’s test varied slightly (Figure 6), for A. platanoides direc- tional pruning was significantly different (P < 0.001) from both epicormic growth and head- ing cut growth, while epicormic growth and heading cut growth response was not signifi- cantly different. In the case of A. saccharinum, each type of response was significantly dif- ferent (P < 0.05), while for F. pennsylvanica only heading growth was significantly dif- ferent from the other two groups (P < 0.05). length on inclination while testing for species interaction yielded R 2 N = 338, P < 0.001; A. platanoides, R 2 The linear regression analysis of annual = 0.11 F (5,729) = 18.8, P < 0.001, slope = 0.002, N = 730. Within each species the results are as follows; F. pennsylvan- ica, R 2 (1,208) = 35.54, P < 0.001, slope = 0.008, N = 209; A. saccharinum, R 2 = 0.007, F (1,188) = 1.46, P > 0.05, slope = -0.002, N = 189 (Figure 7). Height of the origin of regrowth had a weak neg- ative correlation with regrowth rate in A. sacchari- num [R 2 = 0.04, F (1,188) = 7.81, P < 0.05, slope = -0.05, N = 189], where growth originating higher on the tree was typically shorter than growth origi- nating lower on the tree, but the relationship was not significant or very weak in the other species [F. pennsylvanica, R 2 slope = -0.004, N = 338; A. platanoides, R 2 = 0.0003, F(1,337) = 0.11, P < 1.0, = 0.02, F(1,204) = 3.99 , P < 0.05, slope = -0.06, N = 205]. Of the tree size variables investigated, only parent stem diameter (the size of the limb the regrowth originated from) showed significant results (P < 0.001), pooled species R 2 F(1, 733) = 20.56, P < 0.001, slope =0.005, N = 734), and only A. saccharinum showed a sig- nificant relationship between stem diameter and regrowth (R 2 = 0.02, = 0.06, F (1,188) = 13.28, P < 0.001, slope = 0.007, N = 189). The other species showed no significant relationship between stem or tree size and response growth rate (Table 3). ©2016 International Society of Arboriculture = 0.07, F (1,337) = 27.44, slope = 0.003, = 0.14, F
May 2016
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
