Pruning Young Trees: Success Stories Start at Planting MPSTMA Fall Workshop November 14, 2018 Chad P. Giblin Department of Forest Resources -
|
|
|
- Kory Copeland
- 5 years ago
- Views:
Transcription
1 Pruning Young Trees: Success Stories Start at Planting MPSTMA Fall Workshop November 14, 2018 Chad P. Giblin Department of Forest Resources - University of Minnesota
2 Prune em like I used to!
3
4 Here s the Plan Pruning Cycles Pruning at Planting Basics of Developmental Pruning How-To Permanent Canopy Leader Management Managing Defects Temporary Branches Case Studies
5 Pruning Cycles
6 Young Tree Pruning Cycles Typical Pruning Cycles 3 to 10 years for Small Trees Valley Forge, Princeton, Autumn Blaze Every 2 to 3 years for 10 Years is IDEAL If greater Plan on losses and lower permanent canopy and smaller trees Pruning at planting works!
7
8
9 The Cost of Waiting Every Year Every Two Years Every Three Years
10 Pruning Every Three Years May Mean Removing up to 50% of Crown Volume Each Time Cycles Over Three Years? Crown Volume May Increase Exponentially Until Failure
11 4 Years 9 Years 6 Years 4 Years
12 Pruning at Planting
13 Pruning Acer rubrum at Planting Impacts Structure and Growth After Three Growing Seasons Edward F. Gilman Arboriculture & Urban Forestry 41(1): Pruning at planting is good or bad? Horticulture says, Bad! Forestry says, Good! Pruning at planting reduced stem caliper Temporary branch growth suppressed Reduction in included branches and size
14 Pruning at Planting the easiest and SAFEST time to prune!
15 Developmental Pruning
16 Permanent Canopy Shade trees on streets: 12 to 14 feet. Parks and yards, can be lower High-Canopy Shade Crown begins above 12 feet Often extend above 20 to 24 feet. These trees easily clear utility lines to reveal and complement architecture
17 High Canopy Shade
18 Shades a Couple of Windows Maybe
19 Leader Management Select the most vigorous and upright leader Sometimes there are MANY in young trees If there are co-dominant leaders do your best to choose only one
20 Rounded-Over Princeton - Multiple Leaders
21 Branch clusters, Included Branches and Defects These branches weaken as they grow Can cause major failures Lack structural integrity No place in the mature crown Prompt removal is necessary
22 Too Many Branches in Too Small a Space
23 How Long Before this Tree Splits in Two?
24 Temporary Branches Any branch below the mature crown They build a strong trunk when small Contribute to stem taper Remove before they are 50% size of stem
25 Thinning Cuts
26 Take em Off Small Because
27 Sooner or Later They Have to Come Off
28 Branch Union Morphology Affects Decay Following Pruning E. F. Gilman and J. C. Grabosky Arboriculture & Urban Forestry 32(2): March 2006 In cases where branch collars were not readily apparent, the cut was made from just outside the branch bark ridge perpendicularly through the branch.
29 Branch Union Morphology Affects Decay Following Pruning E. F. Gilman and J. C. Grabosky Arboriculture & Urban Forestry 32(2) In earlier studies, this technique resulted in little cambial dieback on the trunk beneath the cut (Eisner et al. 2002a) a (branch protection zone) BPZ can form even in the presence of a bark inclusion.
30
31 Reduction Cuts
32 Pole Pruners Prune Quickly and Safely from the Ground
33
34
35 Multiple Points of Suppression Help Slow Down Vigorous Temporary Branches
36
37 Pruning Severity and Crown Position Influence Aspect Ratio Change Edward F. Gilman Arboriculture & Urban Forestry 41(2): Pruning severity = 0, 25, 50 and 75% of branch removed Pruning can affect the overall growth of the tree Less pruning = more growth, in general Less pruning = more defects, in general Pruning severity decreases branch aspect ratio Lower branches need more pruning to suppress than higher
38 Structural Pruning Effects on Stem and Trunk Strain in Wind Edward F. Gilman, Jason W. Miesbauer and F.J. Masters Arboriculture & Urban Forestry 41(1): Codominant stems are targets for failure during windloading events Pruning back these codominant stems reduces the strain on the branch More pruning = more strain reduction Developmental pruning benefits trees with developing canopy Structural pruning benefits trees with permanent structural canopy
39 Temporary Branch Removal
40 Time to Remove Temporary Branches
41 A New Tree Biology Alex L. Shigo Shigo & Tree, Associates, 1989 When the hand saw was the major tool for pruning, most cuts were proper.
42
43
44
45
46
47
48
49
50 Case Studies
51 Autumn Blaze Freeman Maple Acer x freemanii
52 Lots of Potential: Manage it Wisely
53
54 Too Late??
55 Leader Management: Codom Removal
56 Suppression Cuts
57
58 Young Tree with a Bright Future
59 Primed for Success
60 and with Red Fall Color!
61 2017
62 2017
63 2018
64 2018
65 Cathedral Elm Ulmus davidiana var. japonica x U. pumila
66
67
68
69
70
71
72
73 Greenspire Littleleaf Linden Tilia cordata
74
75 Thinning Cuts
76
77
78
79
80
81
82
83
84
85
86 Reduction Cuts
87
88
89
90
91
92 Contacts & Links Chad Giblin Urban Forestry Outreach, Research & Extension (UFore) Nursery and Lab trees.umn.edu
93 Thanks! Environment & Natural Resource Trust Fund Minneapolis Park & Recreation Board City of Saint Paul Parks & Recreation Minnesota Turf & Grounds Foundation Minnesota State Capitol