A. Tree Physiology

Slide 1 Tree Physiology LHAP 305 – Urban Forestry and Arboriculture Slide 2 What is Urban Forestry? The collection of all trees, woody plants, and vegetation in an urban center. It includes planning, planting, maintaining, removal, and protection. Urban foresters – Serve communities by maintaining and improving the environment using trees and other woody plants. Managing the costs and risks of having trees in the urban environment. Slide 3 What is Arboriculture? The practice and study of care, of trees and other woody plants ISA International Society of Arboriculture Has different chapters all over the world Alberta, Saskatchewan, and Manitoba is part of the Prairie Chapter They promote the world of Arboriculture They control the process of becoming a certified arborist Slide 4 Tree Defects The Three D’s –Dead, Damaged, Diseased Cracks Cankers Co-Dominate Stems Included Bark Girdling Roots Ramshorning Trimmer Damage Poor pruning practices Total Landscape Care. (2024, April 24). Caring for hazardous trees: Identifying problems and reducing risks. Total Landscape Care. Retrieved Oct 18, 2025 Slide 5 Dead, Damaged, Diseased Dead Damaged Diseased Included in Pruning Plan Tree people. (2018, June 27). The 4 D’s: Dead, Diseased, Damaged, or Deranged! Tree People. Retrieved Oct 18, 2025 Slide 6 Cracks Horizontal cracks Vertical Cracks Degiovanni, J. (2013, April 30). Any way to save a large tree that's starting to split/crack down the middle? Gardening and Landscaping. Retrieved Oct 18, 2025 Beswick Tree Service. (n.d.). My TreeHas a Crack in It - What Should I Do? Beswick Tree Service. Retrieved Oct 18, 2025 Slide 7 Cankers Dead wood and Bark Sunken discoloured appearance Oozing sap Trees by Jake. (n.d.). Tree Cankers. Trees by Jake. Retrieved Oct 18, 2025 Slide 8 Co-Dominate Stems 2 stems of close to equal diameter both trying to be the dominant stem The union will have included bark Moore Cuts Florida. (2024, July 24). Understanding Co-Dominant Stems in Trees & Their Associated Risks. Moore Cuts Florida. Retrieved Oct 18, 2025 Slide 9 Girdling Roots Roots rap around the tree trunk and inhibit its growth and causes a weak point at ground level Iowa State University. (2024, July). How to Manage Trees Near Sidewalks. Iowa State University. Retrieved Oct 18, 2025 Slide 10 Rams Horning When a tree is sealing off a wound it can grow in a “in-curling form” Keslick, J. (n.d.). Oak. Keslick and Son Modern Arboriculture. Retrieved Oct 18, 2025 Slide 11 Trimmer Damage Damage to the base of the trunk from string trimmers getting too close and cutting into the wood Robson, D. (2016, June 06). Mower and Weed Eater Damage. Home, Yard, and Garden Pest. Retrieved Oct 18, 2025 Slide 12 Poor Pruning Practices Untrained people doing their own pruning Humans tend to like to break branches and leave those open wounds American Climbers. (2024, Dec 09). 9 Common Pruning Mistakes that Could Kill your Metrowest Trees. American Climbers. Retrieved Oct 18, 2025 American Climbers. (2024, Dec 09). 9 Common Pruning Mistakes that Could Kill your Metrowest Trees. American Climbers. Retrieved Oct 18, 2025 Slide 13 Tree Roots – They follow the water Lateral Roots – Grow outwards. Tap Roots – Grow down. Root hairs Root Flare Mycorrhizae – symbiotic relationship with roots Huang, S. (n.d.). 3 Types of Tree Root Systems. A-Plus Tree Care and Sustainability. Retrieved Oct 18, 2025 Slide 14 Root Development site constraints Compaction Underground Barriers Soil type Poor Planting Practices Iowa State University. (2024, July). How to Manage Trees Near Sidewalks. Iowa State University. Retrieved Oct 18, 2025 Slide 15 Tree Hormone Cycles Seasonal Changes – due to Light and temperature changes https://www.pathwayz.org/Tree/Plain/PLANT+HORMONES Slide 16 Tree Hormone Cycles Gibberellins- Germination and Growth Auxins - Growth Regulator Cytokinin's- Promote Cell Division Ethylene- Causes fruit ripening and leaf drop (Senescence) Abscisic Acid – Inhibits Germination and Growth Pathwayz. (n.d.). Plant Hormones. Pathwayz. Retrieved Oct 18, 2025 Slide 17 CODIT – Trees Defence System Compartmentalization of Decay in Trees Trees do not HEAL, they SEAL It uses 4 walls to contain the decay Tylosis- When parenchyma cells “balloon” and block flow of sap. First line of defense against decay. Eastside Tree Works. (2013, Feb 09). Recognizing Hazard Trees #1 CODIT. Eastside Tree Works. Retrieved Oct 18, 2025 Slide 18 CODIT Wall 1 Weakest of the 4 walls Works to contain the decay from spreading up and down the trunk into the roots or shoots Blocks off the Xylem above and below the wound Wall 2 Second Weakest Works to contain the decay from spreading inwards towards the center Closes off the latewood cells Slide 19 CODIT Wall 3 Prevents the decay from spreading around the tree (Laterally on horizontal plane) Blocks the decay using Ray cell in the trunk. Wall 4 The Strongest wall Blocks Decay from spreading outwards into the new wood that is formed after the injury Slide 20 Which wall(s) failed and held in these examples Auro. (2012, Feb 15). File:CODIT example 1 - Auró.JPG. Wikimedia Commons. Retrieved Oct 18, 2025 PennState. (2024, Nov 10). Understanding the Spread of Decay in Trees. PennState Extension. Retrieved Oct 18, 2025 PennState. (2024, Nov 10). Understanding the Spread of Decay in Trees. PennState Extension. Retrieved Oct 18, 2025 Slide 21 Ring Porous and Diffuse porous Ring Porous -distinct earlywood and latewood vessels -high conductivity in early wood - Quercus, Fraxinus, ulmus, Hippophae Diffuse porous Vessels more evenly distributed Moderate conductivity year-round Acer, Betula, Tilia, populus, salix, cornus, aesculus Slide 22 Tree Morphology – Tree Structure Includes looking at the Trunk, Branches, Leaves, and roots. Is anything wrong with any of them? Meriam Webster. (n.d.). Structure of a Tree. Meriam Webster. Retrieved Oct 18, 2025 Slide 23 Trunk Damage to the trunk Bends in the wood Leaning Boring Holes Peeling Bark Oozing liquids Co-Dominance Slide 24 Branches Dead, Damaged, Diseased Rubbing Branches Co-Dominant Slide 25 Leaves Discolouration Insect damage – Leaf Miner Early Leaf drop Slide 26 Roots Decaying Damaged Girdling Slide 27 Bibliography American Climbers. (2024, Dec 09). 9 Common Pruning Mistakes that Could Kill your Metrowest Trees. American Climbers. Retrieved Oct 18, 2025, from https://americanclimbers.com/pruning-mistakes/ Auro. (2012, Feb 15). File:CODIT example 1 - Auró.JPG. Wikimedia Commons. Retrieved Oct 18, 2025, from https://commons.wikimedia.org/wiki/File:CODIT_example_1_-_Aur%C3%B3.JPG Beswick Tree Service. (n.d.). My Tree Has a Crack in It - What Should I Do? Beswick Tree Service. Retrieved Oct 18, 2025, from https://beswicktreeservice.com/article/my-tree-has-a-crack-in-it-what-should-i-do Degiovanni, J. (2013, April 30). Any way to save a large tree that's starting to split/crack down the middle? Gardening and Landscaping. Retrieved Oct 18, 2025, from https://gardening.stackexchange.com/questions/24421/any-way-to-save-a-large-tree-thats-starting-to-split-crack-down-the-middle Eastside Tree Works. (2013, Feb 09). Recognizing Hazard Trees #1 CODIT. Eastside Tree Works. Retrieved Oct 18, 2025, from https://www.eastsidetreeworks.com/blog/recognizing-hazard-trees-1-c-o-d-i-t/ Huang, S. (n.d.). 3 Types of Tree Root Systems. A-Plus Tree Care and Sustainability. Retrieved Oct 18, 2025, from https://aplustree.com/3-types-of-tree-root-systems/ Iowa State University. (2024, July). How to Manage Trees Near Sidewalks. Iowa State University. Retrieved Oct 18, 2025, from https://yardandgarden.extension.iastate.edu/how-to/how-manage-trees-near-sidewalks Keslick, J. (n.d.). Oak. Keslick and Son Modern Arboriculture. Retrieved Oct 18, 2025, from http://treedictionary.com/DICT2003/HTMLFILES/disscoloredwood-4.htm Meriam Webster. (n.d.). Structure of a Tree. Meriam Webster. Retrieved Oct 18, 2025, from https://www.visualdictionaryonline.com/plants-gardening/plants/tree/structure-tree.php Moore Cuts Florida. (2024, July 24). Understanding Co-Dominant Stems in Trees & Their Associated Risks. Moore Cuts Florida. Retrieved Oct 18, 2025, from https://moorecutsflorida.com/tree-tidbits/f/understanding-co-dominant-stems-in-trees-their-associated-risks Pathwayz. (n.d.). Plant Hormones. Pathwayz. Retrieved Oct 18, 2025, from https://www.pathwayz.org/Tree/Plain/PLANT+HORMONES PennState. (2024, Nov 10). Understanding the Spread of Decay in Trees. PennState Extension. Retrieved Oct 18, 2025, from https://extension.psu.edu/understanding-the-spread-of-decay-in-trees#:~:text=In%20the%201970s%2C%20USDA%20Forest,such%20as%20foresters%20and%20arborists. Robson, D. (2016, June 06). Mower and Weed Eater Damage. Home, Yard, and Garden Pest. Retrieved Oct 18, 2025, from https://hyg.ipm.illinois.edu/article.php?id=808 Total Landscape Care. (2024, April 24). Caring for hazardous trees: Identifying problems and reducing risks. Total Landscape Care. Retrieved Oct 18, 2025, from https://www.totallandscapecare.com/business/article/15042541/identifying-and-caring-for-hazardous-trees Tree people. (2018, June 27). The 4 D’s: Dead, Diseased, Damaged, or Deranged! Tree People. Retrieved Oct 18, 2025, from https://treepeople.org/2018/06/27/dead-diseased-damaged-deranged/ Trees by Jake. (n.d.). Tree Cankers. Trees by Jake. Retrieved Oct 18, 2025, from https://treesbyjake.com/tree-cankers/