ISA Arborist Certification Training - Chapter 1 - Tree Biology PDF
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Uploaded by AmbitiousSolarSystem
Kwantlen Polytechnic University
2015
Ben Reynoso & Eva Saunders
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Summary
This document provides a detailed introduction to tree biology, covering topics such as tree structure, function, and interrelationships. It explores the different types of trees, tree form, plant growth, and the various components of trees like bark, xylem, phloem, leaves, and roots. The document also mentions the functions of each part and includes diagrams.
Full Transcript
ISA Arborist Certification Training Chapter 1 – Tree Biology Illinois Arborist Association Arborist Certification Training September 1, 2015 Presented by: Ben Reynoso & Eva Saunders What is Tree Biology...
ISA Arborist Certification Training Chapter 1 – Tree Biology Illinois Arborist Association Arborist Certification Training September 1, 2015 Presented by: Ben Reynoso & Eva Saunders What is Tree Biology? The study of tree structure, the function of those structures and the interrelationship between both. Photo Credit: Mark Duntemann What is a Tree? Long-lived perennial Woody Compartmentalizing organism Photo Credits: Mark Duntemann Types of Trees Deciduous (oaks, maples, ash) Deciduous Conifer Photo Credits: Mark Duntemann (larch, baldcypress) Coniferous (pines, spruces, firs, junipers, yews) Tree Form Excurrent trees: Strong central lead Most young trees Conifers, sweet gum Graphic: Urban Tree Foundation Photo Credit: Missouri State University Tree Form Decurrent trees: Lateral shoots outgrow original terminal shoot Round-headed tree Typical of mature trees Oaks, elms Graphic: Urban Tree Foundation Plant Growth – Cellular Level Cell growth: A. Mitosis - cell division B. Cell differentiation 1. Cells change structure to specific function 2. Arranged tissues organized into organs (leaves, stems, roots, flowers and fruit) Photo: University of Wisconsin 3. Organs organized to function as an organism-tree. Tree Growth Cells & Tissues (GROWTH) Meristems – Cells that produce other cells Differentiation – Change in the cells structure to assume a needed function Apical meristems – Meristems located at the ends of shoots/buds and roots (primary growth) Cambium – Lateral Meristems that produce the tree’s vascular system (secondary growth) Cork Cambium – lateral meristem that produces bark Tree Growth Meristem is the tree growth zone Primary meristem: Responsible for elongation of roots and stems Located in the tips of roots and stems (buds) Graphic: Michigan State University Extension Tree Growth Secondary or Lateral Meristem: Increase in diameter Vascular cambium: produces xylem or phloem Cork cambium - produces bark Photo: UF Herbarium Growth Tissue: Cambium Where growth occurs Cambium produces: Phloem (outside) Xylem (inside) Graphic: UF Horticulture Tree Anatomy Vocabulary Cambium produces Xylem and Phloem Xylem – Is produced on the inside of the Cambium, it is the ‘wood’ of the tree. Moves water and minerals up to the leaves, supports the tree and stores sugars. Phloem – Is produced to the outside of the Cambium. It moves sugars down from the leaves Tree Anatomy Heartwood Non-water conduction Non-living xylem Sapwood Water conduction Living xylem Cambium Thin layer of active Graphic: Colorado State University Extension Xylem & Phloem Bark Vascular Tissue - Xylem Xylem is the wood of trees Functions: Conduction of water & dissolved minerals Support weight of tree Storage of carbohydrate reserves Defense against spread of disease & decay Vascular Tissue - Xylem Composed of dead & living cells Tracheids – water conduction & support Fibers – mechanical strength Parenchyma cells-help maintain water balance & store carbohydrates Vessels – hardwood trees Graphic: Sonoma State University Vascular Tissue - Xylem Transportation of water and minerals Transpiration is the loss of water through leaves Water molecules are pulled in long, hydrogen- bonded chains from root to leaf Graphic: University of Washington Vascular Tissue - Xylem Water conduction occurs in sapwood Conifers – 2-12 rings may conduct water Hardwoods – outermost 1 or 2 rings especially elm trees Non-water conduction – heartwood (darker in color than sapwood) Graphic: University of Minnesota Extension Vascular Tissue: Phloem Food transport Cells are living Sieve cells (conifers) Sieve tube cells Companion cells Parenchyma cells Graphic: Pacific Union College Vascular Tissue - Phloem Translocation: conduction of sugars produced in the leaves to other parts of the plant Photosynthate moves from source to sink Sinks – plant parts that use more energy than they produce Graphic: UF Horticulture Axial transport – Vascular Tissue materials flow up and down Radial Transport – parenchyma cells that extend across (radial) xylem and phloem Transport sugars Store starch Restrict decay Bark Function: Moderates interior temperature Reduces water loss Protects against injury Composition: Nonfunctional phloem & corky tissues Contains wax and Photo: East Tennessee State University oil to minimize water loss Bark Lenticels are small openings that permit gas exchange Photo: Colorado State Extension Tree Organs Leaves Stems Roots Flowers Fruits Leaves Primary Purpose is Photosynthesis: Inputs: Carbon dioxide Water Light Outputs: Carbohydrates/sugar (Photosynthates) Graphic: Butler University Herbarium oxygen Leaves Stomata Control loss of water vapor (transpiration) Control gas exchange Guard cells Light, temperature, wind and humidity Open-day, Close- night Photo: University of Hawaii at Manoa Antitranspirant Sprays Artificially close stomata cells to prevent water loss during drought or dormant times. Reduces photosynthesis, cooling of leaves, and carbon dioxide uptake Leaves Fall foliage color: Triggered by short, sunny days with cool nights Sugar accumulates & chlorophyll breaks down Other pigments show: Anthocyanins: reds & purples Carotenoids: yellows, oranges & reds Photo: USDA Leaves Deciduous Trees Leaves lost are the result of cell changes and growth regulators Abscission zone at stem: Enable leaf drop in fall Protect leaf area against desiccation & pathogen entry Graphic: University of California Davis Modified Leaves Arid regions: Thick cuticle, leathery leaves and few stomata Succulent, water retaining leaves or dense hairy coverings Photo: Texas A&M Tree Parts - Stems Strongly attached underneath but weakly attached above Branch collar – layers of tissue, bulge around branch base Autonomous- function on own Photo: University of Florida (Horticulture) Tree Parts – Stem Anatomy Node - gives rise to leaves & buds Internode - distance between nodes Terminal bud - primary growth Terminal bud scale scar - start of new growth of current year Tree Parts - Buds 1. Terminal or apical buds - located at the end of a shoot 2. Lateral or axillary buds - located on the sides of the stems. Tree Parts - Buds 3. Adventitious buds arise from loss of primary bud 4. Epicormic shoots- When dormant buds sprout and grow Photo by Joseph O’Brien, USDA Forest Service Tree Parts - Roots Main Functions: Anchorage Storage Absorption Conduction Roots need water & air Photo: Louisiana State University for optimal growth Tree Parts - Roots Absorbing roots - Small, fibrous organs that grow at the ends of roots and found in top foot of soil Lateral or horizontal roots near surface Sinker roots - Grow vertically downward off lateral roots and are found w/in few feet of trunk Photo: University of Texas Tree Parts - Roots Most roots found in upper 1-12” of soil Taproot is a downward growing Wrong root in young trees Roots may extend 2-3 times the tree crown/canopy Root extent and directional growth Correct is the result of the tree’s environment rather than genetics Tree Parts - Roots Mycorrhizae - the symbiotic relationship of roots with certain fungi Symbiosis – both organisms benefit from the living arrangement Fungi get food & in turn aid roots in Photo: Iowa State University Extension absorption of water and minerals Tree Parts - Roots Water enters young roots or mycorrhizal roots by osmosis Osmosis requires fluid transport from higher concentration to lower concentration Reverse Osmosis: water movement from out of roots into soil Example: de-icing roads with salt increases (higher concentration in soil) Photo: Forestry Department South Australia Allelopathy Production and release of chemical substances by one species that inhibit the growth of other species of plants Flowers & Fruit Flower is reproductive structure of plant. Once pollinated, give rise to the fruit or seed. Tree Physiology Photosynthesis Process that converts light into sugar and starches Chlorophyll is the green/leaf pigment that absorbs sunlight. Chlorophyll is stored in chloroplast cells of leaves where photosynthesis takes place. Raw material required are carbon dioxide and water. Tree Physiology Respiration Energy made from photosynthesis is used Oxygen is needed Carbon dioxide and water are given off Tree able to survive in these situations? 1. Flooded roots 2. Defoliated leaves by caterpillars ENERGY IS RELEASED Tree Physiology Transpiration Loss of water through stomata: Helps cool leaf during hot times and aids water uptake in xylem Dependent on water, temperature, & humidity 90% water absorbed from roots are lost in leaves Tree Physiology Control of Growth and Development Plant growth limited by: Genetics Environment Plant hormones Auxin: Produced in shoots Alters crown growth Involved in tropisms Cytokinin: Produced in roots Shoot initiation and growth Photo: University of Nottingham, UK Tree Physiology Control of Growth and Development Hormones signal: Cell Division Cell Elongation Flowering Fruit Ripening Leaf Drop Dormancy Root Development Tree Physiology Control of Growth and Development Tropisms: Geotropism-gravity response Phototropism-light response Photo: University of Wisconsin Tree Physiology Compartmentilization CODIT (Compartmentalization Of Decay In Trees) a system of defense. Graphic: USDA Forest Service Tree Physiology Compartmentilization Wall 1 resists vertical spread, plugs up xylem Wall 2 resists inward spread, plugs latewood cells Wall 3 inhibits lateral spread, activates rays cells to resist decay These 3 walls form reaction zone Tree Physiology Compartmentilization Wall 4 is the layer of wood to form after injury has occurred. Strongest of all 4 walls Protects from outward decay Barrier zone Photo: Colorado State Extension Palms Monocot Have no cambium layer Have no growth ring of xylem Have vascular bundles of xylem & phloem Photo: Smithsonian Marine Station, Ft. Pierce
