Illinois Chapter ISA Certification Workshop TREE BIOLOGY

1. Illinois Chapter ISA Certification WorkshopTREE BIOLOGY Chapter 1 Jennifer Hitchcock jenflwr@gmail.com

2. What is Tree Biology? The Study of Structure and Function of Trees And the Relationships between the two

3. Lecture Summary Tree Anatomy & Morphology The studies of the component parts of the tree (inside & out) Tree Physiology Study of the biological and chemical processes within the tree

4. What is a Tree? Long lived perennial Woody Compartmentalizing organism

5. Types of Trees Hardwoods e.g. oaks, maples, poplars, ash, beech, magnolia, locust, sycamore, sweet gum, willow, etc. Conifers (gymnosperms=naked seed) e.g. cypress, pines, spruces, firs, larches, junipers, yews Gingko

6. Excurrent tree: Strong central trunks (leaders) Most young trees Conifers, sweet gum

7. Decurrent tree: Lateral shoots outgrow original terminal shoot Round-headed tree Typical of mature trees Oaks, elms

8. Trees Main functions Grow Reproduce Maintain/ protect themselves

9. Tree Anatomy Heartwood (darker) Non-water conduction Non-living xylem Sapwood Water conduction Living xylem Cambium=growth Thin layer of active Xylem & Phloem Bark

10. Build a Tree

11. Plant Growth Cell growth: A. Mitosis - cell division B. Cell differentiation Cells change structure to specific function Arranged tissues organized into organs (leaves, stems, roots, flowers and fruit) Organs organized to function as an organism-tree!

12. Tree Anatomy Vocabulary 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

13. Tree Growth Meristem is the tree growth zone 1.Primary meristem– Responsible for elongation of roots and stems Located in the tips of roots and stems (buds)

14. Tree Growth 2. Secondary or lateral meristem – increase in diameter Vascular cambium – produces xylem or phloem Cork cambium - produces bark *Palms lack secondary or lateral growth (no increase in diameter size)

15. Tree Anatomy Vocabulary Cells & Tissues (GROWTH) 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. Stores sugars for future use. Made up of vessels (soda straws) Phloem – Is produced to the outside of the Cambium (next to the bark). It moves sugars down from the leaves

16. Growth Tissue: Cambium Where growth occurs (Growth rings –seasonal cambium) Cambium produces: Phloem (outside) Xylem (inside) The cambial zone or cambium is an area of dividing cells that differentiate into xylem (toward the inside) and phloem (toward the outside). It is on the move outward as the tree grows. Once xylem cells divide into their various components they can not move.The cambial zone or cambium is an area of dividing cells that differentiate into xylem (toward the inside) and phloem (toward the outside). It is on the move outward as the tree grows. Once xylem cells divide into their various components they can not move.

17. Vascular Tissue - Xylem Xylem=Wood of trees Functions: Conduction of water & dissolved minerals Support weight of tree Storage of carbohydrate reserves Defense against spread of disease & decay

18. Vascular Tissue - Xylem Composed of dead & living cells Xylem: Tracheids – water conduction & support Fibers – mechanical strength Parenchyma cells-help maintain water balance & store carbohydrates(example: ray cells) Vessels – hardwood trees only ( no gymnosperms) A tracheid and a vessel element, two types of water-conducting cells found in xylem tissue. Long chains of vessel elements connected end-to-end are called vessels. Pits in the walls allow water molecules to pass laterally through adjacent xylem cells, as a steady chain of water molecules moves upward through the xylem (vascular) tissue. Generally, most cone-bearing gymnosperm trees do not have vessels. Instead, their xylem tissue is composed primarily of tracheids. Gymnosperm wood is generally considered to be a close-grained softwood. Vessels perform most of the water conduction in hardwoods and are more efficient then tracheids. Both gymnosperm and angiosperm woods are converted into pulp for making paper products. An idealized plant system showing foliage, branch, stem and roots. At three levels, additional detail is shown within circles. Bottom close-up of the root showing the path of water movement from the soil particles to a root surface and into the root), middle (stem radial view with the bark to the outside, xylem with tracheids to the inside; between the xylem and the phloem is the cambium). A tracheid and a vessel element, two types of water-conducting cells found in xylem tissue. Long chains of vessel elements connected end-to-end are called vessels. Pits in the walls allow water molecules to pass laterally through adjacent xylem cells, as a steady chain of water molecules moves upward through the xylem (vascular) tissue. Generally, most cone-bearing gymnosperm trees do not have vessels. Instead, their xylem tissue is composed primarily of tracheids. Gymnosperm wood is generally considered to be a close-grained softwood. Vessels perform most of the water conduction in hardwoods and are more efficient then tracheids. Both gymnosperm and angiosperm woods are converted into pulp for making paper products. An idealized plant system showing foliage, branch, stem and roots. At three levels, additional detail is shown within circles. Bottom close-up of the root showing the path of water movement from the soil particles to a root surface and into the root), middle (stem radial view with the bark to the outside, xylem with tracheids to the inside; between the xylem and the phloem is the cambium).

19. 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 A tracheid and a vessel element, two types of water-conducting cells found in xylem tissue. Long chains of vessel elements connected end-to-end are called vessels. Pits in the walls allow water molecules to pass laterally through adjacent xylem cells, as a steady chain of water molecules moves upward through the xylem (vascular) tissue. Generally, most cone-bearing gymnosperm trees do not have vessels. Instead, their xylem tissue is composed primarily of tracheids. Gymnosperm wood is generally considered to be a close-grained softwood. Vessels perform most of the water conduction in hardwoods and are more efficient then tracheids. Both gymnosperm and angiosperm woods are converted into pulp for making paper products. An idealized plant system showing foliage, branch, stem and roots. At three levels, additional detail is shown within circles. Bottom close-up of the root showing the path of water movement from the soil particles to a root surface and into the root), middle (stem radial view with the bark to the outside, xylem with tracheids to the inside; between the xylem and the phloem is the cambium). A tracheid and a vessel element, two types of water-conducting cells found in xylem tissue. Long chains of vessel elements connected end-to-end are called vessels. Pits in the walls allow water molecules to pass laterally through adjacent xylem cells, as a steady chain of water molecules moves upward through the xylem (vascular) tissue. Generally, most cone-bearing gymnosperm trees do not have vessels. Instead, their xylem tissue is composed primarily of tracheids. Gymnosperm wood is generally considered to be a close-grained softwood. Vessels perform most of the water conduction in hardwoods and are more efficient then tracheids. Both gymnosperm and angiosperm woods are converted into pulp for making paper products. An idealized plant system showing foliage, branch, stem and roots. At three levels, additional detail is shown within circles. Bottom close-up of the root showing the path of water movement from the soil particles to a root surface and into the root), middle (stem radial view with the bark to the outside, xylem with tracheids to the inside; between the xylem and the phloem is the cambium).

20. 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)

21. Build a Tree

22. Vascular Tissue: Phloem Food transport (requires energy) Cells are living Sieve tube cells Companion cells Parenchyma cells *only sieve cells in gymnosperms

23. 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 All plant parts at one time are sinks Most photosynthate is either utilized or stored closed to manufacturing site a group of living cells that in woody plants is outside of the cambium (cambium is a meristematic tissue that produces xylem to the inside, that is the annual ring of wood growth) and phloem and bark to the outside. Sieve-tube members are associated with companion cells (see diagram below) and the sieve-tube member is responsible for moving food (from storage or photosynthesis) up and down the plant. a group of living cells that in woody plants is outside of the cambium (cambium is a meristematic tissue that produces xylem to the inside, that is the annual ring of wood growth) and phloem and bark to the outside. Sieve-tube members are associated with companion cells (see diagram below) and the sieve-tube member is responsible for moving food (from storage or photosynthesis) up and down the plant.

24. Vascular Tissue Axial transport – materials flow up and down (longitudinally) Rays – parenchyma cells that extend across (radial) xylem and phloem Transport sugars Store starch Restrict decay

25. Tree Bark Outer, protective covering Function: Moderates interior temperature Reduces water loss Protects against injury Composition: Nonfunctional phloem & corky tissues Contain wax and oil to minimize water loss Lenticels – small openings that permit gas exchange

26. Tree Organs Leaves Stems Roots Flowers Fruits-dry or fleshy

28. Leaf Anatomy Cuticle Vascular bundles Parenchmya cells -chloroplasts -chlorophyll Stomata Guard Cells Petiole Leaf blades have a large surface area for the absorption of sunlight and carbon dioxide needed for photosynthesis. Because leaves are thin, no cells are far from the surface. This structure facilitates the exchange of gases and absorption of light. Leaf blades have a large surface area for the absorption of sunlight and carbon dioxide needed for photosynthesis. Because leaves are thin, no cells are far from the surface. This structure facilitates the exchange of gases and absorption of light.

29. Leaves Primary Purpose: Photosynthesis Carbon dioxide Water Light Yields: Carbohydrates/sugar(Photosynthates) oxygen Leaf blades have a large surface area for the absorption of sunlight and carbon dioxide needed for photosynthesis. Because leaves are thin, no cells are far from the surface. This structure facilitates the exchange of gases and absorption of light. Leaf blades have a large surface area for the absorption of sunlight and carbon dioxide needed for photosynthesis. Because leaves are thin, no cells are far from the surface. This structure facilitates the exchange of gases and absorption of light.

30. Leaves Stomata – openings Control loss of water vapor (transpiration) Control gas exchange Guard cells – open and close stomata in response to: Light, temperature, wind and humidity Open-day Close-night Stomata – carbon dioxide is absorbed into the leaf, while oxygen and water vapor are released. Stomata – carbon dioxide is absorbed into the leaf, while oxygen and water vapor are released.

31. Antitranspirant Sprays Artificially close stomata cells to prevent water loss during drought or dormant times Reduces photosynthesis, cooling of leaves, and carbon dioxide uptake

32. Modified Leaves Arid regions: Thick cuticle, leathery leaves and few stomata Succulent, water retaining leaves or dense hairy coverings

33. Modified Leaves Tendrils Spines – reduce water loss and protect

34. Leaves Deciduous - trees that shed their leaves every year 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 An abscission zone is formed at the base of the leaf stalk or petiole. An abscission zone is formed at the base of the leaf stalk or petiole.

35. 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 Evergreen – trees that hold their leaves form more than one year

36. Branches Buds=Stems=Branches strongly attached underneath but weakly attached above Branch collar – layers of tissue, bulge around branch base Autonomous-function on own

37. 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 Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system. Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system.

38. 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.  *often dormant – because of apical dominance Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system. Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system.

39. Stems 3. Adventitious buds arise from loss of primary bud 4. Epicormic shoots-When dormant buds sprout and grow Environmental stress can trigger response Can grow from: Internode of the stem Edge of a leaf At the cut on a stem or root Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system. 'Adventitious' is a term used to describe structures that arise from unusual places, such as adventitious shoots that may arise from wounds, or adventitious roots that spring out of stems, or adventitious buds that form in places other than leaf axils. Adventitious structures are more common in the angiosperms. As an example, although aspen does not form adventitious or epicormic shoots on its stem, it does sprout prolifically from adventitious buds on the roots. This is how aspen clones come about (clones up to 81 ha in size are known). Such sprouting is stimulated by the removal of existing stems.Adventitious buds – Some tree species grow in groups in which individual trees have developed from adventitious buds on the roots, resulting in many trees having a common root system. 'Adventitious' is a term used to describe structures that arise from unusual places, such as adventitious shoots that may arise from wounds, or adventitious roots that spring out of stems, or adventitious buds that form in places other than leaf axils. Adventitious structures are more common in the angiosperms. As an example, although aspen does not form adventitious or epicormic shoots on its stem, it does sprout prolifically from adventitious buds on the roots. This is how aspen clones come about (clones up to 81 ha in size are known). Such sprouting is stimulated by the removal of existing stems.

40. Modified Stems Spur – a compressed stem with short internodes, usually bearing leaves, flowers and/or fruit. Many fruit trees such as apples, pears, cherries and ginkgo Thorn – pyracantha, locust

41. Roots 4 Main Functions: Anchorage Storage Absorption (sm roots) Conduction Roots need water & air for optimal growth

42. Roots Absorbing roots: Small, fibrous Grow at ends of roots Found in top foot of soil Lateral or horizontal roots near surface Sinker roots: Grow vertically downward off lateral roots Found w/in few feet of trunk

43. Roots Most roots found in upper 1-12” of soil Taproot is a downward growing root in young trees Roots may extend 2-3 times the tree crown/canopy Root extent and directional growth is the result of the tree’s environment rather than genetics Taproot is usually choked out by expansion of roots around it or is diverted from its downward growth by unfavorable growing conditions. Taproot is usually choked out by expansion of roots around it or is diverted from its downward growth by unfavorable growing conditions.

44. Roots Mycorrhizae (fungus roots) - the symbiotic relationship of roots with certain fungi Symbiosis – both organisms benefit from the living arrangement Fungi get food & in turn aid roots in absorption of water and minerals Mycorrhizae = fungus root -> a mutualistic association of a root + a mat of fungus in through the tissues or wrapped around outside • fungus obtains organic nutrients from the plant fungus has a long, thin filamentous body which provides a large surface area to absorb more minerals for the plant ->  most plants (~60%) have mycorrhizae Mycorrhizae = fungus root -> a mutualistic association of a root + a mat of fungus in through the tissues or wrapped around outside • fungus obtains organic nutrients from the plant fungus has a long, thin filamentous body which provides a large surface area to absorb more minerals for the plant ->  most plants (~60%) have mycorrhizae

45. 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) Initial investigation showed no obvious cause of death. While mainly cypresses were being affected in this area there were also unhealthy/dying pines. Foliage samples were analyzed and results showed very high levels of chloride.The toxic level for chloride in pines is 0.35%. Some of these samples had levels as high as 5%.Rainfall over several years has been well below average, particularly over winter. This dry period was followed last year (2000) by above average winter rainfall. Initial investigation showed no obvious cause of death. While mainly cypresses were being affected in this area there were also unhealthy/dying pines. Foliage samples were analyzed and results showed very high levels of chloride.The toxic level for chloride in pines is 0.35%. Some of these samples had levels as high as 5%.Rainfall over several years has been well below average, particularly over winter. This dry period was followed last year (2000) by above average winter rainfall.

46. Allelopathy Production and release of chemical substances by one species that inhibit the growth of other species of plants Reduced seed germination and seedling growth Examples: Walnut, red maple, swamp chestnut oak, sweet bay, red cedar

47. Flowers & Fruit Flower is reproductive structure of plant Once pollinated give rise to the fruit or seed Most seeds are protected with an ovary or capsule

48. Tree Physiology 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 Immunolocalisation studies revealed AUX1 appears asymmetrically localized in root protophloem pole cells Photo from Nottingham University in UKImmunolocalisation studies revealed AUX1 appears asymmetrically localized in root protophloem pole cells Photo from Nottingham University in UK

49. Plant Hormones regulate Growth Hormones signal: Cell Division Cell Elongation Flowering Fruit Ripening Leaf Drop Dormancy Root Development

50. Plant Response to Environment Tropisms: Geotropism-gravity response Phototropism-light response Hydrotropism-water response

51. Photosynthesis Converting light into sugar for food Chlorophyll is the green/leaf pigment that absorbs sunlight Chlorophyll is stored in chloroplast cells of leaves (Chloroplasts is where Photosynthesis takes place) ENERGY IS STORED

52. Respiration Energy made from photosynthesis is used (Sugar or carbohydrates /starch) Oxygen is needed Carbon dioxide and water are given off Tree able to survive in these situations? 1. Flooded roots (tree roots cannot respire=death) 2. Defoliated leaves by caterpillars (reserved food=lives) ENERGY IS RELEASED

54. Transpiration Loss of water through stomata (openings) of leaves -similar to perspiration in people 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

55. Tree Physiology Compartmentalization is a system of defense CODIT:Compartmentalization Of Decay In Trees

56. Tree Physiology Shigo’s model is 4 barrier “walls” 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 Wall 1 is the weakest, and Wall 4 is the strongest barrier. At times, the tree cannot resist the spread of aggressive pathogens. It is fairly common for walls 1, 2, and 3 to fail, allowing decay to spread inside the tree, forming a hollow cavity. Wall 4 rarely fails, except where canker-causing fungi restrict its development or kill the cambium. The barrier zone is strong chemically but weak structurally. The process that resists the spread of disease can also lead to shakes and cracks.Wall 1 is the weakest, and Wall 4 is the strongest barrier. At times, the tree cannot resist the spread of aggressive pathogens. It is fairly common for walls 1, 2, and 3 to fail, allowing decay to spread inside the tree, forming a hollow cavity. Wall 4 rarely fails, except where canker-causing fungi restrict its development or kill the cambium. The barrier zone is strong chemically but weak structurally. The process that resists the spread of disease can also lead to shakes and cracks.

57. Tree Physiology Shigo’s model Wall 4 is the next layer of wood to form after injury Strongest of all 4 walls Protects from outward decay Barrier zone

58. Palms Monocots Have no cambium layer Have no growth ring of xylem Have vascular bundles of xylem & phloem Growth inside a monocot cell is different from the growth in a dicot cell.  This is mainly due to the arrangement of the xylem and phloem.  In monocot cells the xylem and phloem are arranged in vascular bundles, scattered throughout the stem.  These are the type of cells which make up all annuals and most biennials because they have no need to increase the size of their stems.  A monocot cell system is unable to produce new layers of a xylem and phloem because they lacks a vascular cambium.  A monocot stem does not increase much in width only in height. Photo is from Smithsonian Marine Station, Ft. PierceGrowth inside a monocot cell is different from the growth in a dicot cell.  This is mainly due to the arrangement of the xylem and phloem.  In monocot cells the xylem and phloem are arranged in vascular bundles, scattered throughout the stem.  These are the type of cells which make up all annuals and most biennials because they have no need to increase the size of their stems.  A monocot cell system is unable to produce new layers of a xylem and phloem because they lacks a vascular cambium.  A monocot stem does not increase much in width only in height. Photo is from Smithsonian Marine Station, Ft. Pierce

59. Helpful Websites for Tree ID ISA Tree List & Exam Study Guide http://www.isa-arbor.com/certification/exams.aspx http://wp.nres.uiuc.edu http://urbanext.uiuc.edu/treeselector http://utgardens.tennessee.edu/ohld220/  http://www.noble.org/webapps/plantimagegallery/PlantList.aspx?PlantTypeID=3&IndexType=CommonName  http://www.hort.uconn.edu/Plants/

60. Illinois Chapter ISA Certification Workshop Series Jennifer Hitchcock jenflwr@gmail.com 847-826-8763