Dendrology Lecture

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Dendrology Lecture
2012-10-14 14:37:44
Dendrology Trees ID

Dendrology Lecture Rutgers University
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  1. What is a tree?
    a woody plant that at maturity is 13 ft. or more in height, with a single trunk at least 3 inches in diameter at breast height (4.5 ft. ), un-branched for at least several feet above the ground, and having a more or less definite crown.
  2. Define Dendrology.
    The Study of trees
  3. By definition, how does a shrub differ from a tree?
    A shrub is a smaller and usually exhibit several erect, spreading, or prostrate stems with a general bushy appearance
  4. How many trees are north of Mexico? How many are considered important as forest trees?
    • 270
    • 200
  5. What is a forest cover type? Give examples.
    • forest stands or cover types consisting of a plant community made up of trees and other woody vegetation, growing more or less closely together.
    • Global
    • United States 
    • Eastern US
  6. What is classification?
    • Ordering of items into groups having common characteristics, and into a hierarchy of successively more inclusive groups
    • Involves two processes: grouping and ranking
  7. Plant classification is a system of hierachical categories.  List this system starting with the largest, most inclusive category down to the smallest, most specific category.
    Division (or Phylum)






  8. What is a phylogeny?
    A taxon at any level should represent one evolutionary line evolved from a common ancestor
  9. In scientific nomenclature, the complete description or name of a tree or plant species consists of three parts.  Name them.
    • 1. a generic name
    • 2. a specific epithet
    • 3. the full or abbreviated name of the person, or persons, who originally published the name and description, or made a later change
  10. Why would nomenclature change? Two reasons.  
    • Two valid reasons for change:
    •  1. nomenclatural (to bring the name into
    • compliance with the rules of nomenclature)
    •  2. taxonomic (evidence reflects the need for a
    • change in classification)
  11. Name three tree characters that can be used to identify a tree.
    • Tree ID takes into account the whole tree in its natural setting; geographic area, habitat, form, bark, twig,
    • leaves, taste or aroma, flowers and fruits or cones
  12. Natural variation can make tree ID challenging.  Name the two types of variation discussed in lecture and define them.
    • Intrinsic – originating within the
    • individual or species;
    • extrinsic – originating from outside; or
    • coming from another species.
  13. Species are not always homogeneous.  Infact, two trees of the same species can be different.  True or false?
  14. Give examples of intrinsic variation.  
    • phenotypic plasticity: environmentally induced variation
    • developmental plasticity: changes that are under stronger
    • genetic control (change from a juvenile leaf form to a mature form)
    • abnormal(mutational): ultimate source of all genetic
    • variation, most are minor
    • chromosomal: changes in chromosome number in
    • trees may or may not be correlated with morphological differences
    • ecotypic: an ecotype or ecological race is a  distinct morphological or physiological form or population resulting form selection by a distinct ecological condition; it has adapted genetically to factors of its local habitat
    • clinal: a character gradient correlated
    • with a geographical or ecological gradient
    • reproductive
    • speciational: basically, ecotypes or
    • populations become genetically isolated and continue to diverge genetically;
    • primary mode of species formation
  15. Types of Intristic Variation Reproduction
    • “outcrossing” – xenogamy: crossing between individual
    • plants;
    • “inbreeding” – autogamy: selfing within a single, bisexual flower; and geitonogamy: crossing between flowers of one
    • plant. Leads to less variation within a population, more differences among
    • populations of a species
    • “Apomixis”: a specialized mechanism that is a
    • substitution of an asexual process for the normal sexual reproduction.
    •      -vegetative apomixes – root sprouts, quaking aspen; and
    •      -agamospermy - the asexual formation of a seed
    • in certain trees like hawthorn or serviceberry.
  16. In terms of physiography, define 'aspect' and briefly state why it can be important in dendrology.
  17. Define 'tolerance' as used in dendrology, and briefly state why it is an important concept for dendrolgy. 
  18. Cheif characteristics of trees usually influence the selection of their common names.  Name two examples of characteristics that influence common names.  
  19. Physical morphology is considered the primary basis for classification of seed plants.  True or False?
  20. What are the tree parts of the leaf?
    Stipule, blade, petiole
  21. Describe one way to distinguish a compound leaf from a simple leaf. 
  22. Define a twig, and name tree reasons why twigs are important for tree ID
  23. What are the three general parts of the lamina that exhibit distinct, discernable characteristics for IDing trees?
  24. Define vegetative morphology and breifly state why it's important for dendrology.  
    Vegetative morphology characteristics include physical charachteristics we can see such as leaves, twigs, etc... It is important because we can see them year round unlike hte reproductive features whcih can only be seen at certain times of the year. 
  25. Define tree habit, excurrent, and decurrent.  Give one example of each. 
  26. What is range and why is it important in dendrology? What is a range map and why is it useful in dendrology?
    • Range is the boundaries where certain tree species are found.  It is importnat to dendrology because it allows us to more accurately determine tree species.  
    • A range map shoews us where a tree species is likely to grow and survive.  It is important because it includes gaps and chan how us where the species is most likely to exist and survive. 
  27. The surface of a leaf can exhibit characters useful for ID.  Name two: 
    Veination, texture
  28. What is an obligate wetland species?  What is a facultative species? upland species?
  29. Tree bark can vary not only within a species but by the age of tree, tree vigor, location and even on different parts of an individual tree.  As a result bark is not considered a particularly useful or primary character for ID.  True or False. 
  30. Name two types of buds commonoly found on the twigs of trees. 
    Axillary and terminal
  31. Deciduous? example. 
    • Drops leaves in fall
    • Red maple
  32. Evergreen? example. 
    • Keeps leaves generally all year, sheffing them once every other year or longer
    • Pine
  33. Marcescent? Example. 
    Drops leaves in spring ( keeps them through winter) - Drop in spring because they are pushed off by new buds.
  34. What is New Jersey's state tree?
    Northern Red Oak
  35. What bird is Darwin famous for studying?
  36. Where did Darwin Study these birds?
    Galapagos Islands
  37. Who said, "Ontogeny recapitulates phylogeny?"
  38. What is the definition of evolution?
    Evolution is change over time
  39. What information does a phyogenetic tree represent?
  40. What is a monophyletic group?
    A common ancestor and all of it's decendents.
  41. Are the dicots a monophyletic group?
  42. What is convergance?
    When two species evolve similar traits
  43. Give an example of convergance.  
    The cacti in the American deserts and the cacti in African deserts. 
  44. What is the key evolutionary innovation that gave rise to angiosperms?
  45. Today's trees all originated from the same single ancestor.  True or False. 
  46. Humans are more closely related to fish than sharks.  True or false. 
  47. Name three plant families with trees. 
    Sapindaceae, Fagaceae, Roseaceae
  48. Life has tree domains, there are no longer five kingdoms.  True or false.
  49. Name a family that contains many toxic and allergenic plants. 
  50. Name a poisonous/allergenic plant. 
    Toxicodendron radicans (posion ivy)
  51. Are trees monophyletic? Explain. 
  52. What is the most exconomically imporant group of gymnosperms?
  53. Phylogeny can be defined as evolutionary relatedness.  True or false.
  54. In an evolutionary tree, a clase is a branch or group of branches. True or false.