Science Olympiad
Forestry
Training
This powerpoint is intended to train students how to use a Tree Key to identify unknown trees. Tree Keys are
are permitted for the competition. The terminology found within is also part of the material that is subject to
part of the competition in the form of questions.
Scientific Names V.S. Common Names
Common names are given to many plants and can be used in everyday
conversation. They are easy to pronounce and are usually descriptive
but there are a few issues with only using commons names:
• trying to communicate with someone from a different region
or country can be difficult
• sometimes the same plant has many different common names
• different plants may have the same common name
• some plants are so rare that no common name is given
The Father of Botany
Carl Linnaeus (1707-1778) is was the first to
consistently use a system of binomial
nomenclature which literally means two
names.
– Scientific names of plants consist of a generic
name (Genus) and a specific epithet, in Latin
either underlined or in italics.
TAXONOMIC
CLASSIFICATION
King David
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Came Over For Good Spaghetti
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Delaware has over 60 species of
trees!
• It is hard to know every tree in the forest so
taxonomists have constructed dichotomous
keys to help identify them.
The Key to Knowledge
• A dichotomous key is a tool that allows the user
to determine the identity of items in the natural
world, such as trees, wildflowers, mammals,
reptiles, rocks, and fish.
• Keys consist of a series of choices that lead the
user to the correct name of a given item.
"Dichotomous" means "divided into two parts".
Therefore, dichotomous keys always give two
choices in each step.
Below is an example of a dichotomous key. Always begin your inquiry at Question 1. Always make sure
to ready both statements completely and chose the one that best describes your unknown. Pay close
attention to where the key instructs you to go next until you arrive at your answer. You will notice each
set of “questions” compares different expressions of the same character.
1.
2.
3.
a. wings covered by an exoskeleton……………….go to step 2
b. wings not covered by an exoskeleton………..….go to step 3
a. body has a round shape………………………….ladybug
b. body has an elongated shape…………………….grasshopper
a. wings point out from the side of the body………dragonfly
b. wings point to the posterior of the body………...housefly
Tree Keys
• Keying is a way to identify a plant or tree by
looking at the similarities and differences that exist
among them.
• A tree key would begin with a group of trees that
are split into two groups by comparing different
expressions of the same character (flower color red
or white).
• In most tree keys, the first set of questions will be
if the tree has needles (evergreen) or broad leaves
(deciduous).
Basic Terminology
IT IS VERY IMPORTANT TO LEARN HOW TO IDENTIFY THE FOLLOWING TERMS TO BE
SUCESSFUL IN KEYING OUT THE UNKNOWN TREE. IF YOU ARE UNABLE TO DECIFER
WHETEHR THE TREE LEAF IS OPPOSITE OR ALTERNATE OR SIMPLE OR COMPOUND, YOU
WILL END UP WITH AN INCORRECT ANSWER.
• Opposite: This is referring to the orientation of the leaves and buds
and twigs and branches. Opposite means the leaves, etc. are directly
across from one another on the branch.
• Alternate: the orientation of the leaves, buds, twigs and branches
are staggered along stem
• Simple leaf: is a leaf that is comprised of one leaflet with a petiole
attaching it to the twig. At the base of the petiole will be a bud. An
example would be red maple.
• Compound leaf: is a leaf that is comprised of many leaflets with a
petiole attaching it to the twig. If you trace back the stem of a
leaflet you will NOT find a bud, therefore it cannot be a leaf.
• Petiole: the stem of a leaf that connects it to the twig
• Margin: the edge of the leaf. It can be entire (uncut), lobed,
toothed, etc.
LEAVES
leaves can be
needle-shaped,
scale-shaped,
or broad and
flat
LEAVES
• Broad leaves can be
simple or compound
and are arranged
along the branch in
an opposite,
alternate, or
whorled pattern.
LEAF MORPHOLOGY
• Leaf shape
• Leaf
Margins
• Leaf
venation
Leaf & Flower
Parts
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Flowers
sepals which are usually green and leaf-like
petals with are brightly colored
stamens (the male reproductive structures)
pistals (the female reproductive structures)
Most tree flowers contain both male and
female parts but some trees are only female
or only male
Major types of forests
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Northern Forests – spruces, firs, pines, tamarack, paper birch, quaking aspen
Pacific Coast Forest – western hemlock, redwood, Douglas fir, western red cedar
Western Mountain Forests – ponderosa pine, lodgepole pine, Engleman spruce,
Douglas fir.
Northeastern Deciduous Forests – eastern hemlock, American beech, red oak,
basswood, sugar maple beech, maples
Central Forests – tuliptree, sycamore, shagbark hickory, white oak, Ohio buckeye
Southeastern Forest – Loblolly pine, shortleaf pine, longleaf pine, mockernut hickory,
live oak.
Subtropical Forest – red mangrove, black mangrove, cabbage palmetto
Unforested Areas – desert, grassland, tundra
Tree Ecology
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Growth requirements
Environmental impacts of trees
Interspecies relationships
Role within their ecosystems
Economic impact
Uses for the various parts of a tree
Mode of dispersal of their seeds
Benefits to the Environment
• Photosynthesis uses carbon dioxide, water and sun energy
to produce oxygen and carbohydrates
• Prevent erosion
• Improve Air Quality – absorb harmful pollutants
• Remove CO2, ozone, small particulate matter
• Help with global warming
• Keep us cool
• Trap rainwater
• Help keep water quality high