Tree Biology Flashcards
What is Arboriculture
Understanding trees and how they grow
Arborist use knowledge of growth and development to diagnose health issues, assess genetic potential, and prescribe treatments that ethical and appropriate. Arborist must understand to tree biology to prescribe a treatment or a treatment plan
What is Tree Biology
Study of structure and function and the relationship between them
What are Angiosperms
Plants that produce flowers and that bear their seeds in fruits. ( apple, jacaranda, gold medallion trees )
What are gymnosperms
Plants that have seeds but no flowers. ( conifers, ginkgo, cycads)
Why do we need to know how a tree grows?
One must know how things should be to know when they are broken.
Helps to diagnose and prescribe treatments.
Understanding that genetics are influenced by external stimulus helps to assess
their potential in a given environment.
What is a tree?
Trees are large woody plants with
a single or multiple trunks
Cells and Tissues of Trees
In trees, division occurs in specialized zones called Meristems
After division, cells undergo
Differentiation that change their structure and permits
them to assume a variety of functions and specific roles within the tree.
Cells with similar structure and function are arranged into tissues, bark and wood.
5 Organs of Trees
Leaves, stems, roots, flowers, and cones, or fruit
What is Primary Growth
the increase of height and length
Root tips
Shoot tips
Occurs in small areas of root and shoot tips called the Apical Meristems
What is secondary growth
growth that increases the thickness of stems, branches, and roots.
Where are Apical Meristems found
Apical meristems are
found inside the buds where overlapping
scales or modified leaves of buds protect
both the meristematic region and
developing shoot.
What are Lateral Meristems and what 2 components do they consist of
Trees have two lateral meristems which produce the secondary growth.
Vascular Cambium- is the first. This thin sheath layer of dividing cells are located under the bark. It produces the cells that will become the vascular system of the tree. The two tissues it produces are Xylem ( wood ) to the inside and Phloem to the outside.
Cork cambium- it is the second. It produces the outer tissues (periderm) and, ultimately, the bark.
In Palms, they do not produce secondary growth.
What is Cellulose
the structure component of the primary cell wall which plays a roll in providing the architecture of different types of cells. It provides tensile strength to cell walls.
What is Lignin
This is another component that is more rigid of the plant cells that form in the cell walls of wood. Both of these components packed tightly together create a very stiff cell wall unlike any other plant. They increase the stiffness, rigidity and strength of the tree. Lignin is found in all plant cells.
What is Xylem
It is the wood of the tree.
Composed of dead and living cells.
It has 4 functions: conduct water and
Mineral elements, support the weight
Of the tree, storage and reserves, and
Defense against the spread of disease
And decay.
What are Parenchyma cells
Can be found in the tree stems, roots, and leaves. They are defined as tissue that is composed of living cells with very thin cell walls. They have various functions such as healing plant wounds (resins and gums ), growth, photosynthesis, starch ( food ) storage, and structure support
Whats the difference between Gymnosperms and Angiosperms
Parenchyma cells are more abundant in Angiosperm trees. Vessels ( in Hardwoods ) and Tracheids ( in Conifers ).Pine trees lack Vessels entirely and also lack Xylem Fibers.
What are Vessels
the primary water and nutrient conducting elements in Angiosperms such as maples and oaks. The Xylem Vessels can be thought of as stacks of dead, open-ended, hollow cells that form long tubes for conducting water, like straws from the roots to the leaves. Consider it as the trees plumbing pipes. Vessels are more efficient in water conduction than Tracheids are.
What are Tracheids
are water transporting, conducting and mechanical supporting cells in the Xylem of Gymnosperms (pines).
The wood of (softwood) of Gymnosperms such as Pines and other conifers are mainly composed of Tracheids. Ferns are also mostly made up of Tracheid cells.
What is Diffuse Porous
small Vessel element cells ( also called pores ) that are evenly spread throughout each growth ring. Diffuse porous trees form Vessels of roughly the same radial diameter throughout the growing season. Diffuse porous trees are usually found in the tropical areas. Maples, Birches, plane,and poplar are examples of Diffuse porous trees
What is Ring Porous
species have large vessel cells in the beginning of the season ( early wood ) that make the growth rings very apparent in Ring porous trees. Larger Vessels are laid down in spring and they get smaller towards the end of the season
Ash, Elms, Catalpa, Honeylocust, and Oak trees are example of trees with Ring Porous trees
what are Growth Rings
is the increments of wood added during a single growth period. These rings are a results of the cambium seasonal Xylem production. This growth is usually one year, in which case the growth ring may be called an “annual ring”. In tropical regions, growth may not be recognizable or not annual
Growth rings are distinct if conducting cells produced early in the growth period are larger ( spring , or early, wood ) than those produced later ( summer, or late, wood ).
What is Earlywood
(springwood) is wood formed in the spring and the beginning of the growing season. Usually made up of larger thinned walled cells.
What is Latewood
(summerwood) is wood formed in the late summer or fall. Usually ,made up of smaller, thicker walled cells.
The latewood generally is denser and darker than earlywood
What is Sapwood
the tree’s pipeline for water moving up to the leaves. Sapwood is new wood that is formed.
As newer rings of sapwood is being developed, inner cells die and are pushed to the inside and turn into heartwood.
three main functions: Support, conduction and storage.
lighter would fragile and darker would denser
What is Heartwood
nonconducting Xylem that contains no living cells and is sometimes darker in color than Sapwood. The heartwood contributes to mechanical support of the tree, can resist invasion by microorganisms, and is important for Carbon storage
What is Phloem?
he innermost layer of the bark, next to the wood (Xylem ). Phloem Is the vascular tissue in trees that conducts food ( sugars, carbohydrates ) made in leaves by Photosynthesis downward to other parts of the tree for consumption and storage
can also move substances upward if needed from sources to sinks through Sieve Tubes. Phloem lives for only a short time, then dies and turns to cork to become part of the protective outer bark. The old phloem basically gets crushed.
What are Sieve tubes
components of the Phloem in trees that are located just outside the Cambial Zone. They function as the vessel that transports organic food ( sugars ) and other materials from one location to another.
In Gymnosperms (or pines and conifers), the Phloem lacks both the sieve tube and corresponding cells\
FOUND IN ANGIOSPERMS
What are Companion Cells
specialized Parenchyma Cells in the Pholem tissues of the Anigosperms
Carry out metabolic functions for Sieve Tubes elements and provide them with energy.
Function to load sugars ( or photosynthates ) into cavity of sieve tube members.
NOT FOUND IN GYMNOSPERMS
What are Rays
are the radial transport cell system. Rays are made up of parenchyma cells that grow radially, like spokes on a bicycle wheel, and extend across the growth increments of xylem and into the phloem
transport carbohydrates and other compounds into and out of sapwood, store carbohydrates as starch, and assist in restricting decay.
It is also a component of C.O.D.I.T
What is axial transport
The movement of water in the xylem and photosynthate in the phloem (longitudinal transport)
What is radial transport
he movement of water or nutrients within the tree between cells of different ages, primarily through ray cells. (laterally)
What is the Bark
Bark is the protective outside layer of the tree. It is the outer covering of branches, stems, and in some cases. roots.
It is composed of protective tissue that moderates the temperature inside the stem, offer defense against injury, and reduce water loss. Outer bark is composed of corky tissue.
What are Lenticels
small porous openings in the bark that permit gas exchange of oxygen and carbon dioxide. Lenticels play a major part in Transpiration where some water is loss. Birch and cherry trees have very prominent lenticels. Lenticels are formed of loosely packed dead cells
Roles of Stems and Twigs
Branches support twigs, and the trunk supports the entire crown. Both leaf and flower buds are typically found at the end of existing shoots or at leaf base.
What are Adventitious Buds
growth or bud that appears in an unusual place. It can form on a root, leaf, or occasionally on shoots or branches. They develop when stimulated or triggered by the loss of apical buds and the hormones they produce
brazilian pepper or poplar trees are examples of this
(forming from new latent buds)
What are Epicormic Shoots
are latent buds suppressed within growing tissues, originating with the first years shoot and remaining suppressed beneath the bark until growth is triggered by increase light or tree injury. Usually from roots or base of trunk.
Brazilian pepper and olive is a good example.
(arising from existing dormant buds)
What are Water Sprouts
also a result of stress or over stimulation, will develop on trunks and branches of tree.
Epicormic Conspiracy
misconception that sprouts rob energy from the tree and that they should be “cleaned out” from the trunk and branches
Contrary to this popular beleaf, arborist have proven that these sprouts serve several valuable functions.
Stress response- drought, storms, pest, can be backup to produce food.
Regeneration- injury, from heavy pruning can help produce food.
What are nodes
the points on a stem where
the buds, leaves, and branching
twigs originate. May include flowers or fruit.
What is the internodes
space between nodes
Scars are visible on new twigs and are useful in
Measuring annual twig elongation on some species.
What are branches
grow from the trunk of the tree and help the transport of water, sugar, and nutrients to leaves and canopy ( crown ) of the tree. They also help support the leaves that make up the canopy ( crown )
What is the Branch Collar
swollen area of the trunk tissue that forms around the base of the branch. It is interacting layers of cells of the branch and trunk, and is the part that will heal the wound left by pruning. The Branch collar seals off the wounds, minimizing disease and decay.
Branch bark ridge
raised area of the bark in the branch crotch that marks where the branch wood and trunk wood meet. Cutting into the Branch bark ridge will destroy the tree’s natural defense mechanisms that promote wound compartmentalization and callus formation.
What is included bark
type of branch defect that develops when two or more stems (co-dominant stems ) grow closely together in a v-shape.
Acacia, Mesquite, and Ornamental Pears trees are trees that commonly have included bark.
What do leaves do
uniquely adapted to carry out the roles of Photosynthesis and Transpiration
facilitates the exchange of gases and absorption of light
what is the cuticle
outer leaf is covered by a waxy layer
minimizes drying out of leaf
what is the stomata
small openings mostly on the underside of leaf surface, control the loss or water vapor and the exchange of gases
stomata will usually open in sunlight, but will open during the night because of high temps and low humidity
what are guard cells
regulate the opening and closing of the stomata in response to environmental stimuli such as light, temperature, and humidity.
Two essential components for photosynthesis
carbon and water.
What are photosynthates
the building blocks for many other compounds required by the plant
primarily stored by the tree in the form of starch for later energy requirements when not put to immediate use.
Proteins, starch, fat, cellulose, lignin, growth, regulators, amino acids made by this
What is Respiration
process by which the carbohydrates are converted in a controlled manner into energy
photosynthesis should exceed respiration
at night tree must rely on stored carbs
What is Transpiration
the process by which moisture ( water ) is carried through the tree from roots to stomata on the underside of leaves, which also cools the leaves in the process
What is a source
Leaves are the source of photosynthates
What are sinks
Sinks are plant parts that need more energy or utilize more energy than they produce. Almost all plant parts are sinks at some time, including young leaves
Do evergreens lose their foliage?
will hold on to their leaves for sometimes more than a year.
Do deciduous trees lose their foliage
are trees that shed their leaves in response to periodic environmental changes, such as day length, temperature, and/or rainfall because of cell changes and growth regulators triggering leaf drop.
fall foliage is breakdown of chlorophyll
anthocyanins (reds) Carotenoids (yellow)
What is the Abscission zone
formed at the base of the petiole in autumn which enables leaf drop, protect the region of the stem from which the leaf has fallen from infections
What are the 4 functions of Roots
Anchorage ( Balboa park Ficus )
Storage ( B. Pepper Roots )
Absorption ( Euc Roots )
Conduction
Larger root structure is similar to trunk and branching structure
What are Absorbing roots
small, fibrous, parts at the ends and along the main, large woody roots that increase the surface area of absorption. They are responsible for absorption of water and minerals
What do roots need and where do they grow
Roots need three things, water, air, and good soil to allow for good root penetration.
Most absorbing roots are found in the upper 12 inch of soil where there is good moisture and drainage, organic materials and good air.
What are lateral roots
take up some water and nutrients and grow horizontally near the surface of the soil and help to provide anchorage. Carbohydrates (Reserved energy) are stored here too.
What are Sinker Roots
are roots which grow vertically downward off the lateral roots, providing improved anchorage and access to available water deeper in the soil profile.
What is Taproot
the large, central, downward growing root from which other roots sprout laterally because of unfavorable growing conditions. These become lateral roots. Few mature trees have taproots. ( mature citrus trees )
Once tap root hits around 8% of oxygen in the soil, sapling will send out lateral roots.
What is Root crown
roots spread out rather quickly in diameter in the “ zone of rapid taper “, to long, spreading, branching roots.
Roots without restrictions can spread out 2-3 times the trees canopy. Roots will travel in areas of least restrictions and most favorable conditions.
What is Osmosis
the movement of water through a membrane from a region of high potential ( water concentration ) to a region of low water potential
If the water potential is lower in the soil than root cells, water will actually move out of the roots into the soil
example is when salt concentrations are high in the soil such as from deicing or excessive fertilizer application.
Control and Growth Development Importance
result of the interaction between its genetic potential and the surrounding environmental conditions
Magnolia
Monterey pine
Ficus
What are Plant Growth Regulators
Chemical messengers that act in small quantities to regulate plant growth and development in many different ways
What are some Plant Growth Substances and what do they do
auxins, gibberellins, cytokinins, ethylene, and abscisic acids
work together to control such functions as cell division, cell elongation, flowering, fruit ripening, leaf drop, dormancy, and root development.
What are Auxins
plant growth hormones linked to several developmental processes. Although auxins are produced primarily in shoot tips, they are known to be important in root development.
auxins is produced in the shoot tips may partially explain why heavy crown pruning to compensate for root loss during transplant has not proved to be effective
Removing the shoot tips decreases auxin flow, which has the effect of inhibiting root growth and also triggers lateral shoot development.
What are cytokinins
produced in the roots, are instrumental in shoot initiation and growth
What is Tropism
directional growth of a plant in response to external stimulus such as light or gravity. Example of tropism is the upward orientation of stem growth or downward direction of root growth
What are Decurrent trees
trees with weak apical dominance resulting in a rounded or spreading crown. Common trees are oaks, elms, ficus.
Decurrent trees can grow with a excurrent habit if growing suppressed under the other trees or there its not allowed to growth in an open space.
What excurrent trees
trees with stronger apical dominance resulting in a central leader and lateral growth suppressed. Common trees are most conifers, alders, poplars.
Many trees maintain a strong excurrent for throughout most of their lives but develop a rounded top as they age.Young trees mostly all start as excurrent trees.
can become decurrent
