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
