Tree Lab – Grades 4-8
Vocabulary List
photosynthesis: The process by which green plants manufacture simple sugars in the presence of sunlight, carbon
dioxide, water and chlorophyll.
stomata: Microscopic openings in the surface of a leaf that allow gases to pass in and out.
bud scars: Structures and small markings found on twigs that are left when a leaf or bud falls. These structures seal off
the branch and vary in size and shape based on the tree species.
lenticels: Raised pores found on the stem of a woody plant, that allows for gas exchange. Similar in function to the
stomata on the leaf.
scale scars: Ring like structures found on a twig or branch near the terminal bud scar. Distance between scale scars
indicates the year’s growth
simple leaves: A leaf that is not divided into parts. One part attached by one petiole
petiole: A stalk by which a leaf is attached to a stem.
compound leaves: A leaf that is composed of two or more leaflets on a single petiole.
blade: The flat, extended portion of the leaf.
vein: Vascular tissue found in a leaf or tree. Similar to the veins in animals, veins in leaves and tree trunks transport fluid
and minerals throughout the tree that are essential for daily function.
cambium: A thin layer in a plant stem where new growth begins.
xylem: The tissues of a vascular plant that transport nutrient-rich water upwards from the roots throughout the
plant/tree.
phloem: The tissues of a vascular plant that transport dissolved nutrients (food) from the leaves to other parts of the
plant/tree.
outer bark: The tough outer covering of woody stems, or roots that provide protection for the tree. It includes all
tissues outside the vascular cambium.
inner bark: Living cells in the tree trunk, a pipeline through which food(sugar) is passed within the tree.
heartwood: The older, non-living central wood of a tree or woody plant, usually darker and harder than the younger
sapwood and provides support for the tree.
sapwood: The younger layers of new wood. Sapwood is active in the conduction of water and is usually lighter in color
than heartwood.
emerald ash borer: A green (jewel-toned) beetle, originally native to Asia. Emerald Ash Borer larvae feed on the inner
bark within Ash trees inhibiting the flow of nutrients and sugars up to the leaves. The insect is considered invasive to
North America and is believed to have been transported within the wood of packing crates from Asia.
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