FORESTRY K1 '25 Flashcards (copied from Erin's <3)

inner to outer tree layers

xylem, vascular cambium, active phloem, inactive phloem, phelloderm, cork cambium, phellem, periderm (aka outer bark)

secondary cortex parts

inactive/secondary phloem and phelloderm

Root plate

area covered by the 3-10 largest roots, located closest to the trunk and provide primary structural support for the tree

3 types of roots, from largest to smallest

structural roots (aka root plate), transport roots, and absorbing roots

what factors influence the growth pattern of roots?

water availability, gravity, oxygen availability, temperature extremes

terminal bud hormone

uses auxins to inhibit axillary buds

Preventitious lateral buds

formed during growing season, grows inside tree without creating new shoots until signaled by lateral bud or growth regulator

Adventitious lateral buds

form spontaneously at the time it's needed (ie wound, attack), shoot forms during the same growth season

twig year 1

shoot

twig year 2 and 3

branchlet

twig year 4+

branch

Describe how branches are connected to the main trunk using 3 vocab words (not counting trunk flange)

The branch bark ridge is the top of the connection. Located at the area of confluence between the branch and trunk, where xylem tissues criss cross together. On bottom of branch is the branch collar, where the trunk grows a little bit around the smaller branch

Semi evergreen trees

keep needles for a single growing season but never multiple years

does transpiration occur at night?

yes, pull from higher water still strong enough when stomata closed

Factors affecting transpiration rate

humidity, temperature, water availability

how do roots absorb water

transpiration pulls water up, creating an area of lower water pressure inside the root, so water flows in from outside

define mass flow

the movement of dissolved nutrients from the soil into roots. They are pulled through the soil along with water as transpiration pulls the water into the roots

what is translocation

the active transport of sugars from their areas of production (leaves) to where they are needed (rest of tree)

auxin

Control cell expansion & elongation, such as growing roots and shoots or tropism by telling cells where to bend. Created in shoot tips, flow to root tips

Cytokinins

Control cell division in shoots. Produced at root tips and transported to shoots via xylem to tell them if there are enough nutrients to grow or not

Giberellins

short, intermediate msgs, signal flowering and branch development

abiscic acid (ABA)

byproduct of photosynthesis that builds up and eventually inhibits auxins, causing leaf drop

CODIT

Compartmentalization of Decay in Trees

Wall 1

stops vertical spreading of decay by plugging top and bottom of xylem

Wall 2

stops inner spreading by creating a chemical defense in the annual rings inwards of the infection

Wall 3

stops transverse spreading by blocking plasmodesmata in ray cells surrounding the wound

reaction zones

wall 123, occur within first year of the wound

Wall 4

strongest wall b/c both physical and chemical. The cambium on outside of tree creates thick cells called the barrier zone, which prevents the decay from spreading into new growth

how long do root hairs last

2-3 weeks

List the parts of a root cross section from inwards out

Vascular tissue, pericycle, endodermis, cortex, exodermis, epidermis

Root cortex 3 functions

• transports water from epidermis to vascular tissue

• stores energy as starch

• separates endodermis from exodermis

epidermis function

partially dead cells, provides physical barrier for protection, insulation, gas control, basic nutrient absorption

Pericycle function

internal support for root, forms new lateral roots

exodermis function

living cells, continuously growing to replace dead epidermis cells

endodermis function

is watertight due to suberin coating and thus regulates water and nutrient movement into vascular tissue

sieve cells

helps roots separate nutrients and minerals from the absorbed water

pith made of

parenchyma with rings of xylem and phloem

inner bark

made of cells that transport sap and nutrients

how is heartwood different from sapwood

xylem cells are modified to be harder and more rot-resistant

xylem combines to form _, phloem combines to form

vessel elements, sieve tubes

xylem can transport water ____ while phloem can transport sugar solutions ____

only up tree, up and down tree

parenchyma cell function

soft and spongy cells that surround and nourish phloem and xylem cells. Make up most of tree’s volume

Fiber bundles

mostly made of cellulose, long slender cells usually found in bundles

optimal temp for photosynthesis

65-85F

how does photosynthesis change with light intensity

positive correlation until a certain point where it plateaus, different for every spcies

what % of water absorbed by roots used by transpiration

90%

If photosynthesis rate much higher than respiration rate

photosynthesis slows down or stops bc photosynthates cant be broken down

hardwood traits

angiosperm, have vascular tubes throughout wood which increase workability and density, more expensive bc grows slowly. Used for furniture and flooring

softwood traits

gymnosperm, usually completely changes its needles every 2 years. Wood is less dense due to tracheids instead of pores transporting nutrients. Used for cheap construction materials (plywood, particleboard) and pulpwood

when did the first gymnosperms emerge? Angiosperms?

319 mya, 150 mya

angiosperm vs gymnosperm species number

300-500k, 1k