Dendrology Sections 4&5

Seedlings

first year of life

Saplings

small trees after first year, not sexually mature

Mature

capable of reproducing

Senecent

growing old decaying

Imbition

the uptake of a liquid from an area of high potential (substrate) to and area of low potential (the seed)

Germination

process of absorbing water, reactivation of metabolic processes, and initiation of growth

Scarification

mechanical abrasion to seed coats that are hard and impervious to water

Stratification

subjection of seeds to required environment

Excurrent Growth

growth has a dominant central leader with a conical crown (conifers, sweetgum, yellow poplar)

Decurrent Growth

growth has spreading branches (most hardwoods)

Diffused Porosity

slow, even vessel production

Ring Porosity

large vessels in spring, smaller vessels later

Early Wood

rapid tree growth in spring, cells large, low density and thin cells walls

Late Wood

slow growth in summer, cells are small and of high density and thick cells walls

Reaction Wood

abnormal secondary xylem that grows in response to bending with tension and compression types differing in compositions

Tension Wood

reaction wood in hardwoods, formed on the upper side of the leaning stem, lightweight and high in cellulose

Compression Wood

reaction wood in conifers, formed on lower side of leaning stems, heavy and high in lignin

Sapwood

lighter younger wood near the bark, active xylem and storage cells, ray parenchyma for storage and movement of compounds towards heartwood

Heartwood

darker wood towards the center of the tree, old, dead xylem; conducts no water/minerals, often contains substances toxic to decay fungi which leads to darker wood

Inner Bark

consists of layers of secondary phloem, transports sugars in live innermost layers, outermost layers are dead

Outer Bark

consists of three layers that make up the periderm (phellogen, phelloderm, cork “phellem”)

Phellogen

actively dividing, producing cork cells

Phelloderm

inside phellogen but not all trees have it, alive and may rely on photosynthesis, stores starch

Cork (Phellem)

outermost layer, at maturity, cells are dead and contain suberin

Suberin

waxy substance that serves as barrier to water and pathogens

Buds

meristematic tissues that enable primary growth and are protected by simple leaves called cataphylls

Chlorophyll

primary food producing pigment, reflects green

Carotenoids

reflects yellow or orange; usually masked until chlorophyll decline

Tannis

bitter tasting pigment in some species contributes to brown color

Anthocyanins

usually aren’t visible in summer, responsible for pink, red and purple

Fixed or Determinate Shoot Growth

one flush of growth per year, preformed leaves in terminal bud, growth stops when last leaf reaches full size, new terminal bud forms but doesn’t open till following year, examples include: northern trees mostly conifers

Free or Indeterminate Shoot Growth

continual growth as long as conditions are favorable, when conditions suck the outer stem tissue dies and outer most lateral bud acts as terminal bud for next years growth, false terminal buds have scar at the base of the bud, crooked twigs, some example are: birch, willow, elm, tulip poplar

Recurrent Flushing or Semi-Determinate Shoot Growth

can exhibit growth multiple times per season, pausing during stress and resuming later, produce elongation for longer period than fixed growth

Important Genera for Birds

• pinus

• prunus

• quercus

• rubus

• vaccinium

• diospryous

• elaeagnys

• morus

• sambucus

Important General for Small Mammals

• prunus

• quercus

• rubus

• vaccinium

• carya

• fagus

• morus

Important Genera for Large Mammals

• quercus

• vaccinium

• diospryous

Important Genera for Deer

• acer

• euynonymous

Overall Important Genera

• pinus

• prunus

• quercus

• rubus

• vaccinium

Factors Influencing Fruit Value

• plant distribution

• species composition

• season of fruit production

• animal nutritional needs

• annual differences in fruit production

• amount of fruit produced

• size of fruit produced

• viability of fruit produced

• chemicals produced

• outer husks

• use of fruit

Factors Influencing Browse Value

• plant digestability

• plant distribution

• animal nutritional needs

• chemicals produced

• other deterents