Midterm Topics to Review Genetics Regeneration & Seed Production Tree Structure & Growth shape, stem (bark & wood), roots, leaves Bioclimatology Solar radiation

Genetics Influences on plant development Genotype Environment The exact genetic makeup of an individual Environment Climate, parent health, soil fertility, etc. Phenotype Influence of BOTH genotype and environment

Genetics Plasticity of phenotype Variations in genotype Niche

Regeneration

Regeneration

Regeneration

Regeneration – Cone Crop Periodicity

Anatomy Tree form Shoots Stems Roots Leaves Primary growth Primary and secondary growth Roots Leaves

Anatomy – Tree Form Crown shape Competition & Crown Shape Excurrent, Decurrent Competition & Crown Shape Succession, survival, light availability Environmental Conditions – Temperate Forests Environmental conditions In Montana Daylength Drought Temperature Cold Daylength Environmental Conditions – Tropical Forests Leaf senescence, leaf/root imbalance

Anatomy – Tree Growth

Anatomy - Shoots Growth Determined by temperatures, water stress Buds may be resting or dormant Free Growth Fixed Growth Fixed & Free Growth Multiple Flushing Lammas growth

Anatomy - Stems The ability to form (and add) consecutive layers of structural tissues (secondary growth) to the primary stem distinguishes woody species from all other plants. Secondary growth Strengthens the stem Increases transport of food & water between shoots and roots

Anatomy - Stems

Anatomy – Stems - Phloem Phloem Contains Sieve elements Connected by sieve plates to form sieve tubes Active loading & unloading of solutes Companion cells Keep sieve elements viable & store solutes Phloem parenchyma cells Storage & lateral transport of solutes & water Phloem fibers strength

Anatomy – Stems - Xylem Contains Tracheids Vessels Xylem parenchyma Only part of xylem which is alive Xylem fibers Strength

Anatomy – Stems Cavitation Transverse Xylem Cells Parenchyma cells Ray tracheids Earlywood to latewood transition Growth rings

Anatomy – Roots Anchor the tree (whole root system) Store sugars (larger roots) Generation of vegetative shoots (e.g., aspen) Production of some growth hormones Prevent soil erosion Absorption of water & minerals from soil (fine roots) Regulate water loss(?)

Anatomy - Roots Root Types Root Distribution Tap root Fibrous root Adventitious root Root Distribution Horizontal Vertical

Anatomy – Roots - Morphology

Anatomy – Roots - Morphology

Anatomy - Roots Suberized Coarse Roots (permanent) Outer tissue is dead bark HOLD THE TREE UP!!! Unsuberized Fine Roots < 1 mm diameter, white Live 1-3 months Only 1-5% of root biomass, BUT 90% of root surface area DO THE WORK!!!

Anatomy - Roots Root cap Casparian Strip Zone of mitosis Zone of elongation Zone of maturation Casparian Strip Water travel into roots, and then into xylem Root growth and seasonal turnover Root hairs

Anatomy - Roots Rhizosphere Mycorrhizae - fungi Ectomycorrhizae Endomycorrhizae Nitrogen Fixation – bacteria Root nodules Root grafting Benefits Disadvantages “The Living Stump”

Anatomy – Root:Shoot Growth

Anatomy - Leaves Why are leaves green? Stomatal dynamics Why do they change color? Stomatal dynamics What are stomata? What purpose do they serve? What is osmotic potential? How do stomata open/close? (e.g., guard cell dynamics Sun vs. shade leaves

Anatomy - Leaves

Anatomy – Leaves - Angiosperm

Anatomy – Leaves - Gymnosperm

Bioclimatology

Bioclimatology Climate Weather Micro-climate

Bioclimatology - Radiation Insolation Solar declination Seasons Daylength

Bioclimatology - Radiation Electro-magnetic spectrum Shortwave radiation Longwave radiation Energy emission (Stefan-Bolzmann Law) Radiation intensity (Wien’s Law)

Bioclimatology - Radiation Conduction Convection Examples: wood stove, gecko

Bioclimatology - Radiation

Bioclimatology - Radiation Net radiation for a tree Rn = incoming – outgoing  is albedo, which is the reflectivity of a surface

Bioclimatology - Radiation

Bioclimatology - Radiation Surface Energy Balance Rn – G = H + E Bowen Ratio  = H / E

Midterm 10 definitions, 3 points each = 30 points 7 short answer questions, 10 points each = 70 points Sample questions Can a shade-intolerant seedling grow in a stand with a high leaf area index? Explain . What is cavitation? Why is it dangerous? How have trees adapted to reduce/prevent cavitation? Explain the morphology (structure) of tree stem growth that produces the tree rings that we see.