2. Question 1: Definitions
a) leaf vein – contains xylem and phloem; transport of nutrients, water, carbohydrates to & from leaf
b) heartwood – old, non-functioning xylem; primarily used for support; not required for survival
c) climate – long-term (30-year) average weather of an area, includes information about means & extremes
d) fine roots – unsuberized, used for water uptake; 90% of surface area of root system; little biomass; usually live 1-3 months
e) persistent juveniles – seedlings that can persist for long periods of time in the understory; when a gap in the canopy occurs, they can develop quickly into an adult

3. Question 1: Definitions (cont.)
f) inner bark – contains phloem; located between the vascular cambium and the outer bark; location of carbohydrate transport; eventually collapses to become part of the outer bark
g) lammas growth – development of buds in late summer in fixed growth trees; prevents correct hardening and preparation for dormancy; usually occurs in young trees (esp. jack pine)
h) sensible heat flux – energy that can be sensed as heat; measured as temperature
i) primary growth – development of new plant organs such as shoots, new roots, new leaves; development at the apical meristems
j) free growth – concurrent initiation and elongation of new stem cells; development and growth of buds occurs in the same year

4. Large seed size: oak, walnut, pecan, pine, hazelnut, etc.
Question 2: Give 2 examples of trees with large seed size and two examples of trees with small seed size. How does seed size influence seed disperal?
Large seed size: oak, walnut, pecan, pine, hazelnut, etc.
Small seed size: willow, cottonwood, aspen, etc.
Smaller seeds are wind-dispersed and more widely dispersed, increasing chance for survival and propogation. Larger seeds fall close to the parent, ensuring similar climate conditions to that of the parent.

5. Question 3: What are the three methods of heat transfer discussed in lecture? Describe how heat is distributed using one of the two examples from class.
Radiation – movement of energy through the atmosphere (glowing stove; sun)
Convection – movement of air currents, carrying heat with them (fan-blown heat from stove; heat moving from rock into atmosphere)
Conduction – movement of energy through touch (touching the stove; gecko touching the rock)

6. Question 4: Why do leaves change color in the fall
Question 4: Why do leaves change color in the fall? Explain both how and why this occurs.
Chlorophyll (most abundant pigment in leaves) is broken down first as the tree starts to enter dormancy. The nitrogen and other nutrients are drawn into the tree for use the next spring.
The remaining pigments (carotenoids = carotenes, xanthophyll and anthocyanin) are not broken down yet and, therefore, as the chlorophyll breaks down, they become more visible.

7. Question 5: Explain the 2 factors primarily responsible for the Earth’s seasons. How does daylength change from season to season in Missoula as compared with Hawaii? With Alaska? How does changing daylength impact tree development around Missoula?
2 factors:
Tilt of the earth by 23.5
Location of the earth in its orbit around the sun
In our winter, the Northern Hemisphere is facing away from the sun, resulting in shorter days and longer nights.
In our summer, the Northern Hemisphere is facing towards the sun, resulting in longer days and shorter nights.
As you move away from the equator, daylength changes more and more. In Hawaii, daylength changes little (11-13 hours); In Alaska, daylength changes from 0 to 24 hours. In Missoula, which is between the two, daylength changes from 9-15 hours.
Trees have developed a photoperiod trigger to enter, leave dormancy in Missoula in response to changes in daylength.

8. Question 6: Graph and explain the approximate seasonal timing and sequence of leaf, shoot, root, stem, and cone production for a Ponderosa pine tree in Missoula. LABEL YOUR GRAPH!
Roots start developing in early spring for water uptake; slow down during summer, and pick up again in late summer in search for water & for food storage
Leaves but out in early spring for photosynthesis
Shoots grow at about the same time as the leaves, but slow growth earlier
Cones develop during summer months during time of high photosynthesis and low stress
Stems develop during spring for increased PSN and throughout the summer as conditions allow

9. Shortwave radiation is used by plants (PAR)
Question 7: What is the difference between shortwave and longwave radiation? Which do plants use for photosynthesis?
Shortwave radiation is emitted by the sun, high intensity/temperature, ½ is visible
Longwave radation is emitted by earth (and a little by sun), low intensity/temperature, not visible
Shortwave radiation is used by plants (PAR)

10. Question 8: What is osmotic potential
Question 8: What is osmotic potential? How do stomatal guard cells open and close?
Osmotic potential develops when a solute is added to one side of a semi-permeable membrane. This lowers the water potential of that liquid, causing water to flow in to equalize the potential.
Potassium enters the guard cell, creating osmotic potential. Water follows, and guard cells increase in length (not width) in response to turgor pressure. This forces them to open. The opposite occurs to close guard cells.