1. High = 98

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) weather – meteorological conditions for the next day-month; local, short-term atmospheric conditions
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) genotype – the true genetic makeup of a tree; it is never seen because of the role of the environment in development
g) primordium – group of cells representing the initial stages of development of a plant organ; undifferentiated
h) photosynthetically active radiation (PAR) – that portion of the sun’s (short wave) radiation that can potentially be used in photosynthesis; about 45% of energy from sun; μm
i) secondary growth – addition to diameter of tree by adding consecutive layers of structural tissues to the primary stem; it strengthens the stem and increases water and nutrient transport
j) tracheids – part of the xylem, transport water; narrower than vessels; connected by pits. They do not transport as much water as vessels, but they are not subject to cavitation either.

4. Question 2: What physical evidence exists to demonstrate that global climate change is a reality? List five (5) different types of evidence, and be specific.
Increasing CO2
Increasing global average temperature
Changing precipitation patterns
Decreasing snowfall in MT
Increasing ocean temperatures (increasing SST)
Rising sea levels
Polar ice caps are getting thinner; smaller sea ice areal extent
Shrinking glaciers
Thawing permafrost
Coral reefs are bleaching (expelling algae)
Rivers freeze later and break up earlier
Increased growing season length
Overall increase in terrestrial NPP
Decrease in ocean NPP
Earlier spring snowmelt
Earlier budburst / Earlier onset of growing season / longer growing seasons

5. Radiation – movement of energy through the air
Question 3: What are the three methods of heat (energy) transfer discussed in lecture? Describe how heat is distributed in each method using the example of the wood stove in your answer.
Radiation – movement of energy through the air
without assistance. When you pile on the logs, you will start to feel the thermal energy, even if there is no air movement in the house. As you continue to pile on the logs, the stove will start to glow with a reddish tint, which is the first visible sign of the radiation occurring.
Convection – transfer of heat via air movement; for example, the stove will heat the air above it, and this air will move with air flow throughout the room, warming the house (e.g., thermals).
Conduction – if you touch the stove, the contact will transfer heat from the stove to your hand. In addition, the water in the teapot will heat as the heat is
transferred from the stove to the pot,
and then to the water.

6. are not broken down yet and, therefore, as the chlorophyll breaks
Question 4: Why do leaves change color in autumn? In your answer, include (a) triggers for color change; (b) the physical process of color change; and (c) the reason that trees exhibit such behavior.
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.
Nitrogen, not energy
Chlorophyll, not chloroplasts
It’s a very good thing spelling doesn’t count!

7. Question 5: What physical property of the earth determines seasonality
Question 5: What physical property of the earth determines seasonality? 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.
The earth’s tilt doesn’t change – it’s the position around the sun
In fact, the earth’s tilt changes every 41,000 – one of drivers of long-term “natural” climate change (changing from 21.5 – 24.5 deg; currently decreasing)

8. Mycorrhizae are fungi that form symbiotic
Question 6: What are mycorrhizae? What is symbiosis? What are some advantages and disadvantages of symbiotic relationships such as those between mycorrhizae and trees?
Mycorrhizae are fungi that form symbiotic
relationships with the roots of trees.
This relationship is mutually beneficial: trees get more water and nutrients, while the mycorrhizae get carbon from the tree to live.
Advantage: Mycorrhizae dramatically increase the amount of surface area for nutrient and water uptake, so trees will grow larger and have a more extensive root system than they otherwise would have.
Potential disadvantage: possible transmission of pathogens
Mycorrhizae are fungi, not bacteria.
They do NOT fix nitrogen or carbon.
They serve to increase the surface area for nutrient and water uptake.
Disadvantage is not that one will take advantage of the other

9. Question 7: What is cavitation. Why is it dangerous
Question 7: What is cavitation? Why is it dangerous? How have trees adapted to reduce/prevent cavitation?
Water is under such great tension, it becomes unstable.
As tension increases, dissolved gases within water escape to the vapor phase forming a bubble.
Bubble expands, filling the vessel element.
Perforation plates prevent it from moving to and damaging other vessels.
The bubble breaks the continuity of the water column, stopping water transport.
Adaptations: latewood development during dry season and evolution of tracheids

10. Question 8: What is multiple flushing. Lammas growth
Question 8: What is multiple flushing? Lammas growth? How do they differ? Give examples of trees that might experience them (one for each).
Multiple flushing is the intermittent growth and development of buds and shoots throughout the season. This is common among trees with a long growing season, such as those along the coasts and in the southern US. (e.g., oak, maple)
Lammas growth, on the other hand, is the growth of dormant, fixed buds late in the summer in response to late summer rains. This is not healthy, because the buds do not have time to fully develop and harden before winter comes. This often occurs in young trees, particularly jack pine and Douglas-fir.
Multiple flushing has resting periods, not dormancy