1. 3.Seed plants have wood producing tissue well developed for water conduction and support. This enables plants to grow tall and out-compete neighbors Vegetative Conifer adaptations for drier environments

2. Conducting tissue Water from roots Xylem tissue Trachieds Parenchyma Sugars from leaves Phloem tissue The secondary phloem in Pinus has sieve and albuminous cells and parenchyma with dark contents. Conducting tissue is composed of xylem and phloem tissues

3. In conifers it consists of: tracheids that conduct water upwards, are long in the vertical direction, and have bordered pits parenchyma, thin walled cells ray cells running horizontally through the xylem and are composed mainly of parenchyma and some tracheids Secondary xylem is a complex tissue

4. Cross secction of a young pine stem

5. Cambium and secondary xylem of a conifer Cambium Ray initials Late wood Early wood RaysTracheids with bordered pits Parenchyma Esau 1965 Cambium and secondary xylem of a conifer Direction of growth

6. http://www.uri.edu/artsci/bio/plant_anatomy/43.html Tangential longitudinal section Pits Tracheids and rays, pine

7. Craig Aumann Cavitation and recovery from cavitation in Douglas-fir wood

8. Radial longitudinal section Tracheids with bordered pits, pine

9. Bordered pits as seen in face view (left) and in side view (right). http://www.uri.edu/artsci/bio/plant_anatomy/images.html The torus at the center of the bordered pit moves and seals the pit when a tracheid aspirates Circular bordered pits of pine tracheids

10. Transverse section Ray Epithelial cell Tracheid Xylary resin duct in Pinus

11. Terminate cartoon 1.Plants accumulate matter and make growth 2.Plant growth is an organized process following rules of anatomy and morphology 3.Plants actively maintain their heat and water balance 4.Plants have a life cycle with reproduction and dispersal 5.Evolution is a constant process How can we characterize conifers? Enduring, specialists at slow sustained growth sometimes with fast young stages Many anatomical and morphological adaptations, including shade tolearnce Stomatal control, and possibly avoidance of high radiation loads by foliage. Endurance is still the prime characteristic Not dependent upon a water film – but the characteristic is wind pollination (wasteful?). Seeds There are many specialists and there are local races (known as provenances in forestry)

12. How the ecology of conifers determines an environmental issue

13. Forest fires in natural ecosystems Yellowstone National Park 1988

14. Many conifer species are adapted to withstand fire and/or regenerate following fire Forest fire can occur naturally Examples? Conifer species in the western USA form largely ‘dry’ land forests

15. Forest Fires in the United States Note the frequency and distribution of lightning caused fires

16. An estimated 16 million thunderstorms occur each year on earth, causing some 100 lightning strokes to the ground per second. Between 50 and 80 percent of forest fires in western North America are lightning caused. There are some 4,871 lightning fires per year on federally-owned land in the US. Lightning never strikes twice? http://www.chaseday.com/lightning.htm

17. Why are forest fires a problem? Fire suppression has resulted in the accumulation of high fuel loads

18. Satellite photograph of the Biscuit Fir, S.W. Oregon August 14, 2002

19. The Biscuit Fire started as a result of a series of lightning strikes on July 13, 2002 on the Siskiyou National Forest It cost an estimated $135m to suppress at the date of containment. The fire grew to 499,570 acres over two months On July 11, 2002, a Red Flag Warning was issued for dry lightning across southwestern Oregon beginning July 12. There were a number of lightening strikes from the same lightening cell and a number of fires were started on hill tops with no road access. Some fire staff had already been sent to New Mexico and Colorado fires. There was difficult, i.e., not safe access, and initially the fire had low regional priority.

20. Forest fires frequently start when lightening strikes on hill tops and may produce multiple small fires. There are at least 4 in this picture This type of location can be difficult for firefighters to reach Icicle fire, Washington State, 2001

21. Fire in ponderosa pine forest Prior to 1900 low elevation ponderosa pine forests burned every 5 to 30 years Most fires burned only the forest floor reducing fuel and killing small trees This produced open stands of large trees with grassy understories, some shrubs and occasional thickets of young trees.

22. After fire in Ponderosa pine The “natural” size of a fire is very small (less than an acre) when the forest has a variable structure

23. Effects of fire exclusion in Ponderosa pine Fire exclusion has produced a dense understory of young Douglas fir Deep woody debris and duff give hotter longer lasting fires and poor germination Since the advent of fire fighting some forests have missed 8 to 10 fire rotations

24. These photos were taken at Lick Creek in the Bitterroot Valley of Montana over an eighty-year period. Notice how the old growth ponderosa pine stand is replaced by dense Douglas-fir after fire suppression begins in the 1920s. The consequences of fire protection in Ponderosa pine Exit PowerPoint

25. Controlled burning Ground fire What conditions of fuel load, moisture content, temperature and wind produce a fire that burns the excess undergrowth and small trees without burning the dominant trees? East side of the Cascades set in late fall

26. The effect of a controlled burn Before After The effect of a controlled burn Has sufficient material been removed to prevent a major conflagration? in a Pinus ponderosa forest Crater Lake, lower elevation forest burnt in early spring

27. Is there such a thing as a “natural” forest? wherever there has been an effective fire suppression policy is it reasonable to conclude that forests there are not natural? If we define “natural” as not influenced by humans then