NREM 301 Forest Ecology & Soils

1. NREM 301 Forest Ecology & Soils Day 25 November 11, 2008 Nutrient Cycling Field Quiz Today – Be Prepared for Wet

2. Field Quiz Slope Position & Shape Summit (linear) Shoulder (convex) Lester Soil Depth Hayden Backslope (linear) Ice Transported Storden Glacial Till (concave) Footslope Residual Bedrock (linear) Toeslope Terril Coland Colluvial Spillville Alluvial Soils – Parent Material – Topography in Central Iowa

3. Soil & FF horizons, texture, structure L – litter (Oi) F – fermentation (Oe) H – humus (Oa) Kinds of FF’s Mor – Oi (L) Oe (F) Oa (H) Conifer Acid Low C/N Deciduous Basic Mull – Oi (L) Oe (F)? Moder – Oi (L) Oe (F) Oa (H)?

4. Riparian Zone Run – fast smooth flow Island Riffle – shallow, turbulent flow Bend – deep pool Thalweg Habitat Units (page 13-14)

5. River Continuum Concept Heterotrophic/Allochthonous Autotrophic/Autochthonous

6. Group Activity - please use this picture to define and provide examples of each of the terms. Lake ecosystem – the biotic & abiotic factors that interact to create the functioning lake system. Vertical Stratification – various canopies in forest Terms Ecology Ecosystem Community Population Ecotone Vertical & Horizontal Stratification Landscape Ecosystem Fish/invertebrates = animal community Aquatic plants – plant community Floating mat of plants – ecotone gradation between aquatic and forest. All individuals of sunfish = the sunfish population Horizontal Stratification lake, floating plant mat, forest All individuals of duck weed = duckweed population Landscape Ecosystem = northern lake/bog ecosystem

7. Differences between plant types

8. Decurrent Weak Apical Control Excurrent Strong Apical Control Many Years 1 3 years Bud Activity & Tree Shape Many Years 1 3 Years P 5 - Handout

9. What wall produced the callous? Radial Wall Rays Tangential Wall Xylem Cell Walls Radial Wall 3 Tangential Wall 4 2 Outside Wall Callus/Cambium 3

10. Yearly Shoot Growth Patterns Determinate growth– terminal bud stays active with strong control Indeterminate growth– no true terminal bud – weak control or may become a floral bud or abort Result of Indeterminate Determinate Indeterminate P 5 - Handout

11. Special Soil Fungi Mycorrhizal Fungi Ectomycorrhizae Mycorrhizae= symbiosis between fungi and root. Fungi receives carbon from plant, plant gets a 10-100X increase in absorbing root surface area. Ectomycorrhizae Basidiomycetes & Ascomycetes * spores wind & water dispersed * 2,100 species of fungi in NA * most conifers, willow, aspen, oak, hickory Endomycorrhizae (VA) Phycomycetes – spores below ground * most widespread, associate with * most plant families including crops * most deciduous trees VA Mycorrhizae (P 10 – Handout)

12. Fruit on what kind of shoots? Short Shoot Long Shoot Short Shoot

13. Bud Growth Patterns Fixed Fixed Growth – one annual flush Free Growth – continuous growth Recurrent Growth (Southern Pines) Free Growth Many Riparian Species P 4 - Handout

14. What is the name for this kind of branch & what kind of bud gives rise to it? Epicormic Branch Adventitious bud

15. How do forest stands respond to disturbance? Stand Development Model Disturbance where original species still present on site. Disturbance where all species have been removed. What kind of species is A?

16. Shifting Mosaic Steady State Model Forbs/Shrubs/Seedlings Gap Succession Older Trees Die Create Gaps – Mixed Species Whole Area Mix Of Different Aged Gaps – Uneven-aged Mixed Species Even-aged Single Species

17. Tolerance Inhibition Facilitation Succession Pathways Site changes: more sunlight, some compaction Site changes: loss of OM structure but soil still fertile Site changes: new material, no bio- logical legacies Any species can seed in if seed can get there light seeded grasses & forbs Any species can seed in if seed can get there Only “pioneer” species can get established All can germinate & start to grow If well established & if fire occurred then could keep woody plants out Next seral stage depends on rate of modification of site by pioneers Mainly shade intolerant will capture site at the beginning Length of grass stage depends on fire Rate of change depends on longevity of species

18. Group Activity Diagram the general nutrient cycle for an ecosystem • Show: • Inputs (how do nutrients get • into an ecosystem) • b) Outputs (how are nutrients • lost from the ecosystem) • c) Internal Cycling (how do • nutrients move around in the • ecosystem Think of nutrients cycling in an ecosystem box

19. Biochemical General Nutrient Cycle Geochemical Biogeochemical Page 525 Textbook

20. Ability of fresh OM to be incorporated into the soil helps dictate rate of cycling Oi (L) Oe (F) Oa (H) Mineral soil

21. Bogs 1. Northern or high elevation climates 2. Water source – precip – bowl with not other in or outputs 3. Anaerobic water 4. Low pH < 5 5. Slows decomposition 6. Sphagnum moss Histisol Organic Soil • Fens • 1. Similar locations • 2. Water source is • groundwater or stream – moving into & out of fen • Higher pH • More nutrients • More plant diversity

22. Group Activity Two Concave Depression Sites Both within about 10 miles of each other – one is at about 6,000 ft the other at 9,000 ft elevation What reasons cause the difference you see? Fen pH very acid Salt Flat pH very basic Low precipitation, high ET Higher precipitation, lower ET, more Plant growth – conifers dominate

23. Fall is here and the leaves are falling off of the trees Group Activity These leaves play an important role in maintaining the organic matter in the soil. How do you think they become part of the OM? Please use this figure to expand your answer

24. Group Activity A) What % of the aspen leaves is water? B) What % of the aspen leaves are C, H, O and ash? Lignins & phenolic compounds Cellulose Sugars, starches & simple proteins Hemicellulose Fats, waxes, etc. Crude proteins C) Rank the compounds from fastest decomposition to slowest.

25. Composition of typical green plant material Sugars, starches & simple proteins Crude proteins Hemicellulose Cellulose Fats, waxes, etc. Lignins & phenolic compounds Rapid decomposition Slow decomposition

26. Soil Meso & Microfauna • Over 1000 species in a single m2 of forest soil • Many of the world’s terrestrial insect species are soil dwellers for at least some stage of their life-cycle • A single gram of soil may contain millions of individuals and several thousand species of bacteria • A typical, healthy soil might contain: • several species of vertebrate animals – moles, shrews, etc. • several species of earthworms, • 20-30 species of mites, • 50-100 species of insects, • tens of species of nematodes, • hundreds of species of fungi • thousands of species of bacteria and actinomycetes.

27. Soil – a very complex ecosystem – 1,000’s of organisms that are critical to global cycles. The most densely packed ecosystem on the planet.

28. Macrofauna - > 2 mm – termites, ants, earthworms, beetles, etc. – can dig through soil & create structures for their movement and habitat (burrows, galleries, nests, etc.) Mesofauna – 0.2-2mm – collembolas, acarids – live in air-filled pores Microfauna - <0.2mm – protozoa, nematodes, rotifers – live in water-filled pores

29. Group Activity A) What is meant by the term detrital food web? B) How is this food web similar, different from the traditional terrestrial food web? C) What are the three major steps of decomposition?

30. Soil (Detrital) Food Web Decomposition • 1. OM is oxidized to water & CO2 • 2. Heat energy released • 3. Nutrients released • (mineralized) • 4. Resistant compounds • produced by organisms

31. C/N Dry Plant OM 42% = C 1-2% = N 1. Microbes need 8 C for 1N to build cells 2. Need 16 C for Rs 3. Need C/N = 24/1 4. If OM > 24:1 microbes take N from NO3 in soil C/N = 30:1 C/N = 120:1 5. So lack of N can slow decomposition C/N = 300:1