Kelp Forests I. Factors Affecting Kelp Forests A. vanaqua.org Intensity and frequency of winter storms Presence/Absence of urchin predators (sea otters/lobsters) Abundance and behavior of herbivores Winter storms can rip kelps from their holdfasts After severe storms, portions of sea floor may be stripped of kelp 1. 2. 3. • • • • Urchins deprived of preferred foods (mature kelp or drift algae) may increase mobility and eat newly recruited kelps Grazing may prevent kelps from re-growing • Leads to establishment of more resistant coralline algae • Leads to urchin barrens

Kelp forests Kelp forests are found on rocky bottoms and provide habitat for many organisms Gant brown bladder kelp Macrocystis has a strong holdfast and gas-filled floats Macrocystis can grow up to 0.6 meter (2 feet) per day Figure 15-15a

Kelp Forests I. Kelp Forest Ecology B. Sea otters/Lobsters important top-down regulators of community structure • • • • Prey on important grazers like urchins (Pac/Atl) and abalones (Pac) Urchins, abalones, other herbivores graze on attached seaweeds, drift kelp Urchin populations can have a major impact on community composition Fig. 16-11

Revenue Assurance (RA) 5. RA Basic Revenue Guarantee a. APH Yield x Coverage Level x RMA Projected Harvest Price 6. Producers May Choose a “Harvest Price Option” a. RA Harvest Revenue Guarantee b. APH Yield x Coverage Level x RMA Harvest Price 7. Producers Receive An Indemnity If “Crop Value” Is Less Than The Basic Revenue Guarantee (Or, The Harvest Revenue Guarantee) 12

Kelp Forests I. Dominated by brown algae Found in shallow open coastal settings where water temperature usually <20 oC Bottom depth typically <20 m • • • • Light readily available Highly productive, diverse ecosystems • • Productivity related to fast kelp growth rates

Switchgrass Systems Item Bale size Bale wrap Bale density (w.b.) Storage (near field) Delivered product (truck) Bulk Product (Round Bales) 6 ft D x 5 ft L (1.8 m D x 1.5 m L) Net wrap 9 lb/ft3 (144 kg/m3) Outdoor (5% DML) Roll press compacts, bulk density 15 lb/ft3 (240 kg/m3) Common Assumptions: Life span – 10 years Yield (3 – 10 years) – 4.2 dry ton/acre/year (9.4 dry Mg/ha/year) Harvest percent – 80% DM (harvest once after first frost) Harvest yield – 2.9 dry ton/acre/year (6.5 dry Mg/ha/year) Moisture content – 15% (w.b.) Field to storage site – 2 mile (3.2 km) radius Storage site to plant – 30 mile (48.3 km) radius www.biomassCHPethanol.umn.edu Rectangular Bales 8 ft x 4 ft x 3 ft (2.4 m x 1.2 m x 0.9 m) Plastic twine 13 lb/ft3 (208 kg/m3) Indoor (1% DML) Rectangular bales

17. Business: Straight-Line Depreciation Straight-line depreciation for estimating the value of an asset (such as a piece of machinery) as it loses value (“depreciates”) through use. Given the original price of an asset, its useful lifetime, and its scrap value (its value at the end of its useful lifetime), the value of the asset after t years is given by the formula: Pr ice Scrap value Value Pr ice t useful lifetime for 0 t Useful lifetime A. A farmer buys a harvest for $50,000, and estimates its useful life to be 20 years, after which its scrap value will be $6000. Use the formula above to find a formula for the value of V of the harvest after t years, for 0 ≤ t ≤ 20. B. Use your formula to find the value of the harvest after 5 years. C. Graph the function found in part (a) on a graphing calculator on the widow [0,20] by [Hint: use x instead of t.] A.Price = $50,000; useful lifetime = 20 years; scrap value = $6,000. 50,000 6000 V 50,000 t 20 50,000 2,200t 0 t 20 0 t 20 [0,50,000]. B. Substitute t = 5 into the equation. V = 50,000 – 2,200t = 50,000 – 2,200 (5) = 50,000 – 11,000 = $39,000 C. On [0,20] by [0,50,000] OR Use your graphing calculator in parts b and c.

INDUSTRY ATTRACTIVENESS ______________ BUSINESS STRENGTH LOW MEDIUM HIGH Maintain Select for Investment, Grow Invest And Grow MEDIUM Harvest Select for Growth, or Divest Select for investment, Grow LOW Harvest Or Divest Harvest Select for Growth, or Divest HIGH

Reductions in year of harvest The annual payment will be reduced in the year of harvest Example: 15 dry tons of material harvested per acre x $55.00/ bone dry ton = $825.00 per acre Annual payment rental rate = $40.00 per acre If the material is delivered to a biomass conversion facility for conversion to heat, power or bio-based products the reduction percentage is 25% $825.00 x.25 = $206.25 Annual payment would be zero in the year of harvest

RA Example: Price Increase 1. Suppose You Actually Harvest 33 Bushels Per Acre 2. But, The Actual RMA-Determined Harvest Price Increased To $12.00/bushel a. Rather Than The Projected Harvest Price of $11.00/bu. 3. Your “Crop Value” Is a. 33 bu/ac x $12.00/bu = $396/ac 14

RA Example: Price Increase 4. You Do Not Receive An Indemnity From Basic Harvest Revenue Guarantee a. $396/ac > $385/ac 5. Under The Harvest Price Option, You Would Receive An Indemnity a. Harvest Revenue Guarantee Is 50 bu x .70 x $12.00/bu $420/ac b. $396/ac < $420/ac c. $24/ac Indemnity 15