Managing Forests as Natural Resourcescushman/courses/engs41/Mark Borsuk's versi… · ENGS 41:...

Modeling of Ecosystem Services:Forests in New England

David LutzENGS 41: Sustainability and Natural Resource Management Lecture #3Thursday, April 16th, 2015

Managing Forests as Natural Resources

Forests have been managed historically for ~ 1000 years!even longer if you consider the management strategies of indigenous N/S Americans!

Timber management played a substantial role in: the U.S. Revolution, the development of New England, expansion of the British Empire

Timber harvest of mast pines in colonial Maine

First Continental Flag of the U.S.A

Flag of New England Colonies

The Pine Tree Riot was one of the first acts of colonial rebellion, thought to be a precursor to the Tea Party.

Great Britain had clearly not optimized for their objectives!

Trees are long-lived individual organisms. Harvesting them commits you to make an irreversible decision.

Not until 1849 (In Germany) was optimization of forest resources thought of in a mathematical way. (more on that later...)

Timber is a major industry in New England and the U.S.

Harvesting White Pines Modern-day industrial chipper

$200 billion dollars in forest product sales in the U.S. alone284 million cubic m of industrial roundwood

62 million cubic m of sawn-wood750 million acres of forestland are managed in the US.

How does one measure a forest?

Diameter Height

For timber purposes, think of a forest as a series of cylinders.

If the total volume held within these cylinders represents product, then for a given stand, one needs to know:

1.) The total number of trees in the stand and,2.) The total volume that resides in those trees

Sampling for a Forest Inventory

Figure 2. Example line-plot layout for 10 percent sampling intensity (Table 1). Circles represent plot locations and dashed lines while arrows represent paced distances and the direction of travel. The first line of plots, on the far right, was paced at an azimuth (a clockwise angle from true north) of 160°, the between-line distance at an azimuth of 250° and the second line at an azimuth of 340°.

The Type of Plot Distributing the Plots

Counting all trees would be time-consuming (expensive), plus, would be rather repetitive!

Instead, a series of plots are taken throughout the area which are used as representations of the type/quantity/quality of timber.

Turning Inventory Data into $s

1.) Average # of trees/plot * # of plots = number of trees on all plots

2.) # of trees per acre = aveage # of trees/plot * per-acre exp. factor

3.) Trees per acre = (# of trees on all plots/# plots) * 10Note that the 10 is a function of the size of your plot radius

International 1/4” board foot volume

Form Class 78Merchantable Height in Logs

DBH (in) 1/2 1 1 1/2 2 2 1/2 3 3 1/2 4 4 1/2 512 30 56 74 92 106 120 128 137 14 40 78 105 132 153 174 187 20016 60 106 143 180 210 241 263 28518 70 136 184 233 274 314 344 37420 90 171 234 296 348 401 440 480 511 54222 110 211 290 368 434 500 552 603 647 69124 130 251 346 441 523 605 664 723 782 84026 160 299 414 528 626 725 801 877 949 102128 190 347 482 616 733 850 938 1027 1114 120130 220 403 560 718 854 991 1094 1198 1306 141532 462 644 826 988 1149 1274 1400 1518 163734 521 728 934 1119 1304 1447 1590 1727 186436 589 826 1063 1274 1485 1650 1814 1974 213538 656 921 1186 1428 1670 1854 2038 2224 241040 731 1030 1329 1598 1868 2081 2294 2494 2693

Now, you can use a lookup chart to determine the volume for each species and class of log!

From there, multiply by stumpage price, and you have $$$$

Back to the optimization of harvests...

where f(T) is the total stock of timber at time T (which you now know!)

p is the timber pricer is the discount rate

Faustmann (although some accredit to earlier economists...see website)

created his famous equation:

The optimal time to harvest is when the Δ of forest value equals interest on the value of the forest!

reading on the history of this: http://tinyurl.com/otmmq6r

This requires an understanding of two things:

Current and future timber stocks Current and future timber prices

Forest models have been designed to simulate both of these!

There are many types of forest simulation models

One example: LANDIS

Project changes in timber stocks/harvested timber

This can provide options to assess for reaching objectives.

We can use models to find optimal rotation

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��!�If the Optimization problem is:

And our models project: Future timber volume Future timber price

Then we can use our models to estimate the maximum NPV given a certain rotation period.

Forests aren’t just valuable for timber, though...

What are some other ecosystem services that forests provide?

How do forests store carbon?

Total potential sequestration = ~1.5 Pg per year(U.S. emissions for 2008 were 1.4 Pg)

This stored carbon is valuable for mitigating climate change

Forests cover ~30% of the Earth’s surface (~15 million square miles, or about 4x the total land area of the United States)

They store more than 2x carbon than is held in the atmosphere(861 ± 66 Pg total storage, 363 ± 21 in live aboveground biomass)

Growing Forests to Mitigate Climate Change

In California’s Greenhouse Gas (GHG) Cap-and-Trade Program, covered entities may use a limited number of ARB offset credits to fulfill up to 8% of their compliance obligation.

- California Air Resources Board, October 29th, 2013

Total Allowances for Sale: 13,865,422Total Allowances Sold: 13,865,422Total Spent on Allowances: $169,435,457

- California Air Resources Board, 2013 Auction - August 4th, 2013

Four strategies laid out by Canadell and Raupach:

1.) Increase forested land through reforestation(tree-planting in areas that have been cleared)

2.) Increase the carbon density of pre-existing forests.(forest management and silvicultural practices)

3.) Expand the use of forest products to replace fossil fuel carbon emissions. (i.e. forests for biofuels)

4.) Reduce emissions from deforestation and degradation (i.e. the UN-REDD program)

1.) Increase Forested Land through Reforestation

Nile Reforestation Project Degraded land in Albania part of CDM

Credits are available for afforestation and reforestation projects through the United Nations CDM program(Clean Development Mechanism)

In 2009, only 4 of 1600 CDM projects were A/R!

One of first two US CARB projects in Eastern Maine

2.) Increase Carbon Density of Existing Forests

Forests can be preferentially thinned to maximize the eventual size and growth of trees, thus storing more carbon.

Sometimes this happens unintentionally - i.e. changing harvest cycles, abandonment of timber lands

3.) Expand Use of Forest Products

Still less than 1% of total energy production in the U.S.

Relevant to the Northern Forest of New Hampshire!

(left) Wheelabrator Claremont Biomass Facility (4.5 MW).

(right) Former NH Gov. Lynch at the proposed Berlin biomass plant (in 2012). Online in 2013 - “In Berlin, biopower plant adds up to jobs”.

4.) Reduce the amount of C released from Deforestation

The UN REDD program is a major effort to fund the prevention of deforestation (but has not been agreed upon yet)

Bilateral agreements (Norway and Indonesia/Brazil), the World Bank, and UNDP/UNEPP funding is in place.

Backtrack: this requires an understanding of two things:

Current and future CARBON stocks Current and future CARBON prices

Forest models have been designed to simulate both of these too!

Carbon

Although this is a bit more tricky than timber...

Carbon storage = annual dynamics of forest tree productivity

Forests uptake and allocate carbon in response to many environmental factors -We must consider lots of different aspects of the forest, climate, and edaphic surroundings.

Here’s an example from the Biome-BGC model

This model was designed to understand nutrient cycling specifically in forestsThere are many types of models that can achieve this goal, with various strengths/weaknesses

Much of this work has been to understand terrestrial carbon budgets

Output of a forest model: biomass simulation

How do we measure the value of Carbon?

Market-based

EU has a regulated trading platformPrices are adjusted based on phases

Shadow Prices

The assignment of $ to non-marketed goodsDerived principally through mathematical models

The U.S. government has a Social Cost of Carbon that it uses for estimates However, according to the IPCC it is “very likely that the [SCC] underestimates” the damages

Source: Böringer et al. 2007

DICE simulates interactions between planetary climate and the global economy

e.g. Nordaus, 1993, Nordhaus 1993, Nordhaus and Radetzki, 1994, Nordhaus and Boyer, 2000, Nordhaus 2007.

It has been used to calculate shadow prices for GHG. How?

Integrated Assessment Model: DICE

Integrated Assessment Model: DICE


Greenhouse gasses affect a basic climate model through additional trapped radiation.

These are summarized in a damage function that then influences social welfare (W) in a global economic model.

Welfare Economics to Calculate C Shadow Prices


The shadow price (V) per unit of emissions (E) is measured within the DICE integrated assessment model through:

V(t)=[(ΔW/ΔE(t))/(ΔW/ΔC(t))]

W= social welfare, C is consumption

+1 unit CO2

? Δ welfare

So what if you want to maximize timber and carbon?

Timber and carbon can both be expressed economically

BUT

Maximizing for timber and maximizing carbon are in conflict!!

Harvest times are vastly different depending on the objective:

Where have you seen this before?What does this indicate in terms of forest management?

Forests contain many types of ecosystem services:

• Supporting: “necessary for the production of other ecosystem services”

• Provisioning: “products obtained from ecosystems”

• Regulating: “obtained from the regulation of ecosystem services”

• Cultural: “Non-material benefits [that] people obtain from ecosystems” - M.E.A

This leads to tradeoff decisions for multiple objectives.Many of these ecosystem services are non-currency based - i.e. your reading

There are ways to convert some to economic terms

For instance, forest biogeophysical interactions with the Earth’s climate

Let’s focus on one of these (albedo) and think of it in the context of modeling forests as a natural resource (Lutz and Howarth).

Betts, 2000

Previous Warnings About Carbon-Only Approach

“Ignoring [biophysical effects] could result in millions of dollars invested in some mitigation projects that provide little climate benefit or, worse, are counter-productive.”*

Jackson et al. 2008, Env. R. Lett.

“Our results show that carbon-centric accounting is, in many cases, insufficient for climate mitigation policies.”*

Zhao and Jackson, 2013, Ecol. Mono.

Where is the tradeoff located?

* Emphasis Mine

Albedo decays as a function of stand age,Hence there is a direct tradeoff b/w carbon storage

Bare ground 20 years 50 years

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Let’s Look at Forests where Snow is Frequent

White Mountain National Forest, New Hampshire

And Construct a Model to Evaluate Tradeoffs

Valuing Albedo as an Ecosystem Service: Implications for Forest ManagementIn press, Climatic Change

First things first, how do we value albedo and carbon?

Welfare Economics to Calculate C Shadow Prices


The shadow price (V) per unit of emissions (E) is measured within the DICE integrated assessment model through:

V(t)=[(ΔW/ΔE(t))/(ΔW/ΔC(t))]


+1 unit CO2

? Δ welfare

Welfare Economics to Calculate RF Shadow Prices


+1 unit w/m2

? Δ welfare

Radiative Forcing

We can apply a similar methodology to create a shadow price (V) for albedo radiative forcing (RF):

V(t)=[(ΔW/ΔRF(t))/(ΔW/ΔC(t))]


Using DICE, we can calculate future prices of V(RF)

Now that we have albedo prices...

Let’s calculate radiative forcing from albedo at our sites

Calculating radiative forcing from albedo requires a little bit of atmospheric physics + remote sensing.

RFα = -RTOA fa αs

RF Albedo RF top of atmosphere

2-way transmittance factor

Albedo

Following work by Bright et al. 2012, Cherubini et al. 2012, Bright et al. 2013, Cherubini et al. 2013, Chen and Ohring, 1984

1.) RTOA

RTOA;i ¼Rsc

π1þ 0:033 cos

360di365

� �· cosL cos δ sinω þ πω

180sinL sinδ

� �ð13Þ

δ ¼ 23:45 sin 360284þ di

365

� �

ω ¼ cos−1 − tanL tanδð Þ:

RF top of atmosphere

modified from Ruddiman, 2001


2) fa

2-way transmittance

factor

f a ¼ KTTa:

NASA Surface Meteorology and Solar Energy +

International Satellite Cloud Climatology Project


3) αs

Albedo

IGBP classification stand maps from WMNF

MCD43A, MOD10A

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ClearedHardwoodSpruce Fir

Derive Albedo from MODIS products (MOD10A, MCD43A)

Daily Radiative Forcing for 2 forest types + bare ground(in w/m2)

Albedo and RF match other recorded data in the literature:

(Jin et al. 2002, Betts and Ball 1997, Burakowski et al. in prep, Houspanossian et al. 2013)

RFα = -RTOA fa αs

Incorporate the traditional forest contributions...

Gutrich and Howarth, 2007

VðsÞ ¼ a0 1−ð1−a1Þðs−a2Þ� �

sza20 sba2

(

fsawðsÞ ¼0 b0s=ðsþ b1Þ−b2b0

b0s=ðsþ b1Þ−b2 b0s=ðsþ b1Þ−b2a½0;1�1 b0s=ðsþ b1Þ−b2N1:

8<:

CðtÞ ¼ CliveðtÞ þ CdeadðtÞ þ CsoilðtÞ þX4i¼1

Cprodði; tÞ:

Remember: albedo decays as a function of stand age

Bare ground 20 years 50 years

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Drive exponential decay function

α = a ∗ b t

0

0.0475

0.0950

0.1425

0.1900

0 25 50 75 100

200 year rotation

0

0.0475

0.0950

0.1425

0.1900

0 25 50 75 100

30 year rotation

Monte Carlo Approach with Different Harvest Rotations

+ +

Timber T imber and Carbon T imber , Carbon, A lbedo

Optimal rotation (years) 33 81 51NPV 840 2413 4207




Optimal Rotation (years) 34 248 25NPV 504 1244 5218


Optimal Rotation (years) 45 267 247NPV 418 1926 5483


No Constraint

2 Deg. Constraint

W M N F Hardwood

Northern Hardwood

W M N F Spruce F ir

Spruce F ir

No Constraint

2 Deg. Constraint

No Constraint

2 Deg. Constraint

No Constraint

2 Deg. Constraint

•Including carbon increases optimal rotation age.•Adding albedo to the equation then decreases it.•This is more pronounced in spruce-fir than hardwood forests

Optimal Harvest of Spruce-Fir Shorter with Albedo

WMNF Spruce Fir Timber Timber + Carbon Timber, C, Albedo

Optimal Rotation 34 247 25

NPV ($) 504 1244 2467

Timber and Carbon Timber, Carbon, Albedo

Let’s look at this across many sites in New Hampshire

Mean optimal rotation period = 94 yearsHigh albedo = 59 years, low albedo = 112

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Pri

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$/w

yr)

Years

DICE No Constraint

DICE 2 deg. Constraint

GWP 20

GTP 20

Euskirchen et al. 2013

What Happens When we Use Other Prices?

Depending on the pricing system you use:

Low = 0 year rotation (perpetual harvest)High = 117 year rotation (S-F), 222 (MBB)

The Price of Snow: The Use of Climate Metrics for Forest Albedo ValuationTarget: Environmental Research Letters

DICE No Constraint DICE 2� Constraint GWP 20 GWP 100 GWP 500 GTP 20 GTP 100 GTP 500 Euskirchen et al. 2013

Optimal Rotation (years) 25 27 0 78 116 0 81 117 57

Maximum NPV ($) 2467 4421 13477 1281 1243 14764 1257 1240 1586

Optimal Rotation (years) 54 222 27 80 81 0 81 81 75

Maximum NPV ($) 2813 6417 3669 2431 2414 4143 2423 2413 2547

Spruce-Fir

Maple-Beech-Birch

Timber, carbon, and albedo is just part of the picture

Climate Dynamics

AlbedoForest Carbon/Timber

Economic Valuation

Average albedo (2002-2012)

Optimal Rotation Age

25

NPV ($) 2467

Year with low snowfall (2012)

Optimal Rotation Age

35

NPV ($) 1802

How does variability in snowfall change matters?

Currently our model treats snowfall as static, with a baseline from MODISWhen we elect individual years as a baseline:

Optimal rotations change by 10 years

There is a total difference in NPV of $665/ha

Climate Change will shift snowfall patterns into the future

Hayhoe et al. 2007

We must incorporate projections of future snow!

Top: Days per year of snow-covered conditionsBottom: Difference b/w future and baseline

Timber, carbon, and albedo is just part of the picture

Climate Dynamics

AlbedoForest Carbon/Timber

Land Cover Change

Economic Valuation

Lacking in the forest model:

- Influence on shifting land use throughout the state.- Impact of climate change on forest growth, succession, and migration.

Land C

LANDIS is a landscape-scale forest model that contains elements of fine-scale stand-dynamics

Integrating the FACT model with components of LANDIS will address both climate and land-use for future projections of ecosystem service flows in forests.

Improvements with LANDIS

Climate Change will alter successional trajectories and forest composition

LANDIS has been used to simulate these dynamics

• How do we manage for climate-driven migration of tree species?• How will T,C,A change with different emissions trajectories?• How will species habitats change? What about biodiversity valuation?

Only through incorporating multiple properties of forests will we understand how to manage forested ecosystems in a fashion that provides maximum

environmental and social benefits.

“It is important to consider our influence on all of the [climatic] system components and to work toward a better representation of the full system.”*

Marland et al. 2003, Clim. Pol.

Forests provide many different ecosystem services!

What are some other types of tradeoffs you could imagine occurring while managing forests?

What sorts of questions do you have about this type of modeling and management work?

Thanks to: Richard Howarth, Ryan Bright, Liz Burakowski, Mark Borsuk, Jack Dibb, Jonathan Thompson, the EPSCoR Modeling

Group, SJ Huang, Ross Jones, the Howarth Lab, Queso

Questions?

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