© 2022 National Earth Science Teachers Association. All Rights Reserved.

Volume XXXIX, Issue 2 Page 17

Abstract

Reforestation efforts are often cited as one of the 15 most important and effective 

strategies that can be implemented to reduce atmospheric CO2 (Hawken, 2017). The 

project detailed here, is a small-scale, proof-of-concept initiative for a much larger 

and future reforestation campaign in Northern Arizona. This project allowed 

for broad student involvement in what will ultimately be a multi-year effort for 

sequestering CO2. In addition, this project serves as a first step in a potential larger 

Carbon Offset initiative that would be sponsored and championed by all three of the 

State Universities of Arizona (ASU, UofA, and NAU). As part of this NOAA Climate 

Stewards funded project, two-dozen graduate students from the NAU Climate 

Science and Solutions (CSS) graduate program successfully completed a small-scale 

(2-acre) Ponderosa Pine reforestation initiative in the Fall of 2020. These students 

planted ~200 Ponderosa Pine saplings on previously burned National Forest land. 

Future graduate students will subsequently monitor survival rates and carbon 

sequestration. It is hoped that the long-term project will ultimately result in over 

1 million total newly planted trees (approximately 10,000 acres) in the next five years.

Introduction

Global climate change is not a single-solution problem to society and has even earned the 

nickname, “the wicked problem” (Murphy et al., 2012). As crucial players in the global CO2

cycle, forests and trees can help offset emissions by naturally increasing carbon sinks. In 

a CRS Report to Congress (Gorte, 2009), tree planting was deemed to have a greater carbon 

sequestration potential than other land use practices, and serves multiple purposes when 

implemented in areas where tree biomass has been lost. Specifically, it is estimated that on 

average, reforestation can result in the sequestration of between 1.1 and 7.7 metric tons of 

CO2 per acre, per year (Table 1; Brown et al., 1996). 

Among the different terrestrial ecosystems, conifer forests are considered major carbon 

reservoirs. Their contribution to climate change mitigation is established in their large 

Carbon Sequestration Through 

Ponderosa Pine Reforestation

John Fegyveresi, PhD, School of Earth and Sustainability, Northern Arizona University
© 2022 National Earth Science Teachers Association. All Rights Reserved.

Page 18 The Earth Scientist

storage capacity and their ability to 

uptake carbon dioxide from the atmosphere through photosynthesis (Laclau, 

2003). As such, one common species of 

tree found in the forests of Northern 

Arizona, is the Ponderosa Pine.

Based on the EPA’s Carbon Footprint 

Calculator (https://www3.epa.gov/

carbon-footprint-calculator/), an 

average American household in 

Flagstaff produces between ~8-12 metric 

tons of CO2 per year. Thus, an acre 

of Ponderosa Pines planted as part of 

a reforestation strategy in Flagstaff 

could nearly offset the carbon output 

of an entire single-family home. The 

projected 10,000 acres of planned new 

growth as part of this greater project, could offset approximately 21% of all carbon emissions 

from Flagstaff county homes. Furthermore, Ponderosa Pine stands at full maturity, could 

sequester up to 175.1 metric tons of CO2 per hectare. In addition to significant biomass loss 

due to the various local and regional wildfires in Coconino County (e.g., the 1996 Horseshoe 

Fire), the already delicate Ponderosa Pine forests near the margins of the Colorado Plateau 

are losing several thousand additional acres per year due of the impacts of climate change 

and average warmer temperatures. This project aimed to address a portion of these losses. 

Data collected by future graduate classes will also be shared with the School of Forestry and 

the National Forest Foundation in order to inform the larger reforestation project, as well as 

evaluate the success, feasibility, and efficiency of the project. 

At the onset of this project, Northern Arizona University 

Graduate students within the CSS program took a required 

class specific to Climate Change Mitigation in the Fall of 

2020 (course: ENV 675). As part of their class project, they 

were broken up in to seven specific teams for the purposes 

of project preparation, field methods and operations, data 

collection, and report synthesis (as detailed in subsequent 

sections below). These teams were: Literature Review, Site 

Summary, Outreach and Fundraising, Aerial Drone Imagery, 

Automatic Meteorological Station, GPS Tagging, and Soil 

Sampling.

Background and Site Summary

The planting site is located within the Horseshoe Fire 

(1996) burn scar (Figure 1), approximately 25 miles NNW 

of Flagstaff, Arizona. It is characterized by high elevation (~8,000 ft), mean annual precipitation of ~20 inches, 

moderate humidity (<50%), and four distinct seasons (with 

wide ranges in diurnal temperatures). 

Table 1. Estimated Sequestration Potential for Selected U.S. Land Use 

Practices. Adapted from Brown et al., 1996

(in metric tons of CO2 per acre per year)

Activity EPS (2005) USDA (2004)

Afforestation (previously 

cropland/pasture)

2.2 - 9.5 2.7 -

Reforestation 1.1 - 7.7

Riparian or conservation 

buffers (non-forest)

0.4 - 1.0 0.5 -

Reduced/conseration tillage 0.6 - 1.1 0.3 -

Grazing management 0.1 - 1.9 1.1 -

Sources: EPA: U.S. Environmental Protection Agency, Office of Atmospheric Program, Greenhouse Ga

Mitigation Potential in U.S. Forestry and Agriculture, EPA 430-R-05-006, Washington, DC, November 2005, 

Table 2-1, https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100GO8M.TXT. USDA: Jan Lewandrow

Mark Peters, and Carol Jones et al., Economics of Sequestring Carbon in the U.S. Agricultural Sector, USDA

Economic Research Service, Technical Bulletin TB-1909, Washington, DC, April 2004, Table 2.2, https://ww

ers.usda.gov/webdocs/publications/47467/17126_tb1909_1_.

Figure 1. Field location map created in QGIS by the author, using open-source 

satellite imagery
© 2022 National Earth Science Teachers Association. All Rights Reserved.

Volume XXXIX, Issue 2 Page 19

The growing season in this area is relatively short, with the final spring freeze often occurring as late as June, and the first fall freeze as early as September. There are two main 

seasons of precipitation in the area, a summer monsoon (rainy) season, and a winter precipitation, or snowfall season (Staudenmaier 

et al., 2014).

Low precipitation conditions in the 

area may become the new normal as 

climate change increases the mean 

annual temperatures of the region, 

and decreases annual precipitation. 

The 4th National Climate Assessment 

indicates that the Southwest U.S. should 

expect intensifying droughts all while 

the population increases in the region, 

and already limited water resources 

continue to diminish (Gonzalez et al., 

2018). Based on projections from the U.S. 

Climate Explorer Toolkit (https://toolkit.

climate.gov/tool/climate-explorer-0), 

the planting site should expect a mean 

daily max temperature increase of nearly 

10°F by the end of the 21st century if as 

a society we continue on the “business 

as usual” pathway (IPCC – SSP5-8.5 

scenario) of emitting greenhouse gases 

around the globe (Figures 2, 3). Based on 

these predicted changes in temperature 

and precipitation for the region, it is 

imperative that we regularly consider the 

suitability of Ponderosa Pine to inhabit 

this historically Ponderosa-dominated 

landscape in future planting initiatives.

Initial Site Data and Observations

Many aerial photographs and videos of the planting site 

were taken during the planting campaign (Figure 4). 

During the on-site tree planting, the ambient temperature, soil moisture, solar radiation, soil pH, and soil 

nutrient level were all measured by various team 

members. In addition, a Meteorological (ONSET) data 

logger weather station were configured to continually 

monitor local conditions at the site.

Aerial Drone Methods and Data

A designated drone team gathered aerial imagery of 

the site in an effort to create high-resolution figures of 

the planting area. Images gathered were made available 

to all other project teams in order to combine and/or 

Figure 2. Historical 1961-1990 mean daily max temperature for Northern Arizona

U.S. Climate Resilience Toolkit. https://toolkit.climate.gov/tool/climate-explorer

Figure 3. Projected 2090 mean daily max temperature for Northern Arizona under the high emissions 

(SSP5-8.5) scenario  U.S. Climate Resilience Toolkit. https://toolkit.climate.gov/tool/climate-explor

Figure 4. Aerial drone imagery of the project planting site on the Horseshoe Fire 

burn scar. Photo credit: John Fegyveres
© 2022 National Earth Science Teachers Association. All Rights Reserved.

Page 20 The Earth Scientist

incorporate them with their gathered data sets (See also Figures 5–7). The obvious advantage of using a drone for the site imagery, was that it was capable of giving a more complete 

picture of the specific site location as compared to traditional ground-based imagery. 

Additionally, larger-scale aerial images give a better sense of scale for the burn scar and 

planting area. 

ONSET Meteorological Station Methods and Data

Introduction

The ONSET Sensor Station team installed and configured an automated meteorological 

sensor station and data logger at the planting site (Figure 8). This team was responsible 

for downloading all collected sensor data from the planting day, as well as data captured 

over a 10-day period following the planting in order to evaluate any possible longerterm trends. The ONSET sensor Station included sensors for detecting rainfall (inches), 

soil moisture content (m3/m3), solar radiation/Insolation (W/m2), temperature (°F), 

and humidity (%). The station was positioned near an existing snag (dead tree) at the 

primary planting area rendezvous point, and was programed to continuously record 

data at 1-minute intervals.

GPS Methods and Data

The GPS Measurement team gathered and documented all location specifics for the 

two-acre planting site through GPS latitude and longitude waypoints (e.g., Table 2). 

These measurements included GPS Coordinates bounding the entire site itself, as well 

Figure 5A. (top) DJI Phantom 4 drone and components used for aerial 

imagery and site surveying. Photo credit: John Fegyveres

Figure 5B. (bottom) Students preparing DJI Phantom drone for flight 

and image capture. Photo credit: John Fegyveres

Figure 6. View from the NW corner of the planting site. 1) Location of drone

deployment; 2) Location of ONSET Weather Station and main rendezvous point; 3) 

Parking area; 4) Partial view of tree cluster #1. Photo credit: John Fegyveres

Figure 7. (a) Examples of three different student teams near the NE corner of the 

planting site; 1) Original location of Drone Team; 2) Soil/Solar Team collecting 

sample; 3) Tree Planting Team. (b) Soil/Solar Team (left) and Tree Planting Team

(right). (c) Tree Planting Team working cluster #1. Photo credit: John Fegyvere

Figure 7. ONSET Meteorological Station 

installed at the planting site. Data logger

and individual sensors are identified

Photo credit: John Fegyveresi
© 2022 National Earth Science Teachers Association. All Rights Reserved.

Volume XXXIX, Issue 2 Page 21

as coordinates for all individual planted trees, any on-site 

instruments installed (i.e., the ONSET station), and any direct 

measurements made (i.e., soil measurements). 

Soil Methods and Data

The Soil Measurements team set out to gather various data relevant to the health and condition of the soil in the planting area. 

In order to get an accurate and in-depth analysis of current soil 

conditions at the planting site, they used four different instruments. These included the Rapitest Soil Test Kit, Rapitest Digital 

3-way, the Atree 3-Way Meter, and standard Toulifly pH strips. 

Four sampling sites were selected to best represent the integrated soil composition and conditions across the planting site. 

Measurements of nitrogen, phosphorus, potassium, and soil pH, 

were carried out using the Rapitest Soil Test Kit (Figure 9).

At each site, the GPS coordinates were recorded before the soil 

analysis, and soil was sampled from a depth of approximately 

six inches.

Ponderosa Pine Growth

Fortunately, Ponderosa Pines are fairly tolerant of varying 

soil conditions, however they still do prefer soils with a pH 

of between 6.0 to 7.0, and growing best in zones with 30 to 

60 cm average annual precipitation on well-drained soils. 

Once established Ponderosa Pines can also survive in hot and 

dry conditions, exhibiting medium drought tolerance (Ganey 

and Vojta, 2011). When compared to other species of pines, 

Ponderosa Pines are able to tolerate less fertile soils, requiring 

lower soil nitrogen and phosphorus in order to survive. In 

addition, though higher potassium levels are not necessary for 

growth and survival, there is some evidence that potassium 

fertilization can lead to decreased mortality in ponderosa pine 

(Garrison-Johnston et al., 2005). The biggest concern for the soil conditions is that the annual 

rainy (“monsoon”) season did not bring adequate rain totals for the year, leaving the soil 

conditions exceptionally dry. And though an established Ponderosa Pine tree can survive in 

such dry conditions, a young sapling needs additional moisture to properly establish. These 

dry conditions may ultimately lead to a higher mortality rate. 

It is reasonable to conclude that our saplings can grow with the available nutrients of 

nitrogen, potassium, and phosphorus and the pH recorded for the planting site. Mean pH 

reading across all sampling sites and methods, was 5.7. This value is just under the ideal 

threshold of 6.0 (slightly more acidic). The nitrogen reading found in each testing location 

also showed that the levels were depleted. Our phosphorus readings varied at each testing 

site from depletion, to adequate, with two readings not clear enough to record an accurate 

interpretation. Though nitrogen levels were depleted and phosphorus readings were not 

consistent, it is still likely that the conditions are sufficient for tree growth. Lastly, two of our 

testing locations found a surplus of potassium while the other two found an adequate level of 

Table 2. GPS Site Locations

Site Identifiers Longitude Latitude

Site Corner 1 35.445203 -111.7613

Site Corner 2 35.446414 -111.7612

Site Corner 3 35.445178 -111.7606

Site Corner 4 35.4464 -111.7606

Instruments Longitude Latitude

ONSET Sensor Station 35.446517 -111.7612

Soil Sample Identifier Longitude Latitude

Sample 1 35.446389 -111.7606

Sample 2 35.445667 -111.7613

Sample 3 35.445639 -111.7609

Sample 4 35.446278 -111.7608

Figure 9. Students in the Soil Sampling team taking soil chemistry and 

pH measurements at the planting site

Photo credit: John Fegyveresi
© 2022 National Earth Science Teachers Association. All Rights Reserved.

Page 22 The Earth Scientist

potassium. Despite the dry conditions, and based on the collected data however, the results 

should indicate a relatively satisfactory survival rate among the saplings (at least 20-30%).

Conclusions

In total, ~200 new Ponderosa Pine saplings were planted and catalogued on a 

previously burned portion of National Forest land, ~26 miles north of Flagstaff 

Arizona, within the Coconino National Forest. At the planting site, several 

measurements were made, and many instruments were used in order to document an ensemble of relevant data. These included drone photography, soil 

moisture and pH measurements, GPS waypoints and coordinates, and various 

meteorological and solar data. As a part of this campaign, a fundraising and 

social outreach effort was also carried out in an effort to raise awareness and 

funding for future project support. In total, over $500 dollars were raised 

through these efforts. In future years, this planting site will be further monitored by CSS graduate students to estimate overall tree survival rates, as well 

as total sequestered carbon. It is hoped that through this experience, and with 

the collaborations and partnerships built through it, that this initial proofof-concept, small-scale planting campaign, will evolve into a much larger and 

continual reforestation and carbon mitigation effort. Following the project, the 

NAU School of Earth and Sustainability and School of Forestry, have teamed up 

to promote a larger tree-planting fundraising campaign on the NAU campus. 

We have established a NAU Foundation charitable fund through the University 

that will allow for open donations to this campaign. Long term, the multi-year 

extended plan for this project is to plant over 1 million trees over the next five 

years (~10,000 acres). 

References

Brown, S., Sathaye, J., Cannell, M. and Kauppi, P.E., 1996. Mitigation of carbon emissions to 

the atmosphere by forest management. The Commonwealth Forestry Review, pp.80-91.

Ganey, J.L. and Vojta, S.C., 2011. Tree mortality in drought-stressed mixed-conifer and 

ponderosa pine forests, Arizona, USA. Forest Ecology and Management, 261(1), pp.162-168.

Garrison-Johnston, M.T., Shaw, T.M., Mika, P.G. and Johnson, L.R., 2005. Management 

of ponderosa pine nutrition through fertilization. Proceedings of the Symposium on 

Ponderosa Pine: Issues, Trends, and Management. Gen. Tech. Rep PSW-GTR-198. Pacific 

Southwest Research Station, Forest Service, US Department of Agriculture, (198), 

pp.123-143.

Gonzalez, P., et al., 2018. Southwest. In Impacts, Risks, and Adaptation in the United States: 

Fourth National Climate Assessment, U.S. Global Change Research Program, Wash., DC, 

USA, pp.1101–1184. https://nca2018.globalchange.gov/

Gorte, R.W., 2009, May. U.S. tree planting for carbon sequestration. Library of Congress, 

Congressional Research Service. https://digital.library.unt.edu/ark:/67531/metadc689115/

Hawken, P., 2017. Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global 

Warming. Penguin Books.

Laclau. P, 2003. Biomass and carbon sequestration of ponderosa pine plantations and 

native cypress forests in northwest Patagonia, Forest Ecology and Management, (180),

Issues 1–3, pp.317-333.

Murphy, Raymond. Sustainability: A Wicked Problem, Sociologica, Italian Journal of 

Sociology Online, 2/2012, doi: 10.2383/38274

Staudenmaier, M. Jr., Preston, R., Sorenson, P., Johndrow, J., 2014. “Climate of Flagstaff, 

Arizona (Revision 7).” NOAA Technical Memorandum NWS WR-273, pp.1-68.

About the Author

John Fegyveresi, Ph.D., is an 

Assistant Professor of Practice in the 

School of Earth and Sustainability at 

Northern Arizona University where he 

teaches content related to the impacts 

of climate change. Additionally, John

is a research glaciologist and climate 

scientist specializing in the analysis 

and interpretation of ice cores and 

polar ice sheets. He is most drawn to

research questions that address how 

the physical and chemical properties of 

ice can be used to model past climates 

in polar regions and quantify ice-sheet 

deformation and strain history. Prior to

this appointment, Dr. Fegyveresi spent

four years as a Research Physical 

Scientist at the US Army Corps of 

Engineers Cold Regions Research and 

Engineering Lab in Hanover, NH. He has

also spent nine field seasons carrying 

out research in Antarctica. John can be

reached at john.fegyveresi@nau.e

Contributions to this article were 

made by the following MS graduate 

students in the NAU Climate science 

program under the supervision of John 

Fegyveresi, PhD:

Anabeth Avila Arenas; Bryce Beck; 

Jamie Blatter; Samuel Blustein; Caitlin 

Brogan; Dylan Chandler; Jenna Decker; 

Katie Dickinson; Jack Dugan; Katherine 

Dunlap; Sebastian Espinosa; Jillian 

Goulet; Stephannie de Souza 

Fernandes; Brianna Lovato; Christopher 

Moreno; Marie Nabors; Xuechen 

Niu; Mitchell Riner; Bennett Rosenow; 

Crystal Routhe; Maya Shimoni; Virgil 

St Aime; Chelsey Trejo; Ryan Tsingine; 

Hailey Weinberg; Isabelle Wilhelm; Alex 

Wilson; Iris Wu; Taylor Wyum