This page's content is no longer actively maintained, but the material has been kept on-line for historical purposes.
The page may contain broken links or outdated information, and parts may not function in current web browsers.

Research Results

How does Age of a Forest Affect the Amount of Carbon Storage in a Forest Ecosystem?


Since the Industrial Revolution, there has been a dramatic change in Earth's temperature, but nobody really knew why it was happening. During this period of time, machines were created to replace working animals; machines and other technology replaced hand tools. Before this revolution, people used wood to obtain energy and heat, but Europeans found out that in the soil they could find "energy-rich materials, which were useful to replace wood and go even further giving the necessary materials to drive machines, such as cars, planes, and many others. The energy-rich materials were mostly coal, oil, and gas. These are called fossil fuels". (Sagan; Billions and Billions, P.118)

Fossil fuels are mostly made of fossil remains of organisms, such as ferns, horsetails and mosses, from millions of years ago. "The chemical energy within them is a kind of stored sunlight originally accumulated by ancient plants." (Sagan; Billions and Billions, P.118) How do these plants store the energy?

Plants respire as well as all other animals, but they also have the ability to do a process known as photosynthesis. Photosynthesis is the process by which plants take atmospheric CO2 and water to produce food (glucose) for themselves and release oxygen. This process is related to the cycle that maintains life in Earth, the carbon cycle. The carbon cycle is the removal of CO2 by photosynthesis and its return to the atmosphere by cellular respiration. During photosynthesis the photosynthetic organisms absorb CO2 and convert it into organic compounds by the process of carbon fixation. The photosynthetic organisms break down these organic compounds during cellular respiration, which releases CO2 into the atmosphere. If animals consume plants, they will get some of the carbon compounds, and also will release CO2 into the atmosphere through cellular respiration. Finally, the decomposers break down animal wastes and the remains of dead organisms, which also releases CO2 into the atmosphere. This cycle keeps a balance in the amount of CO2 found in the atmosphere of the Earth, but since the Industrial Revolution CO2 has been increasing due to human activities.

All of these processes occur in a big area called forest. A forest is a dense growth of trees, plants, and underbrush covering a large area. In this place we can find many different environments which are helpful in the storage of CO2, helping the temperature and climate of the Earth. This means that forests are very important to us and especially to the storage of carbon in the trees and the soil.

Scientists have been looking at the amount of CO2 in parts per million (ppm) in the atmosphere above Hawaii, since the 1950's. They chose this place because industrialization and deforestation is slower than in many other places around the world. This helps to see the difference between the amount of CO2 in an area with less industry and an area with more industry, showing the influence of industries in the amount of CO2 found in the atmosphere. The way that scientists measure CO2 is in PPM. They do this by taking a million of particles in air and counting the ones that are CO2, is like taking an area of the air and look at CO2 in that area. The records show an increase in the amount of CO2 of 50 ppm since the 1950's to the 1990's. As we see an increase in CO2 we also see an increase in temperature. How CO2 is related to the temperature of the Earth? Carbon dioxide is one of the gases that produce the Greenhouse Effect.

The Greenhouse Effect (G.E.) is the trap or absorption of heat in the Earth's atmosphere. This is called the Greenhouse Effect because is analogous to a green house, which absorbs UV and X-rays light from the sun. Carbon dioxide and many other gases have this effect on the Earth. This may be why we see an increase in temperature as we see an increase in the amount of CO2 in the atmosphere. These gases come from the burning of fossil fuels, which is contribute to the economy and are part of our lifestyle. Also, fossil fuels support the fuel of industries, transportation vehicles, and energy. The increase in G.E. can have a huge influence in the different changes of climate, producing more droughts, hurricanes, and storms than the normal ones. These are important problems because they affect the economy of the countries, but they are not more important than the rise in temperature that appears to be related to the increase of CO2 that we are emitting into the atmosphere.

One of the main issues that concern the science community is to find ways to reduce the amount of CO2, therefore helping to reduce temperature of the Earth. Because people are burning fossil fuels at such rapid rate, the environment is not having enough time to adapt or maintain the amount of CO2 that is found in the atmosphere.

A research team at NASA Goddard Institute for Space Studies involved in the ICP, including scientists, faculty, and students, are trying to find ways of using the natural environment of a forest to reduce the amount of carbon found in the atmosphere. The ways that they are doing this is comparing the storage of CO2 in many different environments and trying to see which type of environment seems to absorb and/or reduce CO2 from the atmosphere. Overall, the team for the BRF research was divided in sub-groups in order to research the carbon storage of the different environments of this forest. The first group is comparing a burned area with an unburned area to see if a forest release a lot of carbon when is burned. This helps to know the effect of fire in relationship with climate.

The second group is comparing an old forest with a young forest to see if a forest that has not been disturbed for a long time (old forest) will have more carbon storage than one that is in the process of growing. The third group is comparing native trees (Temperate Deciduous Forest), with human planted ones (Coniferous or Spruce Trees) which are not naturally from the area, showing if a plantation can adapt to an environment and absorb more carbon than the natural trees of that environment, or to see if the Coniferous store more carbon than Deciduous trees. Measuring the amount of CO2 in each of the environments gives an advance to answer the research question which was: " Between a young and an old forest, which forest stores more carbon?" The information obtained from this project may be used in the development of new ideas or methods to reduce the release of CO2 into the atmosphere. One example is that knowing that deforestation will keep going on, is necessary to know which trees, (young or old), should be cut down, and will have less impact increasing the amount of CO2 in the atmosphere. Also, with the comparisons of the amount of CO2 store in the different environments, researchers can see which environments work better storing carbon, and could create or expand environments like those and reduce the ones that are not very effective storing carbon.


What is the difference in carbon stored, in trees and soil, between an old and a young forest? One important part of this experiment is the comparison of carbon storage between an old and a young forest. This gives information of which trees, (old or young), stores more carbon, helping to understand which trees should be allow to grow in the different environments of a forest.

In order to obtain this information two-study areas were chose, one with young trees and one with old trees. Once areas were selected, they were measured and plotted off at an area of 42.5 square meters. After the site designation, a Global Positioning System (GPS) was used to obtain the latitude, longitude, and the elevation of the sites. A topographic map was subsequently used to identify the specific site locations. Using a compass, the group described the orientation and sketched a map for each site including its topographic surroundings. Also, vertical and landscape surveys were taken. Once all this was done, the data collection started.

In order to obtain a description of the sites and to see other factors that influence the amount of carbon storage in those sites, the field team collected some data daily, and other data every other day. Soil depth measurements were taken at each of the four corners and the center of the sites. The data collected daily included: (1) the measurements of air, floor and soil (7cm deep) of the center of the site with a thermometer, (2) the wind speed and direction with a wind speed meter and a compass, (3) the cloud type and cover was estimated, (4) the sun intensity in each of the four corners using a voltmeter and a photovoltaic cell (a little solar panel).

The data collected every other day included: (1) the soil pH using a soil corer to take topsoil, and soil at 15cm and 30cm deep in the center of the site, (2) the soil moisture using the soil corer to get soil at 5cm and 10cm deep. The soil samples obtained were taken to the laboratory; the ones for pH were mixed with distilled water, and then with an indicator paper soil acidity was identified; the ones for soil moisture were taken to the laboratory too, in the lab were weighed, and dried in a 60°-100°C oven. The next day, the samples were weighed again; the results were recorded, and the samples were kept for further study.

To determine the Forest Carbon Storage Data, the group numbered and identified with a tree identification guide, each tree found in both sites. They measured the circumference of the trees, (DBH or Diameter at Breast Height → equations → estimate carbon), with a measuring cloth tape, at an elevation of 1.3 meters off the ground. Using the tree canopy guide, they identified each tree by their canopy, (S = suppressed trees that are slow in growth or mostly young, C = co-dominant trees thata are in the middle between suppressed and dominant trees, D = dominatn trees that tower over all the other trees of the canopy). After identifying the tree canopy, they used a tree-measuring device to look at the top of each tree. The height of a tree was estimated by the angle at which the person looks at the tree and the distance that the person is from the tree.

The final step was the measurement of carbon in soil. With the soil corer, the group took a sample of the forest floor and one at 10cm deep. These samples were taken to the laboratory in Black Rock Forest. In the lab, the samples were dry up in the oven at 100°C, then weighted, and placed back into the oven at a higher temperature of 600°C to burn off all the organic matter. After this, the soil was reweighted. The difference between the initial and final weight gave the mass of organic matter. The mass of the organic matter was divided by the original weight; the result was multiplied by 100, giving the percentage of organic matter in the soil. The carbon content was half pf the organic matter.


After two weeks of investigation in the Black Rock Forest, to compare a young with and old forest, we came up with these results:

Figure 1

Figure 1

Figure 1 above shows the diversity of tree species and the amount of trees in the two environments. Diversity of trees is important because trees store carbon at different rates, some faster than others, and a higher diversity could increase the storage of carbon in an ecosystem. As shown, there are more trees in the young forest, especially maples, which allows more diversity in this forest. Also there is no Red Oak in the old forest, which is one of the tallest trees in the young forest, (shown in Figure 1), therefore stores more carbon. The amounts of Yellow Birch and Witch Hazel is small in both forests, meaning that most of these trees are suppressed and had died, because they don't received as much sun light as the Oaks or Maples, which are mostly dominants.

Figure 2

Figure 2

A tree that has a big or wide diameter is an old tree, while a tree with a small diameter is a young tree. An older tree has more carbon storage because as the carbon is being store, the trunk grows. Figure 2 above shows the diameter, in inches, of the trees by their species. The diameter was used to calculate the amount of carbon stored. As shown, there are more maples, but most or them are young or with a small diameter. The amount of Witch Hazel and Yellow Birch is very small. The Oaks seems to have bigger diameters, meaning that they are older, especially the Chestnut Oak, which are the ones with wider trunks. This means that the Chestnut Oak have more carbon store.

Figure 3

Figure 3

Figure 3 above show the height of the different species of trees. This height was also used to calculate the amount of carbon storage on trees. The trees located in the old forest are taller than the ones in the young forest. Each species of trees is taller in the old forest, except the Red Oak because there is none in the old forest. This occurred because the trees in the old forest had been around longer, so all the trees that are left are mostly dominants, while there is just a few suppressed. In the young forest, trees are still trying to compete to be dominants, otherwise the suppressed will eventually die.

Figure 4

Figure 4

Figure 4 above shows the carbon storage in the different environments which, eventually, will help to obtain an answer for the main question. The main question was to investigate which environment, young or old, store more carbon? Here we see the comparison in the amount of carbon storage between an old and a young forest. Figure 4 shows that the young forest has more carbon store, and this could be because there are more trees in this forest, also there is more diversity and the trees growing. With these results we can conclude that if we cut old trees, there will be less release of CO2 to the atmosphere that if we cut down young trees.


It is important to find ways to store carbon, and one place where it can be store is a forest. This is why the main goal of the Black Rock Forest Carbon Initiative group was to investigate the amount of carbon stored in natural and impacted ecosystems of the Black Rock Forest. Carbon is one of the main factors for life on Earth, but in the last century, the amount of carbon had increase dramatically, affecting climate which influences the life of all organisms on Earth. This is happening because we are burning fossils fuels as such rapid rate that the photosynthetic organisms don't have enough time or space to store all this carbon. With a control in the amount of atmospheric carbon, we can maintain the cycle of this gas under a constant rate or in homeostasis; therefore, the climate will not change dramatically, and organisms will not have to make dramatic adaptations in order to survive.

The main goal of the field team was to compare the amount of carbon storage in an old and a young. The young forest or site 1 is 35 years old, with different species of trees, such as Red Maples, Chestnut and Red Oaks, Witch Hazels, and Yellow Birches, which belongs to different canopies, (dominant, co-dominant, suppressed), and/or had different heights. The old forest or site 2 is 150 years old, with the same species from site 1 but the Red Oak, and most of them are dominants and co-dominants, with just a few suppressed. The most common trees on site 1 were Red Maples, and in site 2 were Chestnut Oaks.

There are many factors that affect these results, and we have to investigate them. Some of these factors are the measurements of the amount of carbon storage in the soil, which could not be done. It is necessary to convince more researchers to conduct field work on larger plots, and repeat this experiment many times to obtain a more certain conclusion. Also it is important to research other environments found in this forest, especially wetlands. This information will provide a better understanding of how much carbon is stored in forests. Such studies can be used by policy makers to make informed decisions about the environment and development, in particular climate change policies.

Further Questions

  1. If there is any difference in carbon storage of an ecosystem through the years, why this difference occurs?
  2. What predictions can be done about the carbon storage of an ecosystem?
  3. How much carbon is store in the forest soil?
  4. How carbon store in the forest floor differs in amount from the carbon store in trees?
  5. Which is the best ecosystem to store carbon?


  1. Carl Sagan, 1997; Billions and Billions, P.118
  2. Warren M. Washington, Where's the Heat?, Natural History 3/90, P.70