The Cemetery as an Ecological Landscape: Carbon Sequestration and Green Interment Alternatives Kyla Palubinskas, Physical and Earth Sciences Department Abstract Cemeteries are spaces for interring the dead. While contemporary interment practices utilize methods which deplete scarce resources and contribute to environmental degradation, cemeteries themselves perform vital ecological services: habitat preservation, species conservation, and carbon sequestration. In this study we calculate the amount of carbon sequestered in two cemeteries: a managed tree stand in Mount Auburn Cemetery in Cambridge, Massachusetts and an unmanaged tree stand in Rural Cemetery in Worcester, Massachusetts. The sequestration rates from both cemeteries are compared to the overall sequestration rate of Harvard Forest—an unmanaged and previously studied wooded area—to show the potential of cemeteries to remove carbon from the atmosphere. These results highlight the role that cemeteries can play in providing ecological benefits to the wider communities that surround them, making a case for comprehensive conservation and cemetery management strategies associated with green burial practices. Introduction Cemeteries are spaces for interring and memorializing the dead. Cemeteries are also spaces that perform ecological services. Open space within cemeteries acts as a natural habitat for various species of local, sometimes endangered, flora and fauna. In urban areas cemeteries act as parks, providing relief from the bustling streets and highly polluted areas of industrial development. In addition to providing open space and natural habitats for various forms of wildlife, the tree stands located in cemeteries have the ability to sequester considerable amounts of carbon. Currently atmospheric carbon is estimated to be increasing by approximately 2.6 billion metric tons annually (Nowak, 2001). Trees, through their growth process, act as a sink for atmospheric carbon. Therefore, cemeteries which host tree stands are naturally able to reduce atmospheric carbon levels. Despite the environmental benefits cemeteries offer, certain current interment practices degrade the land and deplete natural resources. In this time of climatic uncertainty it is crucial that we begin to view cemeteries as ecological reserves and use them as such. Toxic Burial: Our Final Insult to the Earth Contemporary interment practices utilize environmentally harmful methods. Coffins, vaults, and embalming (except under rare circumstances) are not required by law in any state, yet all are commonly used. In the United States, death-care has become a $15 billion industry—and a wasteful and toxic one at that. Each year we bury:  Enough embalming fluid (now made up of formaldehyde, a known carcinogen according to the World Heath Organization) to fill eight Olympic-size pools  More steel (in coffins alone) than was used to build the Golden Gate Bridge  Enough reinforced concrete to construct a two-lane highway from New York to Detroit (Sehee, 2007)  Approximately 30 million trees, including some tropical species, which are manufactured into coffins (Woodsen, 1998). Though these “traditional” burial practices have been utilized for roughly a century, it would be beneficial to return to earlier, more sustainable, methods of interment. One potential way to go about this is through the propagation of what are commonly called “green burials”. Dying to be Green: An Environmentally Friendly Method of Interment Green burials emphasize the use of biodegradable materials made from renewables, instead of the exotic woods and metals associated with “traditional” coffins. Green burials allow for plots to be recycled. Complete decomposition takes a year, as opposed to the decades it takes for a casketed corpse to decompose. Green burials eliminate the use of hazardous chemicals necessary for embalming, helping to avoid potential soil and groundwater contamination. Additionally, green burials commonly use trees as grave markers. By doing so, these types of burials naturally promote the growth of forests in cemeteries. Carbon Sequestration Forests are a significant part of the global carbon cycle. Through the process of photosynthesis, plants use the energy they receive from sunlight to convert nutrients and atmospheric CO 2 into carbohydrates. As more photosynthesis occurs, more carbon is sequestered, reducing carbon in the atmosphere and storing it above and below ground. Since cemeteries often contain tree stands, they have the ability to both sequester carbon and affect the rate and quantity of emissions of CO 2 from urban areas. Methods Field Methods This research was conducted at Mount Auburn Cemetery, a managed forest, in Cambridge MA, and Rural Cemetery, an unmanaged forest in Worcester, MA. At Mount Auburn, a pre-existing dataset containing measurements from 1996 was also used. At each site, diameter tape was used to measure tree diameter at breast height (DBH). At Mount Auburn, trees in sections 10, 33, and 41 were measured, while at Rural Cemetery, all trees inside the cemetery perimeter were measured. DBH measurements were coded according to the species-specific codes of Jenkins, et al (2004) and entered into a spreadsheet. DBH was converted to aboveground biomass (total dry weight of portion of tree above ground) using species-specific allometric equations (Jenkins et al., 2004). Aboveground biomass was converted to carbon by taking the sum of biomass and dividing by 2 (Fahey et al., 2005). Entire Cemetery Section 10 Section 33Section 41 Sections 10, 33, and Carbon Storage 44.8 MgC/ha49.6 MgC/ha49.7 MgC/ha32.9 MgC/ha44.9 MgC/ha 2012 Carbon Storage 66.7 MgC/ha71.9 MgC/ha73.5 MgC/ha53.7 MgC/ha67.1 MgC/ha Annual Above- ground Sequestration 1.4 MgC/hayr 1.5 MgC/hayr1.3 MgC/hayr1.4 MgC/hayr Results Table 3: Carbon Storage, Mount Auburn Cemetery These results show a significant increase in the total amount of carbon stored in the entire cemetery and sections 10, 33, and 41 from Based on these results, we can attribute Mount Auburn’s increased carbon retention rates to its management practices and abundant planting of trees. Table 4: % of Carbon Sequestered by Rural Cemetery based on % of carbon sequestered annually at Mount Auburn Cemetery and Harvard Forest These results suggest that the more managed a forest is, the more carbon it will sequester. These results also suggest that all forests, managed or unmanaged, are able to sequester considerable amounts of carbon. It is important to note that Mount Auburn’s estimated annual carbon sequestration sets an unrealistic standard. Few forests are likely to receive the intensive management practiced at Mount Auburn Cemetery. Conclusion Death is an inevitable part of life; however, placing an unnecessary strain on a fragile ecosystem is not. In continuing traditional burial practices we are not only disrespecting the Earth but also doing a great disservice to future generations. Left unaltered, current interment practices will make it so future generations do not have the luxury of burying the dead in our present elaborat cemeteries. Green burials offer an alternative to this bleak situation. Utilizing interment practices which are ecologically sound not only allow us to rest in harmony with nature, but also helps to reduce carbon emissions. Since trees are often used as grave markers for natural burials these types of interment practices can improve the tree stands, ecosystems, and carbon sequestration rates of cemeteries. Table 1: Mount Auburn Data Analysis (See Table 3 for results) Rural Cemetery Data Analysis Using the same field methods, the total carbon sequestered in MgC/ha was determined by dividing the total amount of carbon ( kg) by the area of the cemetery (13.1 ha). (See Table 4: row 1: column 2) *Known: Harvard Forest’s (Urbanski et al., 2007) total forest carbon sequestration (aboveground, belowground and soil) is approximately 2.4 times larger than its annual above-ground sequestration (control), its annual above-ground sequestration is 1.04 MgC/ha/yr, and its total carbon storage is 115 MgC/ha).* Harvard Forest was used because carbon sequestration rates were known and it is an unmanaged forest which could be compared to Rural Cemetery. Data PointOperation Amount of carbon sequestered per ha for cemetery in 1996 (See Table 3: row1:column 1) Total carbon divided by 71 ha (area of Mount Auburn) Amount of carbon sequestered per ha in sections 10, 33, and 41 in 1996 (See Table 3: row 1: column 5) Isolate and sum carbon estimates for these sections; divide total carbon by 5.3 ha (area of sections 10, 33, and 41) Amount of carbon sequestered per ha in sections 10, 33, and 41 in 2012 (See Table 3: row 2: column 5) Isolate and sum carbon estimates for these sections; divide total carbon by 5.3 ha (area of sections 10, 33, and 41) Amount of carbon sequestered per ha in each individual section in 1996 and 2012 (See Table 3: rows 1 &2: columns 2, 3 & 4) Isolate and sum carbon estimates for each individual section and divide the total carbon estimate for each section by the area of each section ; Section ha: Section ha: Section ha Annual above-ground carbon sequestration rate for sections 10, 33, and 41 and entire cemetery (See Table 3: row 3: columns 1-5) Divide the difference in carbon storage from by 16 (# of years from ) Estimate of carbon sequestered per ha for cemetery, in 2012 (See Table 3: row 2: column 1) Subtract 1996 total carbon estimate for selected sections (10, 33, 41) from 2012 total carbon estimate for selected sections and divide by 1996 total carbon estimate for selected sections. This suggested that an increase in carbon storage of about 50% from occurred. This estimate of a 50% increase was applied to the entire cemetery’s 1996 data to come up with an estimated sequestration for Data PointOperation The total annual carbon sequestration ( above- ground and below-ground and soil) (See Table 3: row 3: column 1) Multiply 2.4 by the annual above-ground sequestration (for Mount Auburn this would be 1.4 MgC/hayr)* Mount Auburn- 2.4 X 1.4 MgC/hayr = 3.36 MgC/hayr Harvard Forest- 2.4 X 1.04 MgC/hayr = 2.5 MgC/hayr The % of carbon sequestered annually Divide total annual carbon sequestration by total carbon storage (for Mount Auburn this would be the 2012 total for entire cemetery) Mount Auburn-3.36/66.7= 5% ( this means 5% of total carbon is sequestered annually) Harvard Forest- 2.5/115= 2.2% (this means that 2.2% of total carbon is sequestered annually) The carbon sequestration potential of Rural Cemetery (based on Mount Auburn rate ) (See Table 4: row 2: column 2) Multiply total carbon (71 MgC/ha) by the % of carbon sequestered annually by Mount Auburn (5.0%) The carbon sequestration potential of Rural cemetery (based on Harvard Forest rate) (See Table 4: row 3: column 2) Multiply total carbon (71 MgC/ha) by the % of carbon sequestered annually by Harvard Forest (2.2%) Total Carbon71 MgC/ha Carbon sequestration potential based on Mount Auburn annual % of carbon sequestration 3.6 MgC/hayr Carbon sequestration potential based on Harvard Forest annual % of carbon sequestration 1.5 MgC/hayr Advisors: Dr. Allison Dunn, Dr. Patricia Benjamin and Dr. Stephen Healy Table 2: Calculating the amount carbon sequestered from the atmosphere by Rural Cemetery based on the % of carbon sequestered annually by Mount Auburn Cemetery and Harvard Forest (an unmanaged forest) in Petersham, MA (See Table 4 for results) Mount Auburn Cemetery, Cambridge, MA (a managed forest) Rural Cemetery, Worcester, MA (an unmanaged forest) ha= hectare MgC/hayr= Mega grams of carbon per hectare per year; 1 mega gram= 1 metric ton or 1000 kilograms; 1 hectare= 2.47 acres.