Science progresses in many ways. Sometimes, scientists use the written work of other scientists to help them think through a question. This process is called a literature review, and it is common in all scientific work. Scientists must know what other scientists have discovered so they can advance the discoveries further. When you do a research paper for school, you are often doing a literature review, just like scientists. Sometimes, they do the same experiment as other scientists to see if they get the same results.

Social scientists study the thoughts, feelings, beliefs, or actions of individuals or communities. In social sciences, scientists sometimes use case studies to better understand a question or idea. A case study is an examination of a single case as an example. Think about a student who wins a regional science fair. A social scientist might study this one student’s experience as an example of other science fair winners’ experiences.

In this study, the scientists were interested in ways that people remember past events and people who have died. The scientists wanted to explore why people plant trees and flowers to remember events and people. The scientists became familiar with what other scientists had written about why people plant trees and flowers. The scientists developed a possible explanation for why people plant trees and flowers to remember events and people. Then, the scientists conducted two case studies to investigate whether their ideas made sense in those real situations.

The natural environment means many things to people. Some of these meanings are revealed after a natural disturbance, such as a flood or a hurricane, or after a human caused tragedy. Trees, flowers, and other plants are often planted so that events or people can be remembered. The scientists in this study were interested in how planting trees, flowers, and other plants helped people adjust after a human caused tragedy or a natural disturbance. The people who designed the 9/11 Memorial in New York City, for example, described their design in this way:

“Visitors will leave the everyday life of the city and enter into a sacred zone defined by a dense forest of 416 oak trees. Above the limbed-up trunks, a canopy of leaves will provide welcome shade in the heat of the summer and seasonal color in the fall. In the winter the sun will cast shadows through a light tracery of bare branches, and in spring, the trees will express the renewal of nature (figure 1).”

In New York City, a planning committee asked citizens what kind of memorial they would like to see. The citizens made comments. Using these comments as a guide, the committee selected a team to design the 9/11 Memorial. A company was hired to plant the trees on the memorial site. Often, however, ordinary people get involved by planting trees and other plants to remember an event, a person, or even many people (figures 2a and 2b). Take a moment to think about your own life. Have you ever planted a tree, flower, or other plant to remember someone or something? If you have not, do you know anyone who has? What makes planting a tree or other plant for this reason special?

The scientists in this study were interested in what communities do after a natural disturbance or human-caused tragedy. In particular, they were curious about planting trees, flowers, and other plants as a way to remember the event or the people who were injured or lost. The scientists noticed that people surviving a human-caused tragedy or natural disturbance often planted trees, flowers, or other plants as a way to remember.

First, the scientists read what other scientists had written about this kind of tree and flower planting. Then, the scientists developed their own ideas about why people plant trees and flowers in memory of events and people. The scientists also developed ideas about what benefits tree planting and other similar actions have for the community.

The scientists thought that tree and flower planting might be a way for people to remember an event as a community of people. The scientists thought that trees, flowers, and other plants symbolized life and growth for the planters. Using trees and flowers as symbols might be a way for people to express hope and strength for the future. Tree and flower planting, therefore, may help communities be strong following a loss. The scientists thought that tree and flower planting was one way communities adapt to loss so that they can move forward while remembering the past (figure 3).

The scientists also thought that other things happen when people plant trees and flowers after a natural disturbance or human tragedy. The scientists thought that, without realizing it, people and communities learn new things by coming together. Some of the things they learn might be from people sharing the knowledge they have with others. Some of the things they learn might be learned as a group, without anyone teaching. When someone teaches or a group learns together, existing knowledge is shared with others or new knowledge is created by the community.

The scientists wanted to find out if their ideas might be correct. They conducted two case studies of communities that had survived a loss and had planted trees or flowers in memory of their loss.

Recall that the scientists started their research with a literature review. (Read “Thinking About Science” if you have not already done so.) This review helped the scientists to develop ideas about why people plant trees or flowers in memory of a person or an event. These ideas, in turn, helped them focus their efforts to answer their research questions.

For their case studies, the scientists selected tree and flower planting after two events. The first event was in New York City. New York City lost 2,819 lives in the terrorist bombing of the World Trade Center on September 11, 2001. The second event occurred in New Orleans, Louisiana. In New Orleans, 1,836 people died and more than 850,000 homes were destroyed during, and in the aftermath of, Hurricane Katrina. The hurricane made landfall on August 29, 2005. The scientists studied tree and flower planting efforts by individuals and communities after these two events (figure 4).

The first effort the scientists studied was a national program. The Forest Service started this program. The program was called the Living Memorials Project. The scientists found information on 687 communities across the United States that planted gardens to remember those lost on September 11. The scientists asked questions of people in 113 of these projects. The scientists wanted to understand why and how people planted trees, flowers, and other plants to remember the events of September 11, 2001 (figure 5).

The second effort the scientists studied was actually that of a number of community groups that worked together. People in these groups planted more than 6,000 trees in New Orleans’ hardest hit areas (figure 6). These groups formed after Hurricane Katrina. The groups’ goal was to help New Orleans recover from the destruction and loss caused by the hurricane. The scientists asked questions of group members and citizens who planted trees as part of this effort.

The scientists audiotaped all questions and answers. The scientists kept the identity of each person who answered questions confidential (secret). The scientists listened to the tapes and typed the questions and answers into a computer. They then sorted the answers into categories so that they could understand better what they had been told. The scientists observed people planting and tending the gardens. The scientists also took photos while people worked in the gardens. Using observation and photos, and by asking questions, the scientists collected information about why people plant memorial gardens.

The scientists discovered that people felt planting trees, flowers, and other plants helped them heal from their loss. In New York City, some people planted sunflowers and daffodils (figure 7). One of these people said—

“There is a power and healing that comes from digging in the dirt, planting new life, and nurturing its growth….Sunflowers make sense as one tall way to remember life and make it a bit better.”

In New Orleans, people found tree planting was a way to remember what they had lost. One person said—

“These trees we are planting might be a reminder of what we lost, so that we don’t ever forget it and don’t let that happen to us again.”

The scientists discovered that people living in these communities learned how to plant and take care of the trees and flowers from professionals who work with plants and trees. This activity made people feel like they were rebuilding the community. These people created communities of practice. These communities of practice shared what they learned with others. This action served to strengthen the sense of community. The scientists believe that, after a loss, people feel an innate desire to plant trees, plants, and flowers.

In this research, the scientists thought that communities use tree and flower planting to help adapt to a loss. After people plant trees or flowers, they share their gardens with others. Working together creates communities of practice. Communities of practice enable people to continue working together.