In March, pictures of cherry blossoms—Japan’s famous pinkish-white flowers—flood the Internet. People travel long distances to see these flowers, drawn by the vibrancy they bring to the season. Cherry blossoms are also among the most documented flora, and historical records reveal a worrying shift in their flowering pattern.

Documents have revealed that, in Japan’s central city of Kyoto, cherry blossoms have been blooming earlier in the past few decades compared to the previous 1,200 years. For instance, in 2024, they bloomed on March 17, which is the second-earliest on record. Observing the seasonality of trees not only indicates their health but also larger issues such as how climate change is affecting flowering patterns, says Geetha Ramaswami, lead at SeasonWatch, India. 

People pass by trees every day but rarely pause to observe them. From the change in the hues of the leaves to the emergence of fruits, every pattern gives a glimpse into climatic conditions. SeasonWatch, a citizen-science project that started in 2010 as a three-way partnership between the Nature Conservation Foundation (NCF), Wipro Foundation and the National Centre for Biological Sciences, focuses on monitoring the seasonal phenology of trees. This helps understand how a changing climate impacts biodiversity.

“When the life pattern of a tree changes, everything that depends on it—the insects that pollinate the flowers or birds that eat the insects—are affected. Their life cycles are impacted,” Ramaswami explains. “Trees are the pulse of changing seasons,” the SeasonWatch website states.

Over the last 15 years, the project has engaged 2,648 citizens who have recorded more than 833,700 observations of about 150,000 trees, such as Purple Bauhinia, Indian coral, and Devil’s tree. SeasonWatch has an Android app where people can upload their observations.

Image credit: Photo by Geeta Ramaswami. Provided to Greenauve.

Citizen science projects play a crucial role in society, emphasises Ramaswami. “Often, science and scientific research are not accessible to everyone. Citizen science breaks the barriers between science and people and involves them in understanding the problems as well as brainstorming solutions”, she adds.

For instance, when people hear about climate change, there is an omnipresent picture of polar bears and melting glaciers. But most of the research and the crises, such as wildfires don’t receive the same visibility. “Once you start noticing a tree in your backyard and observe the changes it has been going through every year, you realise climate change is affecting biodiversity in your home and neighbourhood”, Ramaswami explains.

In Kerala, India, the Indian laburnum tree is associated with the Malayali New Year, which falls in mid-April, as it blooms during that time. However, in the past six years, people have noticed that the flowers no longer bloom during this period, Ramaswami says. “It really hit home for many when they had to buy the flowers from markets or use plastic ones,” she adds.

To encourage more people to observe local biodiversity, SeasonWatch frequently conducts tree festivals. During these events, people participate in challenges to record as many tree observations as possible. These include themed challenges such as observing trees of particular species. They also run the Campus Phenology Network, a program for undergraduate students. It allows them to participate in internal challenges and compete with other colleges.

Since its inception, SeasonWatch has focused on engaging school students through various tree-related activities. Until now, students from about 3,000 schools have participated in these. “Our program in schools is largely driven by teachers who want children to have more hands-on experiences and not just get lost in textbooks. The idea is to ensure they have a practical understanding of what happens in nature,” says Ramaswami. Many teachers have told SeasonWatch that this experience has transformed how children perceive and interact with nature.

For example, in 2020, Sujatha M, a teacher at Government Upper Primary School in Kongad, Kerala, explained how she regularly took her students outside to observe a tree. One day, the children saw that the tree was full of caterpillars, which they found unsettling and ran away. But the teacher kept bringing them back to the tree to watch the caterpillars transform into pupae and, finally, butterflies. “They went from being scared of them to being curious”, Ramaswami says.

SeasonWatch also hosts tree walks and training workshops on how to identify plants and integrate flora in nature education. “When people get involved in citizen science, it’s simply for the love of birds, insects, trees and other life forms. They observe and record to share knowledge. It still surprises me how committed they are and how it can change the way people interact with the nature around them”, Ramaswami concludes.