A few weeks ago, the British Broadcasting Company (BBC) wrote about a report claiming that some of the fruit from native trees in Britain are ripening anywhere from 13 to 18 days earlier than they did a decade ago. The report was from Nature’s Calendar, a data collection network in the United Kingdom. While the cause isn’t specifically known, many believe it’s due to a change in climate.
What does a change like this mean to the earth as a system?
Scientists are interested in studying the connections between the different Earth processes – from how greenhouse gases are trapped in the atmosphere to biological processes occurring on land. It is important to understand these intricate connections to attempt to paint a picture of what the climate will look like in the future . This includes the connection between weather and climate to biological processes, such as animal migration or a plant’s life cycle. This is known as phenology, or the study of a living organism’s response to seasonal and climatic changes in the environment in which they live. Seasonal changes include amount of precipitation, temperature, variation of the amount of sun light, and other life-controlling factors
As you may know, The GLOBE Program has a suite of phenology protocols to examine the response of native species to changes in season. For GLOBE students and teachers familiar with phenology measurements, you may recognize this as the period between Green Up and Green Down, which are two of our protocols. A consistent change in the length of time between Green Up and Green Down can indicate a change in climate.
While there were only two types of fruits examined in this study, rowan berries and acorns, all fruiting plants go through similar life cycles and can be related to Green Up and Green Down once the plant has reached maturity. Once budburst and leaf growth has occurred for a given growing season, flowering will begin. Flowering may not be easily recognized, because not all plants show with large, fragrant flowers. For example, when the oak tree flowers, it looks something like this:
Flowering oak tree, from mainenature.org
Then, either due to the wind or insects, the flowers are pollinated and begin forming fruit. Keep in mind that just because it’s called a fruit doesn’t mean it’s actually a fruit for a human to eat, as some can be poisonous! Once these fruits ripen, they fall off and begin to form a new plant through germination and maturation.
Fruit ripening occurs typically during a specific season due to the right combinations of conditions. If one or more of these conditions were to change, then it can be assumed that the ripening time would shift in one direction or another. In the case of the United Kingdom, there is a correlation between the ripening dates and April temperatures. By having warmer surface temperatures in April, flowering is occurring sooner, and thus so is fruit ripening. There is hesitation to say that it is directly tied to temperature, but may just be a result of more sun as well as longer and warmer summers.
The major concern with the changes of ripening dates is the effect it will have on various animals that rely on fruit ripening to lead migration or use for winter food.
How can GLOBE data help answer these types of questions? First, it’s important to begin by taking air temperature, precipitation, and cloud measurements. Each of these factors is important to the growing season. Next, taking Green Up, Green Down, and Budburst measurements are also important, because it can give scientists an idea if there are shifts to the growing season as a whole.
With this particular study, only 10 years of data were used. GLOBE, however, has been around for almost 17 years! With such a rich history, it could provide additional information that could potentially be used to answer these questions. And while this report was for the United Kingdom, it can easily be applied to any country or region in the world that has native, flowering plants!
If you’re a GLOBE teacher, have you used any of GLOBE’s phenology protocols? We’d love to hear if you’ve seen any changes in your data collection over the years – please leave us a comment or email us!