Budburst Research

What is Phenology? What is Budburst?
Budburst is an example of a phenological cycle. Phenology is the study of seasonal changes. Budburst is when the tree buds pop open. There are two kinds of buds on the tree - flower buds and leaf buds. The timing of budburst is influenced by temperature or moisture. Budburst observations can be used to examine regional and global vegetation patterns, interannual variation, and vegetation responses to climate change. Students will observe when budburst occurs on selected trees.

When will the tree buds burst?
MSSD data

Tree species	bud type	2002	2007	2008	2009	2010
Silver Maple Acer saccharinum	flowers	not observed	Mar 11
Silver Maple Acer saccharinum	leaves	April 12-18	April 11-19
Crab Apple Pyrus coronaria	flowers	not observed	March 17
Crab Apple Pyrus coronaria	leaves	March 1	March 17

Predict budburst
What day do you think the buds will burst on these two trees in 2008? Write your prediction:

Observe the buds every day

Silver Maple flower buds, spring, 2007

1. Go to the trees and choose a bud that you can see easily.

2. Put a tape near the bud so you can find it again.

3. Take a picture of the bud.

4. Observe the bud every day. Write down if the bud is dormant, swelling, or burst on the data sheet.

Bud biology
In the space below make a precise drawing of a bud and identify the parts.

How Scientists will use these GLOBE data

Even though the timing of budburst will vary between years, budburst occurs when the trees sense certain temperature or moisture conditions. In other words, the trees respond to the local environmental and not to the dates on a calendar. The conditions the trees require in a locality remains fairly constant between years.

Using your observations of budburst along with your temperature and precipitation data over time, scientists will be able to accomplish four different objectives.

First, we will map annual dates of budburst across the continents.
Second, we will establish the weather patterns that control phenology in your area and across the world. Over time, you will be able to find out if your growing season responds to temperature or moisture. Using all the GLOBE data, we will be able to map areas of the world where the growing season is controlled by temperature and where it is controlled by moisture.
Third, we will develop a better understanding of how global vegetation responds to interannual climate variability.
Finally, we will compare the data from the GLOBE Phenology Protocol with satellite observations of changes in greenness in order to better understand how to interpret these data.