February has had its fair share of snow, but there are already signs of spring. Just look at the trees! No, you won’t find green leaves quite yet, but if you look closely, you’ll see the buds.
Buds are made in the fall during an early stage of preparation for winter dormancy. Plants create tissues that will be ready to produce leaves, but can survive or even require the harsh cold of the winter season. Dormancy begins and ends as a response to daylight along with other environmental factors. As the length of daylight decreases, plant hormones bring about deeper and deeper stages of dormancy until the tree is prepared to survive the winter.
In late winter, once the daylight has recovered enough, growth hormones are activated and the plant starts to come out of dormancy. Once the hormone cycle restarts the tree will react to temperature, and just a short warm spell will cause the buds to start to move. Even now, in the midst of snowstorms, some plant buds show signs of growth, like the white lines dividing the scales on this bud. Over the next few weeks the bud will continue to stretch until a leaf appears and the bud “bursts.”
Several school groups come to Drumlin Farm to help us track bud burst at the sanctuary with the Harvard Forest Buds, Leaves, and Global Warming program, which has been tracking bud burst for twenty years. Students tag branches and observe the buds week to week to document the timing of changes in the tree buds. Trends have shown that buds are bursting 2-3 weeks earlier than they were decades ago.
Here at Drumlin Farm, one natural reaction to bud bursts is seen in the vernal pools. Once the trees around the pool have buds and show leaves, they draw water from the ponds. This often lowers the pond level, depending on other environmental factors. Does the early budding affect the life cycle of pond organisms that depend on our vernal pools? We don’t know, but many school groups who participate in ponding programs record data regarding the organisms living in our vernal pools, which may give us the data to answer this question in the future. You can find Drumlin Farm’s data on the Harvard Forest website.
Bud burst tracking can be done in your very own backyard. Tag a branch or two, and visit that location every few days to observe the small but significant changes that occur far before green leaves appear. Take a picture each time you visit, and compare the buds over time. Watching the buds burst will show you that spring comes much sooner than you think. You can keep a journal of your findings so you’ll have something to look back on next year!