Friday, May 10, 2013

Spring Phenology


            We recently completed a lab in my forest ecology class about the timing of tree budburst in Jericho Research Forest.  The idea of the study was to look into how different trees respond to the onset of additional light in the spring.  When walking through the forest in early spring, it is very clear that different species are on their own schedules in terms of blooming; the first week we were out in the forest, approximately 75% of the trees showing signs of bud development were red maples.
            Such differences in tree phenology show how each species has a niche within the plant community.  Trees that bloom early in the season are able to absorb some extra light energy without the competition of the other canopy trees later in the season.  This is especially important for species that aren’t dominant trees in the overstory.  On the opposite end of the spectrum, there are also species that hang on to their leaves late into fall as to soak up the final rays of light before winter. Species such as American beech often won’t even release all of their leaves, and some stay on the bud for the duration of winter.
            We found higher amounts of saplings and seedlings budding than canopy trees.  While this is just speculation, I think that this could be related to the higher levels of light energy that they can receive earlier in the season, as the canopy trees aren’t shading them from the sun yet.  By budding early, they can take advantage of as much solar radiation as possible before they are stuck in the under the canopy once again.
            An interesting wrinkle to this experiment is the effect that climate change has already begun to have on spring phenology.  Studies of other New England forests over the course of 10+ years have shown that budburst is becoming slightly earlier every year.  With longer growing seasons, trees will be able to keep their leaves for a lengthier period of time.  This additional growing season will likely have an effect on the habitat range of different tree species.  

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