Thursday, May 26, 2011

Fallen Trees and Browse Lines

I managed to find time between the storms to get into the woods to check for fallen trees. No live trees had gone down, but there were several dead trees that had changed from a vertical to a horizontal orientation. The frequent rains we’ve been having allow the dead trees to become saturated with water. This can increase the weight of the log by several times. The added weight, coupled with strong storm winds, makes the dead trees much more likely to fall.

Something I found much more noticeable than the newly downed trees was the browse line created by Whitetail Deer foraging the Sugar Maple understory. A browse line is a phenomenon that occurs when herbivores consume all of the vegetation in the woods between the ground and the level of their highest reach. A condition is created where a clearly visible line is formed between the leafed and the leafless areas. This is generally an indication that a population of animals is reaching a density that could severely stress the local food supply. It’ll still be a while before we have starving deer at Blue Jay Barrens, but this is a sign we’re headed in that direction. The concern is what will happen to the local plant populations as the deer are forced to eat any palatable greenery they can find.

Trees falling to storms are what opened the woodland canopy and allowed in enough sunlight to encourage a flush of young Sugar Maple trees. The maples are fighting to fill those few sunny openings in the canopy.

A few hundred feet away, I found some more fallen trees in an area that has virtually no understory shrubs or trees. There are Sugar maple seedlings in this area, but they don’t receive enough sunlight to continue their development. This is what the first area looked like 25 years ago.

Sometimes it doesn’t take a big change in the canopy to trigger a noticeable shift in the structure of the woodland floor. Even though most of this is outside my control, it’s nice to know how things are likely to respond to particular events. Browsing deer, heavy rain and windy weather will continue and I will continue to look for the positive side to each event.

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