Thursday, January 14, 2010

Some Cedar Observations

Eastern Red Cedars are great snow catchers. The wide branches of tightly packed, scaly needles do a wonderful job of filtering falling snow from the air. Cedars growing in dry, open areas develop stout trunks with strong branches that grow the entire length of the tree. This gives them the ability to bear the weight of heavy snow loads without much structural damage.

Well branched cedars growing in a deciduous woodland began their lives when the forest canopy was more open. A heavily logged woods often gives cedars the chance to begin growth in a manner similar to that displayed in an open field. As the woodland regrows, the cedars become more shaded and the side branches become weaker and more open. Eventually, the deciduous trees will become so tall and full that these cedars will die for lack of sunlight.

In a deeper soil with more moisture, closely spaced cedars grow very quickly. The canopy closes when the cedars are still small and the shaded conditions prohibit branches from developing. The trees are in a constant struggle to keep their top growth in a position to collect sunlight and the result is a thick stand of tall, thin trees.

Tall and thin does not equal strong. The weight of snow caught by the tree tops becomes too much for the trunks to handle. Bowed trees become common in this situation. Once bent, the trees will never straighten. The top branch of the tree produces a chemical that identifies its dominance and keeps side branches from trying to become the tree top. The shift of the tree top to a more horizontal position disrupts the effective distribution of the chemical and allows branches on the upper side of the curve to grow more rapidly and compete for the leader position. This flush of growth makes the top even more effective at catching snow and increases the chance of more bowing in the future.

The stand of tall, straight trees becomes a tangled mess. The bent and fallen trees eventually die, but not all of the cedars will succumb to the perils of heavy snow. Some trees will remain standing tall. The reduced competion will allow them to grow more quickly and they will one day become some impressive monsters. The cedars will have a few decades of prosperity, but events are already in motion that will mean their demise. The bowed trees have allowed in enough sunlight that young Sugar Maples and Tuliptrees have sprouted in the stand. Before the cedars can once again close the canopy, these deciduous sprouts will find their way to the sunlight and eventually overtop and shade the cedars.

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