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Tour Stop 5: Tree Rings

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Stop 5: Tree Rings Wireless Wilderness Audio Tour

Fallen pine tress at LCNP.

Some of the trees in our forest are very old and have lived through many hard times, naturally speaking. There have been multiple hurricanes and several droughts in the last 100 years. In 2011, severe drought wreaked havoc on some of our Loblolly Pine trees like the stump of the one before you. These trees were not removed but were left to provide habitats for insects, amphibians and other creatures and to decompose, returning nutrients back to the soil. But now, the Houston City Parks and Recreation Department has cut the snag down so that it wouldn’t fall across the path. The cross-sawn trunk of the pine tree in front of you also provides a window into the past.

Each year, a layer of new wood is added to the trees, between the old wood and the bark on the outside of the tree. As these new layers are added, the tree trunk and branches grow in diameter.

Each layer of new wood forms a visible ring that you can see in a cross section of the trunk. Because this happens every year, one can estimate the age of a tree by counting its rings. Look closely at the rings-you’ll notice that they are actually two colored. The early wood, the light-colored band, is laid down in the spring and early summer when water availability is the highest. Late wood is produced later on in the summer and in the early fall. Late wood cells are somewhat smaller than early wood cells and have a much thicker cell wall, resulting in a darker color.

The annual rings of a tree provide scientists with a snapshot of the environment during the life of the tree. Generally, plenty of rain means wide rings and drought means narrow rings. Scientists have also been able to identify lightning strikes, earthquakes, insect infestations, and climate change, based on the appearance of tree rings.

So, how old do you think this tree was before Hurricane Ike brought it down in 2008?

Tree rings at LCNP.