Thursday, March 26, 2009

Hemlock and Spruce and Pine, oh my!

There are several coniferous tree species found in Eagle Creek Park; for instance, the long magestic row of tall Norway Spruce (Picea abies) trees with their graceful upward arching branches along the main road by the Ornithology Center. They were originally planted by the Lilly family, and there are several around the EDC as well. As the name suggests, Norway Spruce is native to Europe. There is a White Spruce, Picea glauca, which is native to Indiana, but I've not found any growing in the park.Spruce needles are very stiff, and quite sharp. Folks who celebrate Christmas with a live spruce tree usually have a few uncomfortable prickly moments setting them up!The cones of the Norway Spruce have densely packed scales, and are 6+ inches long (cones of White Spruce are much smaller - less than 3 inches). Squirrels like to strip them of their scales and eat the seeds, leaving the central stem of the cone behind.
If Norway Spruce has the biggest cones, the Eastern Hemlock (Tsuga canadensis) has the tiniest - these little doobers are only about an inch long.
Eastern Hemlock has flat, rounded needles, soft and flexible, rather than stiff and sharp, with two whitish lines on the underside. This is not the same hemlock that killed Socrates (the poison he drank was made from an herbaceous plant that looks a bit like parsley - Poison Hemlock, Conium maculatum) so don't worry about touching and handling Eastern Hemlock, it won't bite! In fact, pioneers often made tea from the needles, which, like most conifer needles, are high in vitamin C. Deer also find the Hemlock needles tasty; the trees in the park are all browsed as high as a white-tailed deer can reach.
Eastern Hemlock prefers cool and humid growing conditions, and unlike most other conifers it can grow in the shade. Most of the trees in the park were probably planted, but they grow naturally in ravines in southern Indiana. These cool, humid microclimates became refuges for hemlock trees when the glaciers retreated long ago, and Indiana became too warm and dry for them to survive in more upland forest.
Next we have the cones of the Eastern White Pine (Pinus strobus) - similar in size to Norway Spruce, but the scales are much less densely packed, and they are often adorned with white bits of sap on the ends. White Pine is native to Indiana, but the original range was only in a few small pockets - the trees in the park were probably planted. Check out the "Native Trees of Indiana Riverwalk" for some excellent range maps of Indiana trees:
White Pine holds the record of being the tallest tree in eastern North America; pre-colonial trees were reported to reach over 200 ft tall, and the current record holder is just over 180 ft. The tall, sturdy trunks of the White Pine were in great demand during colonial times to be turned into masts for the ships of the British Royal Navy.
There is a large White Pine growing near the deck at the Ornithology Center, and one at the edge of the Grasshopper Field by the EDC.
Needles of the White Pine are long and slender, and grow in clusters of five. Quite conveniently, the word "white" has five letters, making this fact a little easier to remember. The needles look sharp, but they are actually quite soft and flexible.
The other common pine tree in the park is the Virginia Pine (Pinus virginiana). Its needles grow in clusters of two, and the needles are slightly twisted or spiraled. There are several stands of Virginia Pine planted in the park - you can find them growing along both the Pin Oak Loop and the Cabin Loop Trail by the EDC. Virginia Pine is native to Indiana, but only occurred naturally in the south, along the Ohio River.
Most of the Virginia Pine trees in the park look rather worse for wear. It is hard to even tell they are pines in most cases, unless you look to the very top and see the needles. Virginia Pine is shade intolerant, and has a very short lifespan - only 60 to 90 years - and that is about how long ago they were planted. Norway Spruce can live a little longer, 100-200 years, and White Pine and Hemlock can reach ages of 300 to 400+.
The cones of Virginia Pine are medium in length, around 3 or 4 inches, and have a sharp thorny spur on the tip of each scale.

1 comment:

Anonymous said...
This comment has been removed by a blog administrator.