These questions will be answered from the article Geobotany by Jane Forsyth.
1. The geology of Ohio (if not regarded too closely) may be divided neatly into two parts. Contrast these two parts in terms of their geographic location, types of underlying rocks and their physical properties, and the landscape/topography that characterizes each.
The western part of Ohio would be considered underlined by limestone. This type of rock, including dolomite, is nonresistant in humid climates. The landscape in this part of Ohio is flat due to erosion of rocks that began about 200 million years ago.
The eastern part of Ohio can be considered mostly underlined by sandstone, which is a resistant rock. This type of rock is throughout the Cleveland area and underlain by shale. The landscape in this part of Ohio is steep-sided sandstone hills and in the Cleveland area has sandstone capped hills.
2. The reason for the difference in kinds of rocks is not difficult to understand. Describe the original sequence of sedimentary rock strata (three types in order from top to bottom), an arch that formed 200 million years ago noting where the crest of the arch was located compared with the low-lying toe of the arch, and an important river system that occupied OH for a long time. (Be sure to give the name of the river, state about how many years it flowed and what effect it had upon the landscape. What curtailed the activities of the river?)
The sequence of sedimentary rock strata goes from top to bottom limestone, shales, and then on the bottom sandstone. An arch was formed about 200 million years ago because of the pressure of all these layers. Erosion cut the arch deepest where it stood the highest which exposed its oldest rocks. This was along the crest that extends north-south through western parts of Ohio. Erosion of limestone, in the western parts of Ohio, and sandstone, in the eastern parts of Ohio, were because of the Teays River. This river flowed across most parts of Ohio about 200 million years ago. The streams activities were curtailed by the advance of the Ice Age that happened less than a million years ago.
3. Pleistocene glaciers invaded OH a few hundred thousand years ago or less. What feature of the landscape slowed the glaciers and so caused there to be a glacial boundary cutting across OH?
The glaciers were slowed down by the steep-sided sandstone hills that were in the Eastern part of Ohio. This caused a glacial boundary that cut across no further than Canton, Ohio.
4. Describe “glacial till” in terms of its general composition (a definition of till), and how it differs in eastern and western OH.
The glacier had two kinds one being unsorted mixture of sand, silt, and clay whereas the other part is boulders which is called till. A till is a boulder that will occur all over the glaciated parts of Ohio as a continuous blanket. The glacial till in the eastern parts of Ohio contain small amounts lime and clay. Comparing this to the western part of Ohio, that has large amounts of lime and clay.
5. Contrast the basic substrate for plants in western and eastern OH in terms of drainage, aeration, pH (limey versus acid) nutrient availability.
The western parts of Ohio would be considered a fen which flushes water that comes from rain or springs. The water is alkaline to neutral because of the limestone. Aeration is introduced when the water gets flushed out.
The eastern parts of Ohio would be considered a bog which water mostly will escape through evaporation. The water in bogs are acidic because of the decaying plants. There is no aeration introduced because the water does not get flushed out.
6. Name 5 species of trees/shrubs that have a distribution generally limited to limestone or limey substrates (such as Ohio’s Lake Erie islands).
Blue ash,Hop hornbeam, Hackberry, Fragrant sumac, Chinquapin oak
Pictures of those 5 species:
7. Name 5 species of trees/shrubs that have a distribution generally limited to high-lime, clay-rich substrates developed in the thick glacial till of western Ohio.
Sugar maple, Beech, Red oak, Shagbark hickory, White ash (slightly wetter places)
8. Name 5 species of trees/shrubs that have a distribution generally limited to sandstone hill of eastern OH.
Shrubs: Mountain laurel, Huckleberry-blueberry, Trailingbutus
Trees: Chestnut oak, Sourworm
9. What is the major determinant of the distribution of each of these species: a) sweet buckeye (contrast with hemlock), b) hemlock (contrast with sweet buckeye, c) rhododendron?
Sweet buckeye is apart of a species that does not occur within the glacial boundary. The reason for this is unknown, but may be because of repopulation problems of clayey and high-lime tills. Climate might be a reason for the plant not extending even as far north as the glacial boundary in eastern Ohio.
Hemlock’s distribution is present in the eastern un-glaciated part of Ohio. However, it can also extend to the northern parts of the glacial boundary. This tree can survive in moist environments that are continuously cool, which can be seen in the deep valleys of sandstone as well as cool spring water.
Rhododendron in mainly in the southern part of Ohio. This tree is one of many that migrated from northern Ohio to the southern parts of Ohio through the preglacial Teays River system. The distribution of this tree suggests that it belonged to mesophytic associations of Ohio.