table rocks-an oregon natural area

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TABLE ROCKS IN OREGON-A BOTANICAL HIKE Linda R. McMahan Extension Botanist and Horticulturist Oregon State University, Yamhill County [email protected]

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Located near Medford, Oregon, this popular natural area is a good botanical hike in many seasons

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Page 1: Table Rocks-An Oregon Natural Area

TABLE ROCKS IN OREGON-A BOTANICAL HIKE Linda R. McMahan

Extension Botanist and Horticulturist

Oregon State University, Yamhill County

[email protected]

Page 2: Table Rocks-An Oregon Natural Area

Here I am at the topThis is a hike I’ve wanted to do for a long time, and I got the chance this November during a visit to Medford, Oregon. In the background you can see Medford and Central Point. Nearer the rocks is the Rogue River as it winds its way through the valley. I climbed the Upper Table Rock. Yes, there are two, but this was the shorter hike, so having to drive home for several hours afterwards, I chose accordingly.

Page 3: Table Rocks-An Oregon Natural Area

Can You See my CarWe are about 800 feet above the valley floor. My car is a tiny speck in the parking lot located at about 2 o’clock in the picture. According to an article(http://www.npsoregon.org/kalmiopsis/kalmiopsis03/seevers_borgias.pdf), the “tables” were created by erosion. Originally lava flows had filled in the basin, perhaps 9.6 million years ago. Gradual erosion washed away most of the softer flow materials, but the Table Rocks were harder material called andesite, and remained.

Page 4: Table Rocks-An Oregon Natural Area

Lava FeaturesThe volcanic orgin was evident everywhere, from the tumbled rocks making up the base around the trail, to this rock formation by the trail.

Page 5: Table Rocks-An Oregon Natural Area

Erosion is still going onAt the inward edge of Upper Table rock, breakup of the plateau still occurs. Huge chunks of columnar andesite are slowly breaking away. Each plateau is in a horseshoe shape. The shape apparently was caused by former meanders in the Umpqua River.

Page 6: Table Rocks-An Oregon Natural Area

Oregon White Oak, Quercus garryanaBeing a botanist, I was naturally interested in the vegetation. Actually, every hike for me turns into a botanical experience.

Fall color for the oaks was very nice, at least for Oregon. Lichens and mosses were beginning to swell from the first big rains of the fall season. Fortunately, the day’s rain most held off until after I finished the hike.

The ecosystem also has the California black oak (Quercus kellogii), but I didn’t happen to snap any pictures of them to share.

Page 7: Table Rocks-An Oregon Natural Area

Mistletoe on oak, Phoradendron favescens

Just like oaks in the Willamette Valley to the north, Oregon white oak on the reserve have lots of mistletoe. Mistletoe is a partial parasite which is able to produce energy through photosynthesis but needs the tree to obtain other nutrients.

The land on the two Table Rocks has mostly been preserved by the Bureau of Land Management (BLM) and The Nature Conservancy. At one time, there were possible plans for development, which fortunately, never materialized.

Page 8: Table Rocks-An Oregon Natural Area

Poison oak, Rhus toxicodendronA namesake of oak also caught my attention. There was plenty of it—the beautiful three-part leaves were gone, however. I only recognized it by the characteristic stick-like growth form and the berries.

Page 9: Table Rocks-An Oregon Natural Area

More poison oak

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Excuse the fascination for a sometimes troubling native plant, but on the way up the trail, I kept wondering why there were sticks coming out of the ground. On the way down, I finally figured it out. Fortunately, I didn’t check it out too closely.

Page 10: Table Rocks-An Oregon Natural Area

Madrone, Arbutus menziesiiRecent rains brought out the magnificent color of madrone bark. Older bark peels off in layers as the tree grows. Many of the madrones in the preserve have recovered after fires, which have periodically visited the site for many generations of plants.

Page 11: Table Rocks-An Oregon Natural Area

On theground. . .Shredded madrone bark and fallen leaves pattern the ground beneath the trees.

Page 12: Table Rocks-An Oregon Natural Area

White-leaf manzanita, Arctostaphylos viscida

Large manzanita shrubs dot the landscape, such as this one under a madrone at the edge of the plateau. The evergreen foliage is excellent—I wish mine would grow like this, but I don’t have the good drainage and warmer climate that they require.

Page 13: Table Rocks-An Oregon Natural Area

Wedgeleaf ceanothus, Ceanothus cuneatus

A major component of this fire-maintained ecosystem, the wedgeleaf ceanothus is beautiful much of the year. Blooms are spectacular, but those come at another time of year—not in November! Guess I will just have to return.

Page 14: Table Rocks-An Oregon Natural Area

View of the top!At the top of each Table Rock, visitors are greeted by a massive flat area with a thin covering of soil that has accumulated over time. Fall vegetation is mostly grasses, mostly alien ones at that, but in the spring, it is apparently a much different story—that’s when most people visit who are interested in the plants.

The inset shows the moss, a major part of the plateau vegetation.

Page 15: Table Rocks-An Oregon Natural Area

Vernal PoolsJust this view shows different patterns of vegetation. Indentations in the surface allow the accumulation of water in pools that dry up in the summer. A successful of colorful flowers, sometimes in rings around the water, draws visitors in the springtime. The pools are fragile and becoming more rare as special areas like these are disappearing.

Page 16: Table Rocks-An Oregon Natural Area

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From where I am standing, you can see the other end of the horseshe shape for Upper Table Rock. In the distance is Lower Table Rock. Next time, I will come armed with the plant list and my identification tools.

Page 17: Table Rocks-An Oregon Natural Area

Time to plan your own visit?

© 2011 Oregon State University. All photos are by the author. You may use of the presentation for educational purposes. For other uses or more information, please contact:

Linda R. McMahan

OSU Extension Service

[email protected]