Ocmulgee Flats   Jess Riddle   Jan 14, 2006 09:04 PST  Ents, After a tip from Matt Elliott, my dad and I decided to explore Ocmulgee Flats for large trees. Ocmulgee Flats lies at the western edge of the Oconee National Forest in central Georgia. The 390' elevation floodplain site stretches for about two miles along the eastern bank of the 250' wide Ocmulgee River. At the southern end the floodplain is only about 150 yards wide and the northern end shows signs of disturbance in the past few decades, but the central part of the tract includes a third of a mile broad swath of mature bottomland forest. No trenches or other artificial landforms indicate past agricultural disturbance, so the site was likely cleared for timber 75 to 100 years ago. Elevation differences of only a few feet within the floodplain produce forest of distinctly different composition. The highest ground occurs near the river as natural levees. These areas probably contain the most coarse-grained, and well-drained soil. Bitternut hickory, black walnut, and tuliptree make up the canopy under these conditions. Florida maple dominates the midstory, and silverbell, American holly and mock-orange (Philadelphus sp.) fill in the understory. Loblolly pine dominates the extensive, flat, slightly elevated areas within the floodplain with some cherrybark oak scattered in the canopy. Shurmad oak, shagbark hickory, swamp chestnut oak, and sweetgum often grow where these areas transition into lower forest. The understory in this area is largely open with only scattered American hornbeam and a few dogwoods and hophornbeam. Puddles and water a few inches deep still covered much of the lower floodplain. A mixture of oaks and a few hickories form a high continuous canopy over this area. The hickories are primarily water hickory (Carya aquatica) and confined to the lowest areas. Overcup oak or willow oak, the most common species in the lower floodplain, grow next to the hickories. Cherrybark oak commonly inhabits slightly higher ground with other willow oaks. American hornbeam makes up most of the understory, but possumhaw also occurs in the lower areas. River bank and tributary streams also provide slightly different habitat. The light trunks of sycamore and river birch periodically project out of the riverbank over the brown water. Sycamore is more common along to small tributaries within floodplain, but completely absent from the rest of the floodplain. Above the floodplain, narrow corridors of flat land snake along the tributaries between gentle south-facing slopes and higher, steep, north-facing slopes. Many of the floodplain species plus red maple grow in the flats. White oak, shagbark hickory, pignut hickory and other hardwoods dominate on the north facing slopes. A few chinquapin oaks and oakleaf hydrangea also grew on the lower part of a north-facing slope. Species Cbh Height Beech, American 12'7" NA Bumelia, Gum 1'4" 27.3' Bumelia, Gum 1'8" 30.2' Cottonwood, Eastern 8'5" 124.3' Hickory, Bitternut 9'5" 105.9' Hickory, Bitternut 9'9" 112.1' Hickory, Bitternut* 6'11" 133.1' Hickory, Shagbark 8'6" 123.7' Hickory, Shagbark* 6'1" 129.3' Hickory, Water 11'0" 120.2' Hickory, Water 10'11" 124.8' Hickory, Water 7'11" 128.1' Oak, Cherrybark 9'11" 137.8' Oak, Northern Red* 7'10" 126.8' Oak, Overcup 9'4.5" 113.1' Oak, Overcup 12'7" 122.0' Oak, Shumard 11'1" 124.5' Oak, Shumard* 9'9" 136.2' Oak, Water 6'8.5" 123.5' Oak, White* 7'4" 122.6' Oak, White* 6'10" 126.6' Oak, Willow 9'6" 130.1' Oak, Willow 10'7.5" 131.4' Oak, Willow 11'2" 133.7' Oak, Willow 15'9" 144.9' Pine, Loblolly 9'1" 130.1' Pine, Loblolly 7'10" 130.3' Pine, Loblolly* 7'9" 130.6' Pine, Loblolly 4'11" 130.8' Pine, Loblolly* 6'8" 137.5' Redbud, Eastern 1'10" 53.1' Sugarberry 9'4" 115.0' Sweetgum* NA 128.2' Sweetgum 7'11" 130.8' Sycamore 7'0" 121.6' Sycamore 8'5" 126.3' Tuliptree 11'4" 128.4' Willow, Black 3'1" 76.0' Rucker Index 133.3' Willow Oak 144.9' Cherrybark Oak 137.8' Loblolly Pine* 137.5' Shumard Oak* 136.2' Bitternut Hickory* 133.1' Sweetgum 130.8' Shagbark Hickory* 129.3' Tuliptree 128.4' Water Hickory 128.1' Northern Red Oak* 126.8' *Denotes tree growing in a ravine. All other trees grow in the floodplain. Most heights were collected using the rangefinder at a steep angle measured with a clinometer and adding a directly measured height between eye level and the base. This method appears to give the best results for broad crowned trees growing on flat ground. The beech has a greatly swollen base. Gum bumelia (Bumelia lanuginosa) is scarce and restricted to the levee. Cottonwood is rare in the area within only two live and one dead individual seen. The bitternut hickory is tied for second tallest known in Georgia. The shagbark hickory is the tallest so far verified in the state, but taller individuals surely exist. ENTS has not previously documented water hickory, overcup oak, or black willow heights in Georgia. The shumard oak is within a foot of the state height record and this measurement is probably more reliable. The water oak slightly eclipses a tree at Rock Creek to be the tallest documented so far in the state. The white oak is the third tallest found so far in the state. Willow oaks approximately 9' cbh x 130' tall are common at the site. The 15'9" x 144.9' individual is likely slightly older than the surrounding forest and is a new eastern height record. The sugarberry is the third tallest known. Jess Riddle   Home