Table Lu03: Descriptions of land type association (LTAs) groups as well as a condensed (1 of 6) description of the 15 LTAs within the North Fork Watershed
Table Lu03. Descriptions of land type association (LTAs) groups as well as a condensed (1 of 6) description of the 15 LTAs within the North Fork Watershed. Descriptions are quoted in part or whole from MDC (1997).
Oak Woodland Dissected Plains and Hills Group
Landform: Distinguished by rolling to moderately dissected topography. Local relief is 75-150 feet. Very broad, flat ridges give way to gentle side slopes and broad stream valleys. Karst plains with frequent shallow sinkhole depressions are common. Broad stream valleys most often occupied by losing streams, however occasional seeps do occur and can spread across substantial portions of a valley.
Geology: Commonly underlain by Jefferson City-Cotter dolomites with a common loess cap. Some minor areas underlain by Roubidoux sandtones.
Soils: Soils are variable, ranging from shallow to bedrock and fragipan soils, to deep, cherty and well-drained loams. Tree root growth is often restricted by bedrock, pans or clay mineralogy, especially high in the landscape.
Historic Vegetation: Open woodlands with occasional prairie and savanna openings was the principal vegetation type. Post oak and black oak were the principal woodland tree species. Historic fire likely played an important role in maintaining an open canopy, sparse understory and a dense herbaceous ground flora. More dissected lands likely contained mixed oak woodland and forest. Unique sinkhole ponds, wet prairies and seeps were scattered in the broad valleys and depressions.
Current Conditions: Currently a mosaic of fescue pasture (35-65% cover) and dense, often grazed oak forest. The transition from open grassland to closed forest is abrupt and the patch work blocky. Very few native grasslands or savannas are known, and the dense second growth woodlands have very little ground flora. Most sinkoles, wet prairies and seeps have been drained and heavily grazed. Many roads, towns, cities and businesses are located in these LTAs.
- Ava Oak Woodland Dissected Plain: Gentle Dissected Plains in headwaters of Beaver Creek.
- Gainville Oak Woodland Hills: Dissecte Hills in upper reaches of Little North Fork Drainage. This LTA is more dissected and timbered than others in group.
- Howell-Oregon Oak Woodland Dissected Plain: Dissected Plain in southern Howell and Oregon Counties. More dissection, better soils, and more existing timber than most other LTAs in this group.
- Romance Oak Woodland Dissected Plain: Small dissected plain on divide between Little North Fork and Bryant Creek.
- Upper Gasconade Oak Woodland Dissected Plain: Broad divide encompassing the headwaters of the Big Piney and Gasconade River Watersheds.
- Vanzant Oak Woodland Dissected Plain: Divide between North Fork River and Bryant Creek.
Oak Savanna/Woodland Plains Group
Landform: Very broad flat uplands slope gently to very broad flat drains or solution (karst) depressions. Local relief is less than 75 feet.
Geology: Underlain mainly by Jefferson City-Cotter dolomites with a common loess cap. Minor areas of the Roubidoux formation occur. Headwater streams are nearly all losing.
Soils: Fragipan soils or soils with shallow restrictive clays or bedrock are common, inhibiting tree root growth.
Historic Vegetation: Oak savannas and woodlands with common prairie openings were the predominant historic vegetation. While few prairies were named by original land surveyors, early descriptions portray an open, "oak prairie" landscape. Fire likely played a principal role in maintaining a grassland-open woodland structure. Some sinkhole depressions would have had unique ponds and seeps.
Current Conditions: The largest blocks and greatest acres of grassland (45-65% cover) are currently associated with these LTAs; grasslands are mainly fescue pasture. Less than 40% of these LTAs are timbered, mainly in dense, second growth oak forest (post and black oaks) with common grazing pressure. Very few quality native prairies, savannas, woodlands, sinkhole ponds or seeps are known. Many of the regions roads, towns, and businesses are associated with these LTAs.
- West Plains Oak Savanna/Woodland Plain: Very extensive, flat upland in the center of Howell County.
- Cabool-Mt. Grove Oak Savanna/Woodland Plain: Two narrow, high, flat divides between the Upper Gasconade and North Fork Drainages.
Oak-Pine Woodland Forest Hills Group
Landform: Mainly broad ridges, moderately sloping (<25%) side slopes, and relatively broad entrenched valleys with local relief between 150-250 feet. Steeper, more dissected areas occur locally near larger stream valleys. Sinkhole depressions are common on broader ridges. Stream valleys vary somewhat from broad and rather shallow, to more deeply entrenched, narrow, and meandering. Many losing streams occur in valleys distant from the main rivers. Cliffs, caves and springs are commonly associated with larger, perennial stream valleys.
Geology: Roubidoux cherty sandstones and dolomites occupy most ridges and upper side slopes, while lower side slopes, especially near major streams are in cherty upper Gasconade dolomite materials.
Soils: Soils are mainly deep, highly weathered and very cherty silt loams with clays at varying depth. Broad ridges may have a loess cap with occasional fragipans, and shallow soils with dolomite bedrock near the surface occur frequently on steeper, exposed slopes.
Historic Vegetation: Pine and mixed oak-pine woodland originally dominated the more gently sloping upland surface associated with the Roubidoux Formation. Early descriptions portray an open, grassy and shrubby understory in these woodlands, a condition related to the prevalence of fire in the historic landscape. Oak and oak-pine forest occupied lower slopes and more dissected, hilly parts of these landscapes, as well as the wider and more well-drained bottom. Bottoms with richer alluvial soils and more abundant water likely were forested in mixed hardwood timber. Dolomite glade and open savanna/woodland complexes were common on exposed slopes with shallow soils. Sinkhole ponds and fens were dotted occasionally throughout.
Current Conditions: Mainly forested in second growth oak and oak-pine forests; forest cover ranges from sixty to over 80%. Most forests are rather dense, near even-age second growth, with very little woodland ground flora. The occurrence of shortleaf pine in these forests has diminished from its original extent, today having only 20-30% of the forest cover containing a substantial component (>25%) of pine. Even age stands dominated by scarlet, black, and white oak are common, oak die back is a common problem. Much of the existing timber land is associated with public land ownership. Cleared pasture lands occupy many of the broad stream valleys and highest, flattest ridges. Many glades and woodlands suffer from woody encroachment, and sinkhole ponds and fens have been drained or severely overgrazed. An exceptional proportion of state-listed species sites are associated with the streams, springs, caves, cliffs, fens, and sinkhole ponds in this group.
- Bryant Creek Oak-Pine Woodland Forest Hills: Includes most of the valley. This LTA has the lowest relief, forest cover, and pine component in group.
- North Fork River Oak-Pine Woodland Forest Hills: Include most of valley; exceptional pine component and U.S. Forest Service ownership.
Pine-Oak Woodland Dissected Plains
Landform: Broad, flat to gently rolling plains which give way to moderately dissected and sloping lands associated with the headwaters of major drainages. Valleys are broad and local relief 100-150 feet. Clusters of karst sinkholes are common. Streams are mainly headwater streams with flashy, intermittent flow.
Geology: Underlain by cherty sandstone and dolomite of the Roubidoux Formation with frequent loess deposits on the flatter uplands.
Soils: Soils are formed principally in cherty sandstone and dolomite residuum from the Roubidoux Formation. Soils are mainly deep, cherty, and highly weathered, low base soils. However occasional fragipans and shallow to bedrock soils do occur. Most soils are extremely well drained and droughty.
Historic Vegetation: Originally covered in woodlands of shortleaf pine and mixed pine oak with an open understory of dense grass and shrub ground cover. Post oak woodlands occupied occasional loess covered flats. Unique sinkhole ponds dotted the landscape.
Current Conditions: Over 75% of this group are currently forested in dense, even-age oak and oak-pine forest. Only 20% of these forests have a strong pine component. However, the proportion of forests containing shortleaf pine is the highest in this group. Dense stands of near even age scarlet, black, and post oak occur in the place of pine. Understories are dense, woodland ground flora sparse, and oak die-back common. A substantial component of these forested lands are publicly owned. Approximately 20% of this group is currently pasture, which often occupies the broad valley bottoms or karst plains. Most sinkhole ponds have been drained, dozed or severely overgrazed. Headwater streams are subject to grazing and bank erosion.
- North Fork Pine-Oak Woodland Dissected Plain: Flat to rolling landscape along the eastern edge of the North Fork Hills.
Dolomite Glade/Oak Woodland Knobs
Landform: Prominent dolomite knobs and high extended ridges which, as erosional remnants, rise above the surrounding landscape.
Geology: Jefferson City-Cotter dolomites form the core of this landscape. Knobs often have a cap of cherty Mississippian limestone. The cap often exists as residual, very cherty sediments left from millennia of erosion.
Soils: Soils in the uplands are mainly shallow to bedrock with varying amounts of cherty residual overburden. The thin soils support extensive unique dolomite glade and oak savanna/woodland complexes. Deeper soils are mainly cherty loams formed from the cherty residual limestone and dolomite materials.
Historic Vegetation: Extensive open and thinly wooded areas. Oak woodland and forests were confined to the roughest land and valleys. The extensive open glades and savannas supported numerous unique species, many found only on these habitats in the White River Hills subsection. Fire history studies indicate frequent (3 year fire free interval) fire in these landscapes prior to settlement
Current Conditions: Most of the dolomite glades and woodlands have grown up in thick stands of eastern red cedar and other invaders. In addition, widespread grazing pressure has lowered the diversity of many glade/woodland areas. Efforts to reintroduce fire and eliminate woody species encroachment has had substantial success on a limited number of acres. Caney Mountain C.A. and the Ava District of the Mark Twain National Forest encompass a significant portion of these LTAs.
- Gainesville Dolomite Glade/Oak Woodland Knobs: Encompasses the Gainesville Monadocks, a prominent set of unique knobs. Caney Mountain C.A. occupies a large portion of this LTA.
Oak Woodland Hills and Breaks
Landform: This Group exhibits relatively rough topography with local relief of 150-250 feet. The Upper Swan Creek Breaks represent a more abrupt steep and intricately dissected landscape than the North Fork Hills.
Geology: The Geology of this Group is primarily composed of the Jefferson City-Cotter formations. Scattered dolomite knobs are interspersed through relatively rugged hills. In addition the uplands in Upper Swan Creek frequently have a cap of cherty Mississipian limestone.
Soils: Areas of shallow soils are frequent with deeper cherty loam soils above and below them.
Historic Vegetation: Likely, common dolomite glade and cherty savanna/woodland complexes on steep sideslopes. Oak woodland and forest occupied deeper soils, especially along valleys.
Current Conditions: Broader, flat to gently rolling uplands and broad bottoms are currently fescue pasture. This is especially true in the North Fork Hills. Glades and Savannas are extensively overgrown with eastern red cedar and other woody species; and suffer from a history of intense grazing. Forest consists of mainly second growth oak in various mixes. Mainly private ownership.
- Upper Swan Creek Oak Woodland/Forest Breaks: Rugged hills with abrupt breaks into upper Swan Creek Valley.
- North Fork Oak Woodland/Forest Hills: More typically rolling to dissected hills landscape with common glade/woodland complexes.