Fossil pollen only clue to early vegetation here

     About 12,000 years ago the last glacier receded from the Chippewa Valley, leaving behind a barren landscape devoid of plant and animal life. No evidence remained of the type of vegetation that occurred in the region prior to the glaciers.
     However, there are several methods used to reconstruct vegetation changes that have taken place since the last glacier. One method is fossil pollen analysis.
     Pollen has several characteristics that make it an ideal fossil. It is resistant to decay, is produced in large quantities, and because it is so small and light, is carried great distances by the wind.

Decomposition slow

     Some pollen grains invariably land in cold, acid waters of bogs or swampy areas where decomposition is very slow or may not occur at all. As the bog fills with organic peat deposits, a new layer of pollen from surrounding vegetation is sandwiched between layers of peat each year. Thus, and annual record is made of the type of pollen that "rained" down on the bog.
     Some pollen records date back almost 12,000 years, or shortly after the last glacier. By removing a core of peat from a bog and examining pollen content, much can be learned about changes in vegetation in surrounding uplands.
     Pollen profiles from a number of bogs in Wisconsin, one in northwestern Chippewa County, have been examined.
     Much of the pollen at the bottom of the Chippewa County bog was from spruce and fir trees. This suggests forests established after the glacier were very much like spruce-fir forests in Canada today.
     In fact, cores from bogs in other parts of the state indicate almost all of Wisconsin was covered by spruce-fir forests.

Warm dry climate

     About 4,000 years ago a very warm and dry climate prevailed. This change in climate is represented by an increase in the amount of oak, pin and grass pollen in the peat core.
     Since that time, and up until the time of settlement, relative amounts of different types of pollen have not changed much in the southern part of the Chippewa Valley. In the northern part of the valley ;the amount of pine pollen has increased somewhat, while the amount of grass pollen decreased.
     Thus, from the time the last glacier left this area until about 1850, the time of settlement, the following changes probably took place:
     A spruce-fir forest became established on the glacial till, but was eventually replaced by hardwoods and pine. About 4,000 years ago oak and pine prevailed in the forests, but large grassy prairies also occurred on the landscape.
     No major changes occurred in the southern part of the Chippewa Valley since that time, although more forests, especially those dominated by pine, developed to the north.
     Writings of early explorers often included descriptions of vegetation they observed on their travels. However, since most of them followed water courses, their descriptions were mostly of somewhat specialized plant communities of river bottoms and river banks.
     Geologists working for the state made a number of surveys in the Chippewa Valley region in the late 1800's. They often reported rather detailed descriptions of vegetation. Also, many county histories were written around the turn of the century and these often included descriptions of vegetation dating back nearly to the time of settlement.

Early descriptions

     Character of the vegetation was described in an early account as:
     "The lands are mostly prairie, slightly rolling and interspersed with an abundance of fine timber. We are located within 15 miles of the inexhaustible pineries, one lying on the Chippewa River, the other on the Eau Claire River."
     Richest source of information on the nature of vegetation at the time of settlement is the original land survey.
     When surveyors established a section or quarter section point, they measured the distance and compass bearing to the nearest tree on each side of the line. This information, along with common names of trees and their diameters, was recorded in fieldbooks.
     If there were no nearby trees, surveyors constructed a mound of earth and sod, and so stated. Every major change in vegetation, rivers, streams, ponds, lakes, caves, windfalls, was noted in their records. Also, at the end of each section line they wrote a brief description of the mile they had just traveled.
     Original General Land Survey records of Eau Claire County have been examined and the result is the map of the vegetation as it appeared in 1850. Differentiation between prairies, oak openings, barrens and forests is made on the map.
     Prairies are defined as areas with less than one tree per acre.
     Oak openings had more than one tree per acre, but less than 50 per cent of the area was shaded by trees.
     The account of original vegetation of Eau Claire County was developed from an interpretation of surveyors' records. In some cases common names used for the species of trees were different from the names in use today.
     Jack pine was called pitch pine, black pine, or spruce pine, depending upon the surveyor. Red pine was called yellow pine, while white pine was simply called pine. Sugar maple was often called sugar, basswood was called lind, and butternut was often called walnut.
     Area mapped as prairie represents the single most extensive type of vegetation in the county at the time of settlement. Of 2,053 points established in the county by surveyors, 888 (44 per cent) were mapped as prairie.
     The greatest expanse of prairie occurred in the central part of the county, south and west of alluvial terraces of the Eau Claire River. Unfortunately, surveyors rarely included any information on herbs present.
     Most section line descriptions simply state "nothing but grass," "rolling prairie," "level prairie" or "first rate prairie."
     A substantial number of section line descriptions indicate much of the area mapped as prairie had various amounts of oak scrubs present. Included in surveyors' notes were descriptions such as "some oak bushes," "considerable oak brush" or "covered with oak brush."

Early grasses on prairies

     Undoubtedly such grasses as big bluestem, little bluestem, Indiangrass and needlegrass; and herbs such as spiderwort, flowering spurge, phlox, goldenrod and blazing star were abundant on these early prairies. These plants still occur in the Eau Claire area, especially along railroad tracks and roadsides.
     Scholars attribute presence of large tracts of prairies in Wisconsin and throughout the Middle West to periodic burning by Indians. Apparently Indians used fires fro driving game in their hunts, for attracting game to the new growth after the fire and other purposes.
     Fire undoubtedly was responsible for the prairies of Eau Claire County. H.A. Towne, and early settler, provides the following description:
     "The low ground was covered at the time by dense poplar thickets through which the prairie fire would run every few years, killing them but leaving the dead young trees still standing until a new fire should sweep the country and find dry timber and consume them."

Offers prairie description

     E.T. Sweet, an early state geologist, gives the following description of prairies located northwest of Eau Claire:
     "Analogous to the barrens are areas known as brush prairies and simply prairie. In some of these prairies, young trees are springing up, and bid fair, if undisturbed, to attain the usual size. These are appealed to as examples of prairies returning to forest, since annual fires are no longer permitted to ravage the region.
     So far as these areas are concerned, the appeal seems to be well taken, save that we might, perhaps, justly dissent from the use of the word prairies as applied to them; for there seems to be no evidence that these ever were prairies in the sense of being completely and compactly covered by prairie grass, to the exclusion of all shrubs and stubs of arboreous plants, as in the case of true prairies.
     They rather appear to have originally been open forest areas, which, on account of the character of the soil, were especially subject to dryness, thus to destructive action of annual fires while moister adjoining areas escaped. On the cessation of the destructive agent, they appear to be returning to their normal condition.

Oak openings

     Oak openings occurred primarily in the southern and western parts of the county in association with prairies. A total of 384 (19 percent) of the corner points in the county are mapped as oak opening.
     Major tracts of oak openings occurred along streams, especially Lowe's Creek, Otter Creek and Bridge Creek. Patterns of distribution of oak openings were probably related to reduced frequency and/or severity of fires in these moister regions compared to surrounding uplands.
     Of 12 species of trees recorded by surveyors, most common were burr oak, white oak and black oak. Species of pine, birch, aspen and elm also occurred at some section corners.

The barrens

     Most of the sandy stream benches along the western two-thirds of the Eau Claire River were apparently occupied by a mixture of oak and pine. This is mapped as the oak-pine barrens. The area included 249 (12 percent) corner points.
     The oak-pine barrens generally formed a mosaic of separate stands of oak and pine of various sizes.
     Sweet wrote the following description of the barrens of northwestern Wisconsin:
     "The trees are either scrub-pine or blackjack oak, averaging in diameter about three or four inches and in height not over 15 feet. In some places, as in the sand hills of the barrens, trees are at considerable distances from each other, and in other places little scrub pines, not over two inches in diameter, are so close together as to constitute a nearly impenetrable thicket. On the sides of the barrens, and in low places, quite large groves of Norway pine are frequently found."
     Moses Strong, another early state geologist, described barrens near St. Croix Falls as follows:
     "The timber occupying these tracts is peculiar and does not justify the application of the term barrens. Some portions are covered with scrub pine to the exclusion of all else save underbrush. Most nearly similar are the patches of Norway pine. Other areas are covered with burr, black and even white oak bushes, with occasional trees of these species...There are also areas where white pine occurs"
     Section line descriptions of this area varied considerably and included such entries as "scattering spruce pine," "scattering oak," "scrub oak," "nearly barren," "timber small pine, quite thick," "some small pine on east one half, west one half oak barrens" and "sparse pine timber, undergrowth of jack oak."
     The most common trees listed by the surveyors were jack pine, hills oak, burr oak, white oak and aspen. Red pine, white pine and birch were also quite numerous in places.

Major differences noted

     The area mapped as pine barrens is continuous with the oak-pine barrens and occurs along the Eau Claire River in the eastern part of the county. Major difference between these two vegetation types is the increase in relative proportions of pine over oak.
     Jack pine was the predominant species, although there were large numbers of red pine and, in some places, white pine. Red oak, white oak, aspen and birch also occurred as did occasional individuals of ask, red maple, elm and black cherry.
    Section line descriptions of pine barrens by surveyors included such entries as "scattering pine," "pine barrens," "timber black and yellow pine" and "white and yellow pine, first rate."
     After a forest fire, large numbers of pine seedlings often become established and an even-age stand of pine may develop and persist for hundreds of years. Red oak, white oak and red maple occurred throughout the forest and sugar maple and basswood were quite numerous in some parts of the northeastern corner of Eau Claire County.
     Other species of trees found in the forest were aspen, birch, elm, ash, hop hornbeam, butternut and black cherry.
     The character of the forest was that of a dense stand with exception of rather numerous windfalls. Forty-six of the 414 survey corner points (11 percent), were located in windfalls. A characteristic descriptive entry in the field notes is:
     "16:00. Leave swamp and enter windfall, bears N and S; 40:00. Set post for 1/4 sec., corner W Pine 16"S 89E 592 links, no other tree near; 55:0. Leave windfall, bears N and S."
     Some characteristic section line descriptions of these windfalls included:
     "Timber dead pine," "timber mostly dead and fallen" and "undergrowth in windfall brush and briars."
     White pine was the most frequently used witness tree in these windfalls, and soil types were mostly wet alluvial. Tip-up mounds left by uprooted trees are still in evidence in some places.

Windstorms another catastrophe

     Forests, although escaping destruction by fire, were subject to another catastrophe, windstorms. About 11 percent of the corner points in forests of Eau Claire County were recorded as being in windfalls at the time of settlement.
     These occurred primarily in white pine stands which had developed on poorly drained soil.
     The relationship between vegetation as it existed in about 1850 and contemporary land use patterns is quite apparent. Regions previously prairie and oak openings are now predominantly farmland. Oak-pine and pine barrens, as well as some of the forests, are presently county-owned forest.
     The major portion of vegetation of Eau Claire County at the time of settlement was open, or dominated by species of trees of low shade tolerance.
     This indicates the importance of fire, and to a lesser extent, windstorms, on development of vegetation prior to settlement by white men.
     With settlement came cessation of prairie fires and cutting of pineries.
     This caused forests to spring up on what was once prairie and oak opening, and the forests to change in composition from those dominated by white and red pine to dominance by oak and aspen.
     Vegetation of the barrens has shown the least amount of change in composition, although the character of this vegetation type has changed to more closed form.

--William Barns, UW-EC Biology Dept.

Extracted from the Eau Claire Leader Telegram
Special Publication, Our Story 'The Chippewa Valley and Beyond', published 1976
Used with permission.