Popular Science Monthly/Volume 80/March 1912/Glimpses of the Great American Desert
|GLIMPSES OF THE GREAT AMERICAN DESERT|
By Professor RAYMOND J. POOL
THE UNIVERSITY OF NEBRASKA
THOUSANDS of years ago when the forces of nature were at work shifting and gradually shaping the features of the Great Plains, large areas of Tertiary sandstones were exposed in Dakota, Wyoming, Nebraska, Kansas and other parts of the western plains. As topographic features were slowly evolved, these sandstones, being young and soft, readily yielded to the eroding action of the elements and were reduced to light, fine-grained sand. In addition to this sand formed in situ probably considerable amounts of other sands were washed or blown into the region from farther west. Great quantities of the sand thus formed were caught up by the wind and heaped into mounds that finally grew to be large sand dunes extending in long ranges and ridges for many miles over the sandstone beds. Thus were the Sand Hills of the Great American Desert formed in the days preceding the advent of plants or men into the regions now characterized by the billowy hills covered with the bunch-grasses and their associates.
The Sand Hill landscape in these early days was probably a restless maze of wandering sand dunes. In later years certain plants crept in from the surrounding plains, only to be uprooted and blown away. After many such invasions some individuals finally succeeded in maintaining a foothold in the more protected portions of the hills. Notwithstanding the terrible conditions imposed by an arid climate and a continually shifting soil, vegetation continued to spread to other areas from these primary centers of establishment.Some time after the Sand Hill flora had gained a lasting hold upon the dunes and the greenish hue of vegetation had spread over the great expanse of hills, enormous herds of bison came charging into the region
in quest of forage. The vegetation was closely grazed and tramped into the unstable soil. And then the red man came, who killed the bison for food, clothing and for many other useful purposes. He sought to improve the range for the wild beast and for his own stock by burning the grass at certain seasons of the year. In this way a third and still greater menace was forced upon the plants that were struggling so hard to cover the Sand Hills with a permanent mantle of vegetation.
The Sand Hill region of Nebraska is one of the largest and best known portions of the sand hills of the Great Plains. In. our state the main body of Sand Hills is oblong in shape with irregular margins. This region lies north and west of the central portion of the state. On the northern edge of the region there are numerous deep canyons with steep, more or less wooded sides. A few more or less isolated areas of Sand Hills occur outside this great main region both north and south of the Platte. A glance at the accompanying map will show the location and comparative size of the main region and the outlying areas of sand hills.
The Sand Hills of Nebraska cover an area of more than 18,000 square miles, almost one fourth of the total area of the state. This is about equal to the combined areas of New Hampshire and Vermont. The hills are all round-topped or conical and smooth, clearly showing that they had been shaped by the wind long before their invasion by plants. There are many depressions between the hills, many of which assume the proportions of valleys more than a mile in width and sometimes many miles in length. From these well-developed valleys the low places decrease in both width and length until they are mere narrow, saucer-shaped basins or "pockets" a few hundred yards across. The well-pronounced valleys are, as a rule, about parallel and trend in a general southeast and northwest direction. Such valleys are frequently completely inclosed by ranges of hills and in this way effectively separated from adjacent valleys, though such may not be more than a half mile distant. Sometimes instead of the valleys being separated by a range of round-topped hills this is accomplished by a continuous rounded ridge. The sides of these hills are often very steep, making difficult the direct passage over from one valley to another.
In the regions of widest valleys the ranges of hills often show a succession of higher hills as one passes back from the valley to the highest points on the divide, which may be from 300 to 400 feet above the level of the valley. In the regions characterized by short valleys and basins the general landscape is strikingly different because in such places the hills rise on all sides without any regularity. Low hills, intermediate hills and high hills are all closely associated, with no long separating valleys. The result is a very abruptly rolling surface with rounded or oblong depressions of varying depth, with the rounded or conical dunes above. There are places where this sort of topography stretches in all directions as far as one can see.
As the name implies, the hills are composed of sand. This sand is of a light straw color (not white) composed mostly of fine grained quartz. The purest sand is found in the newest soil areas such as in "blow-outs" or other places where the overlying vegetation has been completely removed by the wind. In many places, notably on the river flats and in the numerous thickets scattered throughout the hills, there is a copious admixture of organic remains and so the surface soil in such places is a rich black sandy loam and is very fertile. But the characteristic soil of the region as a whole is the pure dune sand composed of very fine particles. As to the chemical nature of the sand, the following table shows it to be very high in insoluble mineral matter and very low in soluble organic or inorganic plant-food materials.
Composition of Sand Hill Soil
|Water and organic matter||4.24||0.92|
The following table shows the size of the soil particles in per cent., and the average of three determinations from different stations in the Sand Hills:
Size of Soil Particles
|Size in mm.||2.0-1.0||1.0-0.5||0.50-0.25||0.25-0.10||0.10-0.05||0.05-0.01||0.01-0.005||0.005-0.0001|
|Average of 3 stations||0.02||0.56||6.69||52.24||33.67||1.66||0.38||3.50|
Such a loose sandy soil soaks up moisture very readily, so that after a heavy fall of rain scarcely any water is drained from the surface into the valleys, but all of it goes into the porous soil. Now and then rainstorms of such torrential fierceness occur in the hills that a great quantity of the sand is brought down from high on the hills and carried into the valleys. Such storms are, however, exceptional, since the usual heavier rains of about 1.0-1.5 in. are completely taken up by the sand, with no surface drainage at all.
In connection with the distribution of soil water in the Sand Hills it is interesting to note that, although the surface of the sand is commonly as dry as powder, the sand but a few inches beneath the surface is quite moist. The average of many soil samples taken during July, 1911 (a wet month for that year), in widely isolated stations at a depth of twelve inches, showed the water content to be 3.27 per cent. The Sand Hills rest upon a series of relatively impermeable clays and stratified rocks. These layers of more solid materials crop out from the surface along streams and on the lower slopes of some hills quite remote from the deeper valleys. The soil is always moister upon a slope with these outcrops than in situations where such are absent.
The annual precipitation over the main body of Sand Hills varies from twenty-three inches in the east to about fifteen inches on the western border. April, May and June are usually the wettest months of the year, while the dry season frequently continues from August to March or the first of April. In the central Sand Hills during the month of July, 1911, five and one half inches of rain fell. At the government forest nursery near Halsey (Thomas County) during this month there was scarcely a day that rain did not fall. The showers were usually light, but a few were soaking rains. Hail sometimes accompanies these thunderstorms in such quantity that a great amount of damage is done to gardens, crops and other property.
Most of the precipitation disappears into the soil at once. It is a rare sight, if indeed it ever happens, that any of the streams or lakes of the region show an increase in volume resulting from the run-off from even the heaviest downpour. Because of the general porous nature of the soil the region is characterized by sub-surface drainage. The fluctuations in the ground water from time to time produce differences in the level of the lakes and ponds. During especially wet seasons the level of the lakes may be perceptibly elevated, due in all probability to seepage from the surrounding hills.
The most important stream of the Sand Hills is the Loup River, the three forks of which rise in low swampy flats toward the central portion of the region. Through the Sand Hills portion of its course the Middle Loup has a fall of about eight feet per mile and so develops considerable current which causes its bed and its channel to shift continually. The sand banks are cut and the channel veers from side to side along its course. This tendency culminates in the formation of many "oxbows"
or loops. Some of these loops are most perfect and beautiful as viewed from far up in the hills. The streams of the region are all shallow, the Loup varying from one to six feet in depth with a channel about fifty yards wide. In many places such streams are extremely beautiful with their winding channels of clear swift water and fringes of vegetation.
The Dismal River is an important tributary to the Loup. Heading in the swamp and lake region of Hooker, Grant and McPherson counties, it continues eastward for about seventy-five or eighty miles, and pours into the Loup at Dunning. This river is an especially welcome sight as one suddenly comes upon it hidden in a deep valley (almost a gorge in many places) after a long, slow, hot ride of thirty miles or more over the hills. The Dismal has cut in a number of places a very deep canyon through the hills. Often the sides of this canyon are almost perpendicular, while elsewhere the banks are not so high or steep. Now and then the stream leaps over a ledge of sandstone producing a waterfall a few feet in height which adds to the beauty of the landscape. There are in truth many spots along the Dismal that would make worthy subjects for the landscape painter.
Few would classify Nebraska among the states with lakes, but as a matter of fact there are hundreds of lakes in the state. Many of these lakes are in the Sand Hills, where they usually occur in groups of few to many in various parts of the region. The largest group occurs in Cherry County, with fifty or more lakes. Some of these, such as Hackberry, Dad's, Clear, Willow, Dewey, Red Deer, etc., furnish excellent sport to the fisherman and the hunter. Aquatic vegetation furnishes abundant food for both fish and fowl. The lakes vary from small ponds a hundred yards across to bodies of water a mile or more wide and four to five miles long. From the top of a certain hill in Cherry County more than twenty such lakes may be seen.
There are many people who still think that the Sand Hill region is a plantless waste of wandering dunes. This is far from fact, but nevertheless the vegetation of the region is sparse and there are also many instances of actively moving sands, although by far the greatest portion of the area is effectively protected from wind erosion by the presence of vegetation. Nowhere except in the moister habitats, as in the valleys, do the plants grow densely or close together. On the hills proper the light-colored sand always shows between the individual plants. In places one may cross over areas two hundred yards or more in width and count all of the plants in his path on his fingers.
Notwithstanding the sparseness of the vegetation there are very many species represented in the Sand Hill flora, but in spite of this great number of species that are found over the hills and ridges and in the valleys, the most striking characteristic of Sand Hill vegetation is its great monotony due to the domination of bunch-grasses, which are the controlling elements of the floral covering of the whole region. The bunch-grasses are so named because from each root there arise many straight, wiry stems in close proximity, so that a clump or bundle of fifty to a hundred or more stems are densely crowded together. These bunches occur more or less scattered in a way such that the characteristic tufted nature of the vegetation results, and the numerous smaller species that occur in the intervals are quite effectively concealed.
A continuous association composed of hunch-grasses is the typical vegetation of the whole Sand Hill region. This covers the hills and ridges over thousands of square miles, being absent only from the "blow-outs" and the moister valleys. Once established in the sandy soil the bunch-grasses cope very successfully with the fury of the wind and the shifting sand. However, if fire or over-grazing seriously reduces the bunches in size and vitality, subsequent winds may uproot and carry them away. But on the whole the bunch-grasses are very effective sand binders, and it would be a great calamity indeed if they
were to be removed and nothing substituted. It is due to them more than to any other single type of plants that the vegetation of the hills is enabled to persist. Within the shelter of the bunch-grass association scores of valuable species thrive that in its absence would never have found access to the region.
The bunch-grass par excellence is the little blue stem (Andropogon scoparius), but associated with it are others, such as sand grass (Calamovilfa longifolia), and needle grass (Stipa comata). Andropogon scoparius is the dominant species throughout the region, the other species being present only occasionally. It is the little blue stem that gives the first greenish hue to the sand hill landscape in the spring, and it is the same species that clothes the hills with the rich reddish-purple in the autumn and through the winter. Hall's blue stem (Andropogon hallii), common on the upper slopes of the hills and the tops of ridges, is usually of secondary importance. Its few tall whitish or bluish stems in poorly defined bunches are, however, conspicuous wherever they are found.
Within the bunch-grass association there are a number of secondary types that are quite well defined. But as one views the vegetation of the Sand Hills in a general way these are lost in the great monotony of the bunch-grass association. However, the vegetation and general life conditions of the uplands, the home of the bunch-grasses, are very noticeably different from those characters on the river flats or in the wet valleys. The exposure to both the drying and the mechanical effects of the wind is most keenly felt on the uplands, composed of the hill tops and upper slopes. Sometimes the wind sweeps over the crests of the hills with such terrific force that one can not stand in its path and endure the sting of the sand blast. During a bright day with a high temperature and such a wind, life on the hills is well nigh impossible. During the hottest days of summer the surface sand in such situations is frequently heated to a temperature of 140° F. Such conditions with a low water content of the soil and a high saturation deficit are the factors that plants must meet. One can not but admire the vegetation that possesses the power of successfully resisting such a combination of conditions. That Sand Hill vegetation has been very successful in meeting these conditions is fully attested by a glance at the region as we find it to-day and a comparison with the dismal waste of bare sand dunes that once wandered over this same area.
Aside from the bunch-grasses, the most characteristic plant of the uplands is the dagger weed (Yucca glauca) which often occurs m great abundance on the upper slopes. In certain portions of the region over restricted areas this species really becomes dominant and the bunchgrasses then play only a subordinate part in the floral covering. The dagger weed reaches its best development on the south and west exposures, although it is by no means confined to these slopes. The sand is often blown away from the roots for many inches beneath the rosette of bristling leaves, and yet the plant continues to thrive. Frequently it puts out new shoots from the exposed roots and develops new rosettes of leaves beneath the old.
The so-called "cat steps" formed on steep slopes in the Sand Hills owe their origin to the grazing habits of cattle and very frequently to the presence of dagger weeds. On such slopes the cattle, avoiding the sharp-pointed leaves of the Yucca, follow angling paths which eventually become netted and worn into the sand in such a way as to cover the hillside with a network of trails. Clumps of dagger weed often fill in the more or less diamond shaped meshes of this network. From a distance, such a slope bears a close resemblance to the "cat steps" so commonly seen on steep slopes in the loess region. The origin is, however, very different. One may find in the Sand Hills a great many stages in the development of these netted trails. They are not necessarily always associated with the dagger weed, since they also occur on slopes with bunch-grasses only.
Like the little blue stem, the dagger weed has little value in the region aside from its interesting and important rôle in the life history of the ridges and slopes. Some economic value is attached to it in that it is eaten by cattle to a slight degree. Especially when the plant is in bloom, if the range is rather short, stock frequently strip every juicy flower from the large spike or panicle, sometimes even eating the axis well down among the needle-tipped leaves. I have seen them attack the young capsules when the range is especially short, so that in a closely grazed pasture one seldom finds a single fruit of the species.Besides the bunch-grasses and the dagger weed there are many other species that occur in greater or lesser frequency in the bunch-grass association. The hairlike eragrostis (Eragrostis trichodes) is an important secondary grass of the uplands that frequently shows the bunch-grass habit. So also Indian millet (Oryzopsis cuspidata), and the black grama grass (Bouteloua hirsuta) are quite commonly seen in the intervals between the bunch grasses. In fact there are more than one hundred species of grasses alone in the Sand Hills, many of which are confined to the uplands. Besides the species already mentioned the following are other common associates of the bunch grasses: Annual eriogonum (Eriogonum annuum) which, with its slender, gray flowering stems and conspicuous flat-topped clusters of flowers, occurs as widely
scattered individuals here and there, or may occasionally form rather dense communities; spiderwort (Tradescantia virginica), tufted hymenopappus (Hymenopappus filifolius), purple blazing star (Lacinaria squarrosa), lance-leaved psoralea (Psoralea lanceolata), western thistle (Carduus plattensis), rough sunflower (Helianthus scaberrimus), prickly poppy (Argemone intermedia), long-leaved milk vetch (Phaca longifolia), green milkweed (Acerates viridiflora), switch grass (Panicum virgatum), prairie pink (Lygodesmia juncea), Geyer's spunge (Euphorbia geyeri), yellow evening primrose (Œnothera romhipetala), sweet pea (Lathyrus ornatus), and hairy golden aster (Chrysopsis villosa). All of these plants occur as scattered individuals except the milk vetch and prairie pink, which are often gregarious. They all show striking anatomical characters that doubtless aid in their survival in such dry soils, exposed to such trying climatic conditions.
In addition to the grasses and the common herbaceous associates the vegetation of the upland is rich in species of low shrubs. In many restricted localities these under-shrubs compose the bulk of the vegetation and really rival the bunch-grasses in dominance. Among these low, much branched, woody plants, New Jersey tea (Ceanothus ovatus), Bessey's sand cherry (Prunus Besseyi), poison ivy (Rhus radicans), and the prairie clovers (Kuhnistera purpurea, K. villosa, and K. alba) are the commonest and most widely distributed. All of these plants are dwarfed, much branched shrubs often growing in communities. 'New Jersey tea is found most frequently near the tops of the hills on north facing slopes, where the dense, light green patches from ten to seventy feet across contrast very greatly with the surrounding bunch-grass vegetation. Bessey's sand cherry is one of the most ubiquitous plants of the whole region. It is found in almost every site of the uplands and with its low, short twigs with tufts of glossy green leaves is seen springing from the sand on practically every side of every hill. Very frequently it forms extensive communities. The prairie clovers seldom form well-defined communities, but they occur as more or less scattered individuals, especially on the lower slopes of the hills adjacent to the larger valleys.
The most striking habitats of the uplands are the "blow-outs." Blow-outs are conical or rounded depressions of varying depth and diameter formed by the blowing of the sand and vegetation from certain spots on the upper slopes and crests of the hills. The rim of the more or less conical depression is sometimes almost circular but it is usually irregular with a general circular outline. Since the prevailing winds of the region are from the west, and since "blow-outs" are the direct products of wind action, these peculiar structures are mostly confined to the west sides of the hills. The greatest number occur on the northwest-facing slope, but they range in position from northwest to southwest, depending somewhat upon the shape of the hill concerned and its relation to the adjacent hills. Blow-outs do not occur on all hills, nor does a single hill show more than a single blow-out, as a rule.
On an exposed upper slope when the vegetation becomes broken or seriously depleted from any cause, the wind as it sweeps up the slope catches the sand and carries it over the crest of the hill a few yards farther away and deposits it upon the lee face of the hill. In this way
as more and more sand is carried away and the up-rooted plants are swept on with the gale, the embryonic blow-out comes rapidly into existence. At this early stage it appears as an area of bare sand a few feet or yards across, over which the wind sweeps and continues to eat its way deeper and deeper into the sand. During this early stage the deep seated roots of woody plants frequently appear strewn over the surface of the shallow depressions until the wind has finally eaten its way far below the point of penetration of the deepest rooted plants. At last the whole rounded or conical hill top is blown away and a deep crater is developed in its stead.
The two chief factors that enable the wind to begin this work of destruction are fire and over-grazing. Both factors frequently result in reducing the vegetation to a point below effective wind resistance and as soon as this is done, if the exposure be right, wind erosion begins. Nothing is quite so terrible as a prairie fire in paving the way for shifting sands and the development of blow-outs, since in such cases absolutely everything above the surface is destroyed. And so if cattle are allowed to run for too long a time over a given range the grasses are seriously reduced and the soil is tramped bare of plants for considerable distances, making it very readily possible for the wind to strike at the open sands. The effects of over-grazing are contrasted to a striking degree in the Sand Hills, where a fence separates the over-grazed pasture from the ungrazed range. Such sights have resulted in the enactment of grazing laws which naturally do not in all cases please the cattlemen, but they do usually protect the range and make it more stable.
When the young blow-out is no more than a foot in depth the sand begins to slide into the depression from the sides. This sand is blown away and more continues to slide in, and in this manner the blow-out increases in area as well as in depth. These two processes continue for a number of years until, in many cases, the well-developed crater-form depression is blown out of the hill. Naturally with the increasing depth of the blow-out the direct force of the wind becomes considerably checked by the prominent rim of the crater. But peculiarly enough, as the wind strikes the farther slope of the blow-out a reverse current is developed which strikes beneath the rim and dips into the bottom of the crater. In this way a spiral wind movement is frequently developed and the wind reaches to the very bottom of the blow-out, which may now be fifty or more feet below the rim. This grinding action of the wind continues to loosen more sand at the sides, causing it to slip more and more into the bottom, where the wind catches it and hurls it up over the sloping interior surface of the blow-out and out over the rim. This action is quite appropriately called the "sand mill." The action of these spiral currents are conspicuous during rather low winds as well as on very windy days. Such activity is a very important factor in hollowing the blow-outs to the greater depths.
After many years of this sort of growth, blow-outs at the end of their maximum activity become enormous depressions with a rim sometimes 300 to 900 feet in circumference with sides of bare sand sloping inward at an angle of about 30 degrees to the bottom, which may be from 20 to 75 feet or more beneath the rim. In the western portion of the region where blow-outs are formed in rather low hills among the lakes the sand is removed from the interior until the water table is reached.
During the years of greatest blow-out activity plants fail absolutely to gain a foothold and establish themselves in the blow-out because
of the great exposure to wind and shifting sand. The combined action of a high wind, high soil temperature, excessive evaporation, and an unstable soil in the active blow-out, is a condition that plants can not survive. Sooner or later, however, because the blow-out has reached such a depth that the "sand mill" becomes ineffective and the sliding sand fails to reach the bottom, certain plants appear in the bare sand of the blow-out. From this time the terrible physical conditions begin to wane and the vegetation gradually creeps up from the bottom of the blow-out and slowly becomes the master of the situation. The decadence of the blow-out is traced in the development of the vegetation from these first successful invasions until the* whole crater-like depression is claimed by the bunch-grasses and their common neighbors.
The first plants to become established in such places are certain grasses commonly called "blow-out grasses." The most important of these is Redfield's grass (Redfieldia flexuosa) which is almost always the very first pioneer in the reclamation of the blow-out. Redfieldia may be the only plant in such situations for many years. All during this time it is extending its area by undermining and binding the soil with its network of slender rhizomes. From these rhizomes there arise tufts of long, flexuous, narrow leaves gracefully nodding in the gentle breeze or lashing about like so many slender wires in the higher winds. Sometimes in a single windstorm the sand level about these tufts may be reduced two inches or more, but seldom are the plants uprooted. It is to the rhizome habit of propagation that Redfieldia owes its success in thus so completely capturing the blow-out. The later invaders are also provided with this device, which certainly is the key to the whole situation.
After Redfieldia has once taken charge of the habitat other species soon begin to wander over the rim of the blow-out and to invade the area occupied by the first blow-out pioneer. Among the first of these early invaders we must number the spiny blow-out grass (Muhlenlergia pungens), sand grass (Calamovilfa longifolia), and the hair-like eragrostis (EragrosUs trichodes). From the appearance of these grasses the decline of the blow-out is rather rapid. As these various species wander up the steep sides, and the force of the wind striking upon the upper slopes is reduced and the sand held from blowing, other species wander in from the bunch-grass association. If these new plants are properly provided with a rhizome device like that of their predecessors they soon begin to weave themselves into the now conspicuous blow-out association. The plants that most commonly gain entrance soon after the grasses have become well established are prairie pink (Lygodesmia juncea), small-flowered psoralea (Psoralea micrantha), long-leaved milk vetch (Phaca longifolia), and the hairy golden aster (Chrysopsis villosa). Indeed, some of these species may get a start in the declining blow-out almost as soon as Redfieldia.
In this manner the effect of blow-out conditions are finally so far removed that the bunch-grasses enter and take possession of the area so well prepared by the pioneers in the succession. It is almost pathetic to find that Redfieldia, the first plant to appear in the blow-out
Fig. 10. A Square Meter Quadrat in the Blow-out shown in Fig. 9. The bunch grass is now conspicuous with a few tufts of Redfieldia at the right.
and the plant of greatest importance in its reclamation, after struggling against severe physical conditions for so many years is also the first to disappear. It fails in the competition with the later arrivals and is then forced to find other blow-outs in which it may continue its great work. With the development of the bunch-grasses and the resulting competition all of the blow-out grasses disappear, and then with the incoming of the characteristic members of the bunch-grass association, the change from blow-out to hillside is complete. The only indications of the former history of the place are seen in the grassed-over crater which frequently persists as a characteristic form, and perhaps a few straggling clumps of the blow-out grasses lingering in the near vicinity.
On the lower slopes of the hills and in the valleys many new species are encountered as the bunch-grasses of the uplands are left behind. Bather low down on the north-facing slopes one frequently finds conspicuous associations of willows (Salix humilis) and dogwoods (Cornus stolonifera). The prairie shoestring (Amorplia canescens) also gives tone to the lower slopes in many places by its typical lowbranching, ashen-colored plants closely aggregated. Even the taller shoestring (Amorplia fruticosa) occasionally wanders from its usual habitat in the moist valley and is found on north slopes among the willows and dogwoods. The presence of such plants always indicates a higher percentage of soil moisture quite near the surface than is found typically in the bunch-grass association. The explanation of this phenomenon is not hard to find, because such associations and such soil conditions almost always mark an outcrop of clay or other impermeable rock strata which lead the ground water from under the hills in a horizontal direction until it is brought near the surface. If the clay or rock does not actually appear on the surface it is usually found a few feet beneath, so that the effect is practically as has been given. The water is frequently so abundant in such situations that it seeps out and collects in cow tracks and other holes in the more tenacious soil. This results in the development of a soggy soil where one finds such moisture-loving plants as marsh mint (Stachys palustris), Venus's lookingglass (Specularia perfoliata), Solomon's seal (Vagnera stellata), heal all (Prunella vulgaris), long-bracted orchid (Cæloglossum bracteatum), rush (Juncus halticus), liverwort (Marchantia polymorpha), mosses (Bryum sp.), etc. The cow tracks are frequently filled with filamentous algæ and free-swimming animals such as Euglena.
The willow thickets, although quite striking structures on the lower slopes, are still well within the bunch-grass association. But as one gets down into the valleys proper the bunch-grasses, and also many of their associates, are left behind. There are two quite distinct types of valleys in the Sand Hills. The dry valleys are relatively short and narrow and with a good covering of grasses which often form a close sod, but with no standing water. The well-developed sod is a condition that causes the vegetation of the valleys to be quite distinct in appearance from that of the uplands, with the tufted appearance of the bunch grass association. Such dry valleys are very common throughout the southern portion of the Sand Hills. They yield an abundant crop of
fine hay during moist seasons and always afford very fine forage because of the presence of buffalo grass (Bulbilis dactyloides), and grama grass (Bouteloua oligostachya) in considerable quantity. The soil of these valleys is not so sandy as the uplands. This with the water table nearer the surface makes possible the culture of certain agricultural crops, if the proper care is taken to prevent the soil from blowing. When the sod is broken in a dry valley where a considerable area of nearly flat soil is exposed to the wind, the blowing soil frequently prevents the growth of field crops or any other plants.
The flora of the dry valleys is very similar to that of the prairie regions of the state, being especially rich in grasses. The principal widely distributed plants of the dry valley are: switch grass (Panicum virgatum), wheat grass (Agropyrum pseudo-repens), blue joint grass (Calamagrostis canadensis), wild rye grass (Elymus canadensis), red top (Agrostis alba), tickle grass (Agrostis hiemalis), rattlesnake grass (Panicularia americana), and a number of sedges (Carex trichocarpa, C. filiformis, etc.). All of these species are valuable forage plants and they are all included in most of the hay that is put up from the valleys. Besides these economic plants there are many other herbaceous members of the prairie flora that have wandered into the Sand Hills and have found congenial homes in these dry valleys.
The river flats properly belong to the dry valley type, since here we find a soil free from surface water and with all of the above species of plants often growing in profusion. These low flat areas extend from the banks of the river back sometimes several hundred yards to the bases of the hills. These flats or "benches" are well developed along the Middle Loup River. The river winds across the flats in a very irregular course, sometimes cutting close to the hills on one side and then shooting across to the hills on the opposite side of the flat. On these flats and along the bank close to the stream occur the most of the trees of the region. Thickets of plum (Prunus americana), and cherry (Prunus melanocarpa), several acres in extent are common in such places. Green ash (Fraxinus lanceolata), cottonwood (Populus sargentii) and willow (Salix nigra, S. longifolia) also thrive on this soil. In the phim thickets near the river the vegetation often becomes so dense that it is almost impossible to penetrate to the river's edge. The soil in these places is very rich and moist, so that many species of the shade plants of moist rich woodlands find in such thickets very favorable conditions. On the open areas of the river flats buffalo grass and grama grass constitute the best forage known in the Sand Hills. These low, sod-forming grasses are especially valuable as winter forage.
Wet valleys are very common in the northern portion of the Sand Hill region, where the valleys are usually broad and long. The water table is near the surface in these valleys, so that the soil in many places is very wet and swampy. There are in this portion of the hills many gradations from the moderately dry hay valley through wet meadow valleys to valleys with large ponds or lakes. Hundreds of lakes occur in such situations throughout the northern half of the Sand Hill region. There have been two general kinds of wet meadows distinguished. The rush-meadow type is characterized by the presence of a number of rushes (Juncus tenuis and J. nodosus), and bulrush (Scirpus atrovirens and S. americanus). With these occur a few moisture-loving grasses, such as lowland rattlesnake grass (Panicularia nervata) and whorl grass (Catabrosa aquatica). In the wet valleys along the Loup River and inwet places on the river flats a second type of wet meadow is seen in the fern meadow. Shield fern (Dryopteris thelypteris) and the sensitive fern (Onoclea sensibilis) often occur in great quantities in such places with a mixture of willow herb (Epilobium lineare), St. John's wort (Hypericum virginicum), goose grass (Galium trifidum) and marsh bellflower (Campanula aparinoides). Frequently the ferns are so dense as to cause considerable difficulty in walking through this type of wet meadow.
There are two kinds of lakes in the Sand Hills, depending upon the amount of dissolved substances in the water, alkali lakes and fresh water lakes. It has been found that the alkalinity of the lakes varies between rather great extremes, even the freshest of the fresh-water lakes being somewhat saline. Whatever may be the cause of this gradient in alkalinity, it is an obvious fact that the degree of alkalinity exerts a very powerful influence upon the vegetation. Studies are now in progress that will probably throw considerable light upon the power of certain species of plants and animals to adjust themselves to this varying chemical relation. In many of the more strongly saline waters scarcely any vegetation appears, although the beach may be well clothed with rushes, sedges and salt-grasses. Frequently even the beach, many feet back from the water's edge, is so thoroughly impregnated with salts that they crystallize and form a white crust over the surface. This results in an absolutely barren zone. Back of that portion of the beach washed by the waves the salt-enduring plants develop very copiously. The saltgrass (Distichlis spicata) is usually controlling in such places where the low plants develop a very close tenacious sod. Beyond the belt of saltgrasses the taller stems of other grasses, sedges and rushes make up another distinct zone which may completely encircle the pond or lake. These plants are very dark green, so that the belts of vegetation about the saline lakes stand in marked contrast to the duller tones of the surrounding hills. Still farther back beyond the zone of tall plants the shore vegetation of the saline lake passes either abruptly or gradually into the typical wet meadow vegetation.
The appearance of the fresh-water lakes is quite different. First of all there is usually a wealth of submerged or half-submerged plants. Some of these lakes are literally filled with great masses of pondweeds (Potamogeton, several species), and the water milfoil (Myriophyllum spicatum). The bottom, in the shallower portions of such lakes, is covered with a carpet of stonewort (Chara fœtida, etc.), while the stems of the submerged flowering plants are richly coated with algae of many kinds. In late summer certain of these algæ become broken away from their substrata and float about on the surface of the water. During high winds at this time great quantities of these, such as the net sack (Clathrocystis æruginosa), are washed on the beach in yellow green splashes. So there are many very interesting animals in the freshwater lakes, a sponge being one of the common forms.
The white, encrusted beach is absent from the fresh-water lakes, as also are the belts of salt-enduring plants. The commonest marginal plant here is the great bulrush (Scirpus lacustris). Frequently this is the only plant between the bunch-grass association of the hills and the open water of the lake. Sometimes other species such as cat tail (Typha latifolia), and the giant reed grass (Phragmites phragmites) occur in mixture with the bulrush, or these may now and then form separate belts. Wild rice grass (Zizania aquatica) is a common marginal or shallow-water inhabitant of many of the lakes. This plant is about as tall as the bulrush, but because of its leafy stems it often forms much denser stands in the shallow water. When the seed is ripe every bed of wild rice is a Mecca for thousands of water fowl that live in the vicinity of the lakes. Wild ducks become so thick at times in these rich feeding grounds that the noise they make reminds one of an over-stocked barnyard.
The lakes range in size from small ponds to bodies of water one and one half miles wide by five miles long. They vary in depth from four feet to probably about twenty-five feet. In many of the fresh water lakes the vegetation is encroaching upon the water, so that in time all of the lakes will have disappeared and wet meadows remain. The wet meadows of to-day show this sort of an origin very plainly. Many stages in lake eradication by invading vegetation may be seen in these lake regions. Some lakes are quite free from submerged aquatic plants; others quite free from bulrushes or wild rice; others show belts of these plants about the shore; in others the bulrushes have begun to wander
and perhaps the stockman now mows his hay where once was open water.
The soil and climatic conditions over the Sand Hills as a whole are such as to fit this region in a peculiar manner for the grazing of immense herds of cattle. It is from the pursuit of this great industry that the region must always furnish its greatest returns. Thousands of cattle are annually shipped to the eastern markets from the Sand Hills. It is truly amazing to the "newcomer" to see how well the stock does upon what seems to be very meager forage. But with a well-kept range for the summer and plenty of hay for the winter the cattleman realizes a neat return from his labors. Those inhabitants who are so fortunate as to possess fertile valley land in addition to their upland range have made considerable progress along agricultural lines. The soil in many valleys is sufficiently fertile for the production of almost all of the common field and garden crops. Naturally because of the low acreage of agricultural land this industry will never reach great proportions. Alfalfa is destined to become the most important single crop in the Sand Hills. There are already many very good fields of this valuable plant. It is especially fitted to the soil conditions of many valleys, and when once established it resists the fury of the wind in a very encouraging manner. The success that has already been obtained by the early sowings should encourage other settlers to try it out very carefully.
Enormous crops of garden vegetables may be obtained from the river flats if the gardens are so situated that the land may be irrigated from the river-—and this is possible in a great many places. There are hundreds of acres on flats along the Loup River that could be made to yield high returns from truck crops. A small irrigation plant would cost but little, and the luxury of fresh vegetables would gladden the whole life of many a Sand Hill housewife who too often "digs" or "pulls" all of her garden truck from cans.
Much has been said and written about the possibility of covering the Sand Hills with trees. About ten years ago the U. S. Department of Agriculture, acting upon a suggestion from Professor Charles E. Bessey, made a preliminary examination of the region to determine if the conditions warranted an attempt at forestation. The examination resulted in the setting aside of about 80,000 acres in the worst portion of the hills between the Middle Loup and Dismal rivers as a national forest. The flats along the Loup afforded very favorable sites for the forest nursery, and, since it was thought best to raise the stock in the hills, a permanent station was established on the south side of the Loup about two miles west of Halsey in Thomas County.
In the spring of 1903 small jack pines were imported from Minnesota and these were set out on the hills. During this summer the forest nursery was started and from that time the Forest Service has continued to raise its own stock in its own nursery and every spring to plant
thousands of trees upon the hills. Naturally there have been mistakes and failures, but after almost a decade of active operations on the Dismal River National Forest one can not but marvel at the results obtained, if he is at all familiar with the extreme natural conditions that the government's experts have attempted to meet. The pine trees that were planted in 1903 are now about twelve feet in height and four inches in diameter. The bunch-grasses have been shaded out and a fine carpet of pine needles is beginning to accumulate beneath the green crowns of this young Sand Hill forest. So also, as I was able to demonstrate during the past summer, the temperature of air and soil, the humidity and evaporation, and the movements of the air in the vicinity of this plantation have been profoundly modified in comparison to those conditions in the bunch-grass association that completely surrounds these plantations. It is a most interesting and significant fact that the trees have adjusted themselves more readily to the fury of the wind on the hilltops and even in the blow-outs than to the struggle with other vegetation in the moister and more protected situations. Mr. Pierce, the supervisor of the Nebraska National Forest, told me in October that eighty per cent, of the trees planted in 1911 had passed through the summer drought and were making a brave effort to become permanent fixtures in the Sand Hill landscape.
The forest nursery established in 1903 has been enlarged from time to time until now it covers about five acres. When all of the seed beds are in use the nursery can care for about four million seedlings and two million transplants. The care of the delicate seedlings requires a great amount of skill and a large force of men in order that they may be kept free from disease and develop perfectly for the planting on the hills.
While it will be many years in the future before any return will be realized from this enormous experiment of the government's, yet the success of the first decade certainly warrants the continuation of the experiment. It is hoped that at some distant time acres of flourishing pine trees will grace many of the hills now so completely dominated by the bunch-grass.
The people of the Sand Hills are a hale and hardy lot. Their life is a rather hard one, even if they take advantage of every comfort possible for them. Many of them were lured by the roseate stories of the early "boomers" and came to the region from the east years ago. They found that the glowing tales of the wealth of the region were mostly florid falsehoods and that they were in a strange land whose productivity was not at all apparent and the rigors of whose climate were at times most severe. Many of these early homesteaders used up all of their capital in getting into the Sand Hills. Once there their disappointment was keen, but they could not return. They settled on the one hundred-and-sixty-acre homestead, and during the first winter lived in a miserable, unhomelike dugout. In such a condition, poorly clad, without coal or other fuel in quantity, they braved that first terrible winter with its icy blizzards, the spring coming barely in time to save
them from an agonizing death. The next summer perhaps they built a small sod house into which were moved the few belongings, and then they began to map out plans for their future existence. There were neighbors in equally straitened circumstances, but after a while it was found possible to buy a few cattle and in this way a permanent livelihood was assured, and the foundations were laid for what is now one of the most important industries of the state.
The population of the Sand Hills is widely scattered. One may ride for twenty or thirty miles in almost any part of the hills and not see more than one or two houses, and frequently in such a ride he may not see a single home or meet a single person. The lack of human associates together with the monotony of the landscape and the slow routine of the lonesome day, the parching winds of summer, the call of the range, and the crimping blasts of winter, has left a telling imprint upon the homesteader and has made him a grizzled, fearless man. Far from the influence of the laws and the morals of civilization, he constructed his own statutes and his own code of morals. There were few entries here, but woe to him of the hills who lived not the life of an open book. "A square deal for all" was the motto that the knights of this grassy kingdom wrote across their breasts. If a horse disappeared from the corral a hurried call was sent forth and a small mounted committee was soon scouring the hills. If the wrong man was found riding away astride the missing animal, he was jerked down, tried before this quickly constructed bunch-grass court, found guilty of horse stealing and was speedily strung up to a tree with a lariat rope, long before a single juryman could be summoned in a region possessed of a "higher standard of
ethics and a solemn regard for the law." Such was justice on the range, especially in the earlier days. Even in this late day the dove of peace does not nest in all the nooks of this great sand-hill domain. There is romance and chivalry of the real western sort in abundance. Only a few weeks ago four stalwart sons of the hills were sent to the state prison for life because of a deed that they thought was merely chivalrous. They went to the ranch house of a neighbor one night, took him from his bed, threw a rope over his head and pulled him up to a telephone pole. They had not intended to take the man's life, but simply sought to intimidate him and cause him to leave the country. He had made certain threats unbecoming to an inhabitant of the hills. He was allowed to dangle at the end of the lariat from the telephone pole too long, and as a consequence the four young men are in prison for the rest of their days.
From these statements the reader must not infer that life in the Sand Hills is dangerous or even uncongenial because of man's relation to his fellows. Naturally these people have individual rights which they will protect with their lives, but to one who "lives in the open," no truer or more loyal friend can be found than in these rough men of the hills. Frugal, but hospitable to the extreme, they take great pleasure in the entertainment, in their humble way, of strangers who may chance among them.Many of the homesteaders in this region after struggling along for a number of years, often facing death through cold or starvation, were compelled to relinquish their claims and leave the hills. So to-day one may find in many places the old dilapidated "soddy" and the scrubby, straggling timber claims of those who gave up the fight. On the other hand, many of those who managed to stay in the region have prospered. The sod shanty was for many years the characteristic habitation of the homesteader's family. This home was added to from time to time until a rather low, three-or four-roomed house of sod with plastered walls afforded much more comfort than the old conditions. At first the roof was also made of sod, but in later years the board or tar-paper roof has been substituted for the leaky sod. Those who have gone into the hills in the past few years and have taken claims under the Kincaid act have commonly built shacks of rough boards. Many of the older residents of the Sand Hills have lived for a number of years in very comfortable frame houses with most of the conveniences of the common farm house. Even the cement block has invaded the hills, and now there are numerous ranches with cement-block homes and round about the many other well-constructed buildings of the up-to-date ranch. Thus the development of the civilization and the architecture of the Sand Hills has passed through a number of periods in many ways as interesting and as remarkable as the evolution of the landscape and the vegetation of this great pasture domain.
- From a series of analyses by Dr. Samuel Avery, 1905.
- From Professor E. H. Barbour, Nebr. Geol. Survey, Vol. 1, 1903.
- Data from official records of U. S. Forest Service at Halsey, Nebr., for last seven years.
- Pound and Clements: "Phytogeography of Nebraska," 1898.
- Pound and Clements.