Bog Forest Research Articles

Relationship of Availability of Phosphorus and Cations to Forest Succession and Bog Formation in Interior Alaska

Concentrations of P, K. Ca. Mg, Mn, and Zn in black spruce foliage were examined in relation to forest succession on north slopes in interior Alaska. decline in levels of P and K in the foliage appear to be deficient on sphagnum soils. Mg levels show a slight decrease, but do not fall below deficiency status even on deeper sphagnum soils. Ca, Mn, and Zn show no relationship to forest succession and are at adequate levels on all stages. Concentrations of available phosphorus and exchangeable cations in the soils show no differences between soils corresponding to those found in nutrient levels in the foliage. However, total quantities of P, K. and Mg in available and exchangeable forms are consistently lower in sphagnum soils. Also, the depth distribution of these nutrients on a volume basis differs among soils: in sphagnums they are located at deeper depths, while on mineral soils they are concentreted in surface layers. this distribution difference and the incrasing coldness of the soil as moss accumulates appear to be sufficient to reduce the availability of these nutrients. Radiocarbon dates showed that 18—28 inches (41—71 cm) of sphagnum peat, weighing 270,000—510,000 kg/ha, had accumulated in less than 185 years. The average annuual increase of 1,500—2,800 kg/ha indicates that, in spite of low growth of trees on sphagnum soils, total productivity in dry weight is appreciable.

A Floristic Study of Forests and Bog Vegetation, Northwestern Minnesota.

Single vegetation plots in forests and bogs in the deciduous and coniferous-hardwood formation in northwestern Minnesota were studied according to the field methods of the Zurich-Montpellier system. Plots and species were arranged so that the greatest coincidence of occurrences was obtained. Species that show approximately similar amplitudes were united in sociological groups. Plant communities typified by these groups were placed in a hierarchy. The plant communities appear to intergrade but are not completely continuous. Definite concentrations of occurrences remain present in the ordination. Fourteen main types of vegetation are recognized. Their relations to the environment are discussed, and their relations to vegetation in other regions are indicated. Thirteen main types of vegetation (alliances) are recognized in the Itasca State Park region. Lowland vegetation has been divided into five alliances. In three of them the pathway of lake filling, starting in a eutrophic sedge mat and proceeding towards a mesotropic Picea mariana bog forest, is depicted. The two remaining lowland types represent eutrophic swamp forest of Fraxinus nigra and Ulmus americana on shallow peat or young alluvial soils. Upland forests havebeen divided into three "rich" deciduous types and five "poor" coniferous types.The rich types are represented by Tilia americana forests, Acer saccharum forests, Quercus rubra forests, and Populus tremuloides-Quercus sp. forests, allshowing representatives of the rich flora of the mesic Tilia-Acer forest. The coniferous forest types are represented by Popuus tremuloides-Quercus sp. forests and closely related Pinus resinosa-Pinus banksiana forests, Pinus banksiana forests on sandy outwash soils, and Abies balsamea forests in a young stage of development. Of these types the Pinus banksiana forest is floristically the best defined.

Stevens Pond: A Postglacial Pollen Diagram from a Small Typha Swamp in Northwestern Minnesota, Interpreted from Pollen Indicators and Surface Samples

The pollen assemblages of a core in the coniferhardwood formation in northwestern Minnesota are compared with the floristics of the recent vegetation in the region. Percentage levels of the main tree components have been compared first with those from recent surface samples taken at the same short distance from various types of upland forests and second with the regional values of the pollen rain in this area (McAndrews 1966). To that end all the data were recalculated on the basis of special pollen sums. The regional diagram of Stevens Pond shows basically the same assemblage zones as established by McAndrews but without the late-glacial Picea-Populus assemblage zone. The pollen in the following Pinus-Pteridium assemblage zone has been interpreted as derived from a pine forest. During the midpostglacial expansion of the prairie eastwards the regional vegetation must have been a Quercus savanna, locally with prairie. Corylus reaches relatively high percentages in this zone. Among the prairie elements especially the occurrence of Lilium philadelphicum may be noted. In the next zone the pollen diagram shows a rise of the curves of mesic elements. In spite of this the comparison with recent surface samples indicates a xerophytic Quercus forest rather than a mesophytic deciduous forest. In the following Pinus assemblage zone pine was present along the margin of Stevens Pond and is therefore overrepresented in the diagram. In the uppermost zone the pollen curves show the effect of logging of the forest about 1900. Pollen of cultivated and introduced plants appear in this zone. Many local pollen types were found, on account of local overrepresentation. This made it possible to compare the local Stevens Pond sequence with the composition of recent lowland vegetation types. The pollen sequence was similar to a large extent to the recent pattern of lake filling, starting with a eutrophic vegetation of Typha latifolia and Salix in the prairie period and leading to a Larix forest and then to a mesotrophic Picea mariana forest, the present edaphic climax on peaty soils. There is a delay, however, in the introduction of acidophilous species, the Larix forest being without Sphagnum and Ericaceae. This is explained by assuming an influence of the vegetation of the surrounding slopes upon the local vegetation. About 1900 the bog forest was destroyed by logging operations and replaced by the present Typha latifolia mat.

String Bogs and Other Patterned Organic Terrain Near Seney, Upper Michigan

Treeless string bogs and topographically oriented strips of bog forest have been discovered near Seney, Michigan, lat 46 degrees 15' N, perhaps the southern limit of patterned bogs on the North American continent. Patterned ground has developed through paludification of a sandplain dotted with extinct dunes and sloping about 8 ft/mile. Many peatlands in Michigan, Minnesota, and Wisconsin have similar slopes and exhibit patterning in various degrees. Thus the principles that can explain the patterns and bog—forming processes at Seney may apply to large areas of forested and treeless peatland. Studies should be directed toward the interrelations between vegetation, water chemistry, local geology, peatland topography, peat hydrology, peat accumulation, and physical geomorphic processes.

Early Summer Activities of Porcupines as Determined by Radio-Positioning Techniques

well as on preference of tree species and/ or ground level shelters as daytime resting places. In addition, observations were made on the influence of mosquitoes on activity and on foods taken. This study was conducted at the Forest Research Center of the University of Minnesota near Cloquet, Minnesota from May 26 to July 16, 1960. The 3,300-acre area lies in a glacial outwash plain that is much interrupted by eskers and basins, the latter now in the bog-forest stage of succession. Upland tree cover consists of a variety of conifer-hardwood forests (Allison and Brown, 1946; Burcalow and Marshall, 1958). In both the upland and bog forests there is a heavy undergrowth of brush, herbaceous plants, and ferns (Magnus, 1949). Details on the use of the miniature 50-g radio transmitters having a signal range of approximately 1.5 miles are described in a preliminary report (Marshall, 1960). A unit was fastened on the back of each of 2 adult female porcupines by means of a modified dog harness and on the back of an immature female, the young of one of the adults, by means of a homemade buckskin harness. The location of the animals was determined at dawn, midday, and dusk by means of a 14-lb portable radio signal-locator equipped with directional antenna. Most records re-

BRYOPHYTES FROM THE EDMONTON REGION, ALBERTA

For an area in south-central Alberta, 159 bryophytic taxa are reported. Approximately, two-thirds of these are new records for the area and 19 are apparently new to Alberta. Some of the more significant records for Alberta are Sphagnum robustum, Aloina rigida, Brachythecium acutum, Calliergon trifarium, Leskea obscura, Haplocladium microphyllum, Thuidium philibertii, Entodon cladorrhizans, and E. orthocarpus, the latter a rare species in North America. Ecological notes are included for most of the species. Moss synusiae of wet meadow, wet thicket, Sphagnum bog, bog forest, and marl bog are described and the main hydroseres are indicated.

MARSH AND BOG VEGETATION IN NORTHWESTERN ALBERTA

Swamp, marsh, wet meadow, saline meadow, Drepanocladus bog, and Sphagnum bog are characterized and related aquatic vegetation is described briefly. There is succession from different kinds of swamp and marsh, through wet meadow, to Agropyron–Carex grassland and to various wooded communities, and also of marsh, through Drepanocladus–Carex bog to a Larix laricina association. The main bog sere of the region is initiated by some kind of aquatic or marsh phase and passes through Sphagnum bog stages to bog forest (Picea mariana) climax. Ecological aspects of Sphagnum species are considered in relation to succession and a regeneration cycle. Retrogression caused by burning is described for marshes, bogs, and bog forests. Many bogs in the northern part of the region have large mounds and ridges that retain frozen peat below the surface mantle during the summer. The significance of these permafrost areas is discussed. Brief consideration is given to phytogeographical features of the region.

Vegetation and Substrate of Cranberry Glades, West Virginia

1. The Cranberry Glades area in West Virginia comprises about 600 acres of apparently level land covered with bog forest, shrub, and areas of sedges, mosses, and lichens, commonly called "glade." Most of the area is underlain by peat or organic material from a few inches to 11 feet in thickness. 2. The level area, upon which 15 feet of inorganic material and peat have accumulated, represents a part of the Harrisburg peneplain temporarily base-leveled in the soft shales and sandstones of dipping strata. 3. Bog conditions were initiated by the deposition of levees along the banks of streams, causing undrained conditions in the areas away from the streams. This change from degrading to aggrading action probably occurred during glacial time, when the streams, swollen by increased precipitation and decreased evaporation and overloaded with sediments from slopes unprotected by sufficient vegetation cover, deposited their sediments over the area. In post-glacial time the streams with reduced volume of water slowly built their levees higher during floods, causing further damming and further peat accumulation. 4. Six plant communities are differentiated: sedge-sphagnum, sphagnum-cranberry-beaked rush, moss-lichen, bog forest, and two shrub communities. 5. The structure and pollen of the transect profiles of the sediments and the existing communities point to succession from shallow water, with its accompanying communities, to a sedge swamp, to a retrogression to sphagnum, to mosslichen in some parts, to shrub, to bog forest. 6. Succession will continue until bog forest has occupied the whole area, to be followed by regional climax forest only when sufficient stream erosion has removed the peat accumulation and provided sufficient drainage.

The Successional Role of Southern White Cedar, Chamaecyparis Thyoides, in Southeastern North Carolina

A community in which the southern white cedar, Clhaiaecyparis tlyo ides (L.) BSP., is dominant occurs on peat soils of the Atlantic coastal plain. Such f orests are neither common nor extensive in view of the enormous areas of peat land in this region. The most complete study of southern white cedar is that by Korstian and Brush ('31). This study, together with those of previous investigators, supplied ecological information such as site characteristics, the aspect of the community, associated tree species, and some features regarding reproduction. The site occupied by the southern white cedar community is consistently peat bog underlain by sand (Korstian, '24; Korstian and Brush, '31). Korstian has pointed out that, with larger proportions of silt and clay in the underlying mineral soil, swamp hardwoods are more abundant. Hardwood-cypress swamps are underlain by clay or sandy-clay subsoil. The aspect of the southern white cedar forest has been described and illustrated adequately. Gifford ('00) gave a description of the community in which he emphasized the extreme density of the forest, the trees growing so close together that they afford mutual support and the bases of the crowns meeting to form a solid canopy. He mentioned the dense undergrowth, but neither he nor any of the other workers has analyzed its composition except to note that it consisted of a dense growth of vines and shrubs. Although Harper ('26) listed associated species of all categories, trees, shrubs, lianas, herbs, and bryophytes in order of their abundance in his account of a middle Florida cedar swamp, the cedars were not the largest nor most conspicuous trees in this community. It must therefore be considered as a mixed bog forest which cannot be compared with the true cedar community. Although Korstian and Brush ('31 ) found that pure, dense, more or less even-aged stands are most characteristic f or the southern white cedar, they listed numerous arborescent associates. The number of associated tree species is greater in the southern part of the range than in the northern part. It is apparent from the literature that southern white cedar reproduction requires decidedly open conditions. Pinchot ('00) noted that no reproduction occurs after crowns meet to form a continuous canopy. Korstian and Brush ('31) likewise found that seedlings do not tolerate the shade of the cedar forest. They pointed out that, although the seedlings may start under cover of bog shrubs, the shrubs usually develop rapidly into an impenetrable jungle making establishment of the cedar difficult. Ackerman ('23) found that seedlings come up in abundance in the rollways and tramways after logging, but that elsewhere the slash and the rank growth of shrubs and vines produce a mass which the young cedars have small chance of penetrating. This situation was recognized likewise by Korstian and Brush ('31). It is significant in this connection that in New Jersey the southern white cedar constantly invades cranberry bogs (Gifford, '00). Recognizing the requirement for an open seed bed, at least one free from the extreme competition of the bog shrubs and lianas, several authors suggested clearing to obtain reproduction. In view of the dangers involved in controlled burning in such areas, Ackerman ('23) suggested the use of cat-

A Bog Forest

In a previous paper (4, I9I7) the writer has described forest succession in Puget Sound sphagnum bogs, and in other papers (4, I9I3; I9I4; I9I9) has listed the trees growing in various sphagnum bogs of the Puget Sound region and Alaska. All of these are comparatively early stages in bog succession. None of them have reached a stage where the forest is dominant. An area of about three acres near Victoria, British Columbia, shows a very late stage where the forest has become the dominant vegetation, and sphagnum is no longer found living. This area was visited in July, 1920, and a more careful study was made during several visits to it at various times in July, I92I. The area is at present bordered on the south by a meadow, on the east and north by Lost Lake, and on the west by the Patricia Bay line of the Canadian National Railway. The forest consists of a pure stand of lodge-pole pine, Pinus contorta. The trees are of good size for this species, many of them being 20 to 30 feet tall and 6 to io inches thick at the base. A few are 12 inches thick. The stand of trees is very dense over nearly all of the area, and many young trees have been killed by the shade of the taller ones. The trunks of these trees are straight and slender. They do not have the scrubby form that this species does on rocky, exposed places, nor the stunted appearance that it has in the early stages of forest succession in Puget Sound bogs. Very few pine seedlings were found, and these only on the border along the west side, where the forest was cleared a few years ago when the railroad was built, and Nature was then allowed to take her course again. Lodge-pole pine is common on this portion of Vancouver Island. It is found around lakes, both in swampy places and on rocky shores, and on the thin soil of rocky hills. It is found practically to the top of Mount Benson, near Nanaimo. Glendenning (i, i9i8) says that it is frequent in bogs and on gravel ridges in the Cowichan district on Vancouver Island. Whitford and Craig (5, i9i8) state that this species is general throughout the province of British Columbia, from the international boundary to the Yukon drainage, being found at an altitude of 5,ooo to 6,ooo feet, and attaining a height of 50 to 75 feet and a diameter of I2 to 24 inches. The undergrowth in the bog forest under consideration consists of a dense thicket of Labrador tea, Ledum qroenlandicum, and salal, Gaultheria shallon.