Progress in succession in the Pennington grove of Pinus virginiana

In 1932 the senior author reported on an ecological survey in stands of Pinus virginiana in Munroe County, Indiana, viz. the Pennington grove near Weimer Lake, two miles sw. of Bloomington, on highway 45, and the Christie-Freeman groves, four miles nw. of Ellettsville. At the time of the 1931 survey very little ground cover had developed in either of these groves. The repesent study considered only the Pennington grove. This stand has seen no decided cultural modifications since the 1931 survey. Periodic surveys were made in the stand by various groups of ecology students of Butler University. These surveys showed a definite trend in succession which now definitely forecasts replacement of the 100 per cent coverage of crown by Pinus virginiana. The invaders consist of a large number of broadleaved species. The forst floor, which in 1931 was almost bare, is today extensively covered by herbs and the seedlings of tree and shrub species. The authors made a survey in July and September of 1947 to define in quantitative terms the trends in succession in the Pennington grove

A pollen study in the tension zone of lower Michigan

A transition zone between two large vegetation cover types always presents a tantalizing aspect of vegetational characteristics, frequently suggesting instability. In such areas the microclimate of edaphic factors favors first one and then another group of species which are characteristic components of one of the other of the flanking formations, or smaller fluctuations in temperature and moisture find expression vegetational changes which will not be evident within the boundaries of the definitely expressed formations. This is emphasized boldly by disjunct distribution or intermingling of species of these flanking climaxes, where habitat exerts selective action far greater than is possible under optimum climax control; this may at times even dim the real climax status. As Dachnowski (3) points out, pollen profiles can here, perhaps, give the most reliable picture of the climatically flavored vegetation. It is, therefore, also logical to expect that small variations, or fluctuations, in climate ought to be recorded first in such tension areas by minor changes in vegetation, especially by variation in degree of importance of certain genera in the association complex

A Quarter Century of Botany at Butler University

Kingdoms, inventions, masterpieces in literature, art, music, and architecture are born out of dreams. They may seem flimsy and elusive but they show the things which are closest to the heart far down the lapse of time. For, building along the lines of dreams makes realities.The Butler Botany Department was once upon a time just such an elusive, tantalizingly uncertain dream of a young Ph. D., a dream which occupied his mind when the ink had barely dried on the signatures to his diploma which the University of Michigan had presented to him as tangible evidence of years of intensive preparation for the teaching profession in the field of botany

The Pine Barrens of New Jersey: A refugium during Pleistocene Times

In 1943 Potsger and Otto (13) published the first paper on the pollen analyses of New Jersey peat which involved a series of five bogs from northern and northwestern New Jersey. These bogs represented a rather large geographical area, but their message was unusually uniform. One might, therefore, be justified to assume that the study gave a rather trustworthy history of the vegetation of the glaciated part of the state. From a forest constituted almost entirely of Abies, Picea, and Pinus, succession carried dominance to a pronounced Pinus period. This genus contributed as much as 80% of the pollens at these particular foot-levels. In the upper third of the sediment an association of Tsuga dn Quercus depressed Pinus considerably; and in the topmost levels Castanea entered as last invader of the crown cover

The Forest Primeval of Indiana as Recorded in the Original U.S. Land Surveys and an Evaluation of Previous Interpretations of Indiana Vegatation

Between 1799 and 1846, the territory which now comprises the State of Indiana was divided by the United States public land survey into six-mile-square townships as a prerequisite for the equitable distribution of public lands. Each township, in turn, was subdivided into 36 sections one-mile square. Section and quarter-section corners, as well as a number of intermediate points, were marked by blazing trees. The location, name, and diameter of more than 214,500 witness trees, composed of more than 80 species and generic groups, were recorded in the Indiana surveyors\u27 journals. These journals and the maps compiled from them, records inscribed before a tidal wave of settlers swept away much of the natural vegetation of the State, represent our most tangible account of Indiana\u27s primeval forests. They are the source of data for this study

Distribution of Quercus muhlenbergii in Indiana

In a complex forest association such as found in Indiana one is confronted with interesting distribution patterns of some species. These same species may to some degree all associate in the mixed mesophytic forest association. All of them are adapted to the macroclimate but can be segregated from the climax association complex into smaller individual groups by variations of the microclimate. This is determined by physiographic conditions which may modify aerial and edaphic factors. Potzger has discussed this phenomenon as operative in distribution of sugar maple, beech and white oak. Potsger and Friesner referred to it in Quercus rubra and Q. velutina. All of these segregations are, of course, due to modifications of the macroclimate in more or less limited areas. It is quite obvious that identical soil and physiographic factors in Indiana and northern Michigan, let us say, could not involve segregation of the same genera and species with small variations in the edaphic and aerial factors because of the major selection of species by the macroclimate, or generalized climate, which is greatly different in the two locations

Characteristics of the Original Vegetation in Some Prairie Counties of Indiana

During the century since civilized man brought great change to the natural vegetation of Indiana by lumbering and farming, the prairie suffered perhaps more than the forest. Agriculture and drainage modified these habitats greatly. An attempt is therefore made to reconstruct the pattern of the original distribution of grasslands in Indiana. Rohr and Potzger described and discussed three northwestern Indiana prairie counties and the present study concerns itself with the prairie-influenced counties to the south and east of those described previously. In the five counties presented in this study the mesophytic forest was almost entirely inhibited and the most favorable areas were occupied by xeric oaks, or oaks and hickories, and even such forests could not always produce a closed canopy

Pollen Study in the Gatineau Valley, Quebec

The authors have repeatedly made reference to the complexity of Quebec\u27s past glacial and forest history, determined in part by the wasting Laurentide ice center, sea invasion, large pre-glacial lakes, altitudinal differences between the Shield and the St. Lawrence valley, as well as by the developments in the history of the Great Lakes

Forests of the past along the coast of southern Maine

Pollen analysis in North America is gradually adding more and more significant facts on the history of our forests in glaciated North America, showing likenesses and differences in succession in the various geographical locations; throwing into bold relief definite patterns of forest development for a given region or for several regions. Forest types also suggest climatic changes and fluctuations which made such forest types possible. Up to the present our eastern coastal areas received less attention from the pollen analyst than the interior central states. The analysis of peat from New Jersey by Potzger and Otto (7) and the studies by Deevey (3, 4) in Connecticut made at least a beginning in pollen study along the Atlantic coastal areas. They also accentuate the need of further studies along our eastern border to add to the completeness of the picture with respect to forest succession during post-glacial times, especially northward of the New Jersey and Connecticut stations. The present study has this expansion of area as its specific aim

Contrasts in certain physical factors in Fagns-Acer and Quercus-Carya communities in Brown and Bartholomew counties, Indiana

Oak-hickory forests occur in Indiana under three sets of ecological conditions. First, in the northern fifth of the state, roughly north and west of the Tippecanoe river (except for the northeast corner, i. e., Steuben and part of Lagrange counties), they are the most mesophytic type of forest that will be permanently maintained by the general climate of the area and, therefore, become the climax association