Permanent Flooding in a River-Bottom Timber Ares

BULLETIN of the ILLINOIS NATURAL HISTORY SURVEY HARLOW B. MILLS, Chief

Effect of Permanent Flooding in a River-Bottom Timber Ares

LEE E. YEAGER

Printed by Authority of the STATE OF ILLINOIS ADLAI E. STEVENSON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION NOBLE J. PUFFER, Dirtcfor

S T A T E OF ILLINOIS Adi.ai E. Stevenson, Governor BEPARTMENT OF REGISTRATION AND EDUCATION

Noble J. Puffer, Director

NATURAL HISTORY S U R \' E Y DIVISION

Harlow B. Mills. Chief

Volume 25 BULLETIN Article 2

Effea of Permanent Flooding

in a River-Bottom Timber Area

LEE E. YEAGER

Printed by Aulhority of thr State of Illinois

URBANA, ILLINOIS

August 1949 STATE OF ILLINOIS Adlai E. Stevenson, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Noble J. Puffer, Director BOARD OF NATURAL RESOURCES AND CONSERVATION

Noble J. Puffer, Chairman A. E. Emerson, Ph.D., Biology George D. Stoddard, Ph.D., Litt.D., L.H.D L. H. Tiffany, Ph.D., Forestry LL.D., President of the University oj Illino L R. HowsoN, B.S.C.E., C.E., Walter H. Newhouse, Ph.D., Geology Engineering Roger Adams, Ph.D., D.Sc, Chemistry NATURAL HISTORY SURVEY DIVISION Urbana, Illinois Scientific and Technical Staff Harlow B. Mills, Ph.D., Chief Bessie B. Henderson, M.S., Assistant to the Chief

Section of Economic Entomology Section of Applied Botany and Plant Pa thology George C. Decker, Ph.D., Entomologist and Head Leo R. Tehon, Ph.D., Botanist and Head Entomologist Cedric Carter, Ph.D., Plant Pathologist J. H. Bigger, M.S., J. L. L. English, Ph.D., Entomologist J. L. FoRSBERG, M.S., Associate Plant Pathoh Entomologist gist C. J. Weinman, Ph.D., S. C. Chandler, B.S., Associate Entomologist G. H. Boewe, M.S., Assistant Plant Pathologi Willis N. Bruce, M.A., Assistant Entomologist Robert A. Evers, M.S., Assistant Botanist John M. Wright, M.A., Assistant Entomologist Joan H. Laube, B.S., B.M., Technical Assista' H. B. Petty, M.A., Associate in Entomology Section of Game Research and Manage Extension ment Section of Faunistic Surveys and Insect Ralph E. Yeatter, Ph.D., Gaine Specialist

Identification Frank C. Bellrose, B.S., Associate Game .?/>. H. H. Ross, Ph.D., Systematic Entomologist cialist and Head Harold C. Hanson, M.S., Assistant Game Sp, Milton W. Sanderson, Ph.D., Associate Tax- cialist onomist James S. Jordan, M.F., Assistant Game Tect nician Lewis J. Stannard, Jr., M.S., Assistant Tax- onomist William Nuess, Laboratory Assistant Leonora K. Gloyd, M.S., Laboratory Assistant Cooperative Wildlife Research Philip W. Smith, B.S., Laboratory Assistant (Lllinois Department of Conservation and V.. Technical Library Fish and Wildlife Service, Cooperating)

Marguerite Si.mmons, M.A., M.S., Technical Paul J. Moore, B.S., Project Leader Librarian George C. Arthur, B.S., Project Leader Lysle R. Pietsch, M.F., Project Leader Section of Publications and Public Rela- John C. Calhoun, B.S., Assistant Proje- tions Leader

Ja.mes S. Ayars, B.S., Technical Editor and William J. Harth, M.S., Project Leader Head of Blanche P. Young, B.A., Assistant Technical Section Aquatic Biology Editor George W. Bennett, Ph.D., Aquatic Biologi. Charles L. Scott, B.S., Assistant Technical and Head Photographer William C. Starrett, Ph.D., Associate Aqua, ic Biologist Section of Forestry D. F. Hansen, Ph.D., Assistant Aquatic B> Willet N. Wandell, M.F., Forester and Head ologist Lawson B. Culver, B.S., Associate in Forestry R. Weldon Larimore, M.S., Research Assisi Extension ant Robert K. Stubbs, B.S., Research Assistant Daniel Avery, Field Assistant

Consultant in Herpetology: Hobart M. Smith, Ph.D., Assistant Professor of Zoology, University o Illinois,

This paper is a contribution from the Section of Forestry- (77567—4M— 4-49) CONTENTS

Acknowledgments 33

\rea Studied 34

?TUDV Procedure 35

FiMBER Types 37

A'ater Levels 39

Free Mortality 41

Trees Standing in Water 41

Trees Standing in Mud 43

Trees Standing on Land 46

Discussion 47

Pree Fall 51

Rate and Manner of Falling 51

Fate of Fallen Trees 52

^ost-Floodixg Succession 54

Plants 54

A'lammals 57

Birds 61

UMMARV 63

ITERATURE Cited 65 .>,^i^

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Bji

U Effect of Permanent Flooding

in a River -Bottom Timber Area

LEE E. YEAGER*

WATER impoundments, varying having a strong probability of increasing from simple fish ponds to the in importance. vast programs now being spon- The objective of the study on whicii sored by the United States Corps of En- the present report is based was to deter- gineers and the Bureau of Reclamation, in- mine the rate of flooding mortality in var- vohe many changes in the American land- ious Mississippi River \alley tree species scape. Practically every major stream and and the rate and effect of tree fall ; in hundreds of smaller ones ha\e been or, the course of the stud\ , brief consideration if present proposals are consummated, will was given to plant and animal succession be affected by dams erected for power de- following the death of timber stands. The velopment, channel improvement, flood report covers principally the period begin- and erosion control, and other purposes. ning in September, 1939, and ending in The environmental eftects inherent in this October, 1946. nation-wide program are potentially of great importance to wildlife, inland fisher- ACKNOWLEDGMENTS ies, bottomland forests, and agriculture. during One of the problems associated with My obligations for assistance 1 indebted, stream damming and resultant impound- this investigation are many. am first of all, to the late Dr. Theodore H. ments is that of flooded timberland. On of the Illinois Nat- many projects, especially where public Frison, former Chief proposed the funds are involved, the areas to be ural History Survey, who Tehon, during flooded are cleared of trees and brush. On study. To Dr. Leo R. Chief of others, clearing may be done only partly part of the study period. Acting Natural History Survey, and to Dr. or not at all, because of shortage of funds, the the or because of bad weather, high water, or Gustav A. Swanson, formerly with and Wildlife Service, I owe thanks other reasons. Flood-killed timber is gen- Fish erally considered by the public as un- for the co-operative arrangement wherein I permitted to complete field obser- sightly, and complaints concerning it may was in planning the be strong. Dead trees that reach navigable vations. Dr. Tehon aided also streams after falling offer certain hazards in\estigation and Mr. G. H. Boewe, with initial to shipping, commercial fisliing, and of the Survey staff, assisted other enterprises associated with inland field work. Dr. Cornelius H. MuUer, waterways. Therefore, whether from the while with the Natural History Survey standpoint of aesthetics or economics, as a botanist, made the detailed vegetation whicli later work was based. For flood-killed timber is a problem, and one map on data used in preparing fig. 5, I am in- * Formerly Forester, Illinois Natural History Survey, debted to the St. Louis District, Corps of Urbana, Illinois. Since May, 1945, with the United States Fisli and Wildlife Service; present station, l.c.idcr. Colo- Engineers, Department of the Army, Sev- rado Co-operative Wildlife Research Unit, Colorado Agri- specialists of the Natural cultural and Meclianical College. Fort Collins. Colorado. eral wildlife The major portion of the investigation on which the History Survey or co-operating organiza- present paper is based was made while lh« author was employed by the Natural History Survey. Completion tions gave valuable help: Mr. Charles S, of the study was accomplished through a co-operative Spooner, Jr., was of much assistance in arrangement between the Survey and the Fish and Wild- life Service, mapping; Mr. Frank C, Bellrose, Dr.

[33] 34 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

Ralph E. Yeatter, Mr. Harry G. Ander- Point was formed by the confluence of thf son, Mr. Charles McGraw, and Mr. Wil- Mississippi and Illinois rivers. let N. Wandell provided numerous rec- At other than flood periods, previous ords and were helpful in other ways; and to 1938, the 2,200-acre Pere MarquetU Mr. Robert G. Rennels made careful anal- area, roughly 1 by 4 miles, was character- \sis of food-habits material. Mr. Carl ized by numerous wooded ridges, flats Pohlman, a resident of Calhoun County, and wet-weather sloughs, several small gathered valuable records on the fur take. lakes, a number of small marshes, and the Mr. James S. Ayars, Mr. Robert E. Hes- margins of two large rivers. In June, selschwerdt, and Dr. H. H. Ross, editor, 1938, gates of the recently completed Al- photographer, and systematic entomolo- ton Dam, 20 miles downstream on the; gist, respectively, of the Illinois Natural Mississippi River, were closed for the first History Survey, are responsible for most time. This closure resulted in flooding sev- of the photographs used here as illustra- eral hundred acres of the area, normally tions. Mr. Ayars' assistance with editorial land. Although the gates were opened problems is gratefully acknowledged. a few times after June, 1938, the higher than normal water level that prevailed AREA STUDIED through much of the 1938 growing season, fig. 5, was sufficient to affect plant Detailed work forming the background species sensitive to flooding. for the present report was done on the By the summer of 1939, 600 acres (27 Pere Marquette Wildlife Experimental per cent) of the area were permanently Area, locally known as Calhoun Point, in inundated; 1,600 acres (73 per cent) lay Calhoun County, Illinois, fig. 1. Calhoun above pool level, which was 15.3 feet

ILLINOIS STATE NATURAL HISTORY SURVEY

PERE MARQUETTE WILDLIFE EXPERIMENTAL AREA AND MIGRATORY WATERFOWL REFUGE

Fig. 1.—Air view of Calhoun Point, Calhoun County, Illinois, May 1938, prior to flooding. Aimust, 1949 Yeager: Effeit of Permanent Flooding 35

at Grattdii, 2 miles downstream. Prior to 3 months after the date of permanent in- the Alton impoundment, annual fluctua- undation. (The Alton Dam had been tion of the Mississippi and Illinois rivers closed during the summer and a part of in the locality varied from subgage lows the fall of 1938, fig. 5.) The first rec- to floods exceeding 25 feet. Even after the ords taken by the writer were before any impoundment, severe floods occurred in of the trees had died, although the pin 1043 and 1^44 and a lesser flood in 1945. oaks and a few trees of other species Permanent flooding increased the average showed effects of an abnormally high summer water stage by about 3 feet. Ma.\- water stage. imum ele\ation on the area before im- In the six sample transects, 1, 2, 6, 7, poundment was 10 feet; at pool level, 8, and 11, each living tree and shrub, re- after impoundment, the highest ridges gardless of species, size, or condition, was were only 7 feet above the water surface. tagged for future inspection, except «in These figures indicate the very low relief pure stands of maple or elm on land, or of the Pere Marquette area. in large clumps of waterprivet or buttonbush in water, where only every sec- STUDY PROCEDURE ond, third, or fifth tree or shrub was tagged. Markers or tags were of 14-gage

Kasic to the work reported here \\as galvanized sheet metal, about 1 by 2 a detailed vegetation map of the area inches in size, each perforated at one end, prepared by Cornelius H. Muller while and numbered consecutively. Attachment with the Natural History Survey's Sec- was by means of sixpenny galvanized tion of Applied Botany and Plant Pa- nails, at a height of about 4.5 feet. In thology. Muller did his field work between each transect the tags faced one direction, February 8 and June 11, 1938, shortly always that opposite to the direction of before initial flooding of the area was progress, thus facilitating both attachment begun. In mapping the area, he estab- and relocation. Transects were marked at lished 1 1 transects, each 50 feet wide, each end and at \ arying intervals by ap- that \aried in length from 600 feet to 1.1 propriately numbered signs. miles and totaled 5.9 miles. Records made at the time tags were at- Muller established the transects after tached and at all succeeding inspections he had made a general reconnaissance were kept on the same form. At the first map of the many minor vegetation t>pes inspection, made when tags were at- distinguishable. He did not space the tached, the number was recorded for each transects uniformly or orient them parallel tree, and with it the tree species, d.b.h., with each other, but laid them out to cro\\'n class, and general vigor as near as cross as many as possible of the water this could be estimated. Where water oc- channels and sloughs then present on the curred, the depth at the base of each area and to traverse in a representative tagged tree was recorded. At each suc- way as many as possible of the vegetation ceeding inspection, the condition of the types. tree and the water depth, which varied as He mapped the transects in such detail shown in fig. 5, were the main records as to show the location of all trees, all t iken. Trees obviously dying, but still large shrubs, and most of the herbaceous with green lea\ es or cambium, were so plant areas within them, recording species recorded. Observations were made in (substantiated by specimens deposited in June and October, 1940; one record was the Illinois Natural History Survey her- taken in June, 1941, one in October, barium), diameters of trees, sizes of 1942. and another in October, 1944, shrubs, and density of herbaceous cover. table 2. 'The final record was taken in The location of si.x transects, 1,2, 6, 7. October, 1946. A total of six inspections, 8, and 11. totaling 3.5 miles, is shown in in addition to those at the time of tagging fig. 2. These transects constitute the and on numerous visits at other seasons, sample used as a basis for the present supplied data for this report. paper. Supplementing the detailed investiga- Active field work on the effect of flood- tion in the Pere Marquette area were ob- ing was begun in September, 1939, about servations made in flooded areas along the 36 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

PERE MARQUETTE WILDLIFE EXPERIMENTAL AREA GRAFTON. ILLINOIS

Fig. 2.—Land and water areas on the Pare Marquette Wildlife Experimental Area, Calhoun Point. Orientation of the six transects supplying sample data is shown by straight, heavy lines. The direction of flow of the Illinois and Mississippi rivers in this area is approximately north-, east.

Mississippi River in Jo Daviess, Hender- tions, confirmatory in nature, are not in- son, and Pike counties, and along the Illi- corporated in this report. nois River in Mason and Jersey counties, Common and scientific nomenclature in all in Illinois. These areas were similar to this paper is, in most instances, based on Calhoun Point except that they were nar- the following authorities: Kelsey & Day- rower, were bordered by large rivers along ton (1942) for plants; Necker & Hat-

only one side, and supported greater pro- field ( 1941 ) for mammals ; American Or- portions of willows and cottonwoods in nithologists' Union (1931) for birds. the stands. The supplementary observa- Some forms were not identified to species. August, 1949 Yeager: Effect of Permanent Flooding 37

TIMBER TYPES position, size classes, and the scientific names of all important trees and shrubs Most of Calhoun Point, at the time of contained in the samples are indicated in permanent flooding, was co\'ered by river- table 1. bottom forest characteristic of that found Silver or soft maple was the most in the upper Mississippi River valley. abundant of the large trees in the flooded The stands, varying from sapling to ma- area. On the lowest level on which trees ture growth, contained scores of very grew, it easih' dominated all plants ex- large, decadent, and often dying silver cept semiaquatic species, such as black maples, with an occasional elm, sycamore, willow, buttonbush, waterprivet, and and pin oak of similar type, fig. 3. Com- waterlocust, tig. 4. Many of the maple

1 i;;. J. Il.,^>, . . . : :ii,i:,.: L, and characteristically mullihi ancheil maples, elms, oaks, and sycamores were found in the Calhoun Point stands, October, 1940. 38 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

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lats held standing water during tiio rain\ 'Hie Pcre iMarquette area is north of easons. Maple was also a dominant the range of haldc\press and water tupelo pecies on some higher sites, including un- (Taxodiuiii distlchum and A'.vffa aqua- looded ridges. American elm, pecan, and tica) and evidently of certain other south- ugar hackberry reached their best devel- ern river-bottom species, such as blackgum ipment at slighth higher ele\ ations. Ash (Nyssa sylraticaj, American sweetgum

Fig. 4.—Typical stand of silver maple I htiilK IV4u. Dead and dying trees n background.

,vas often found on lower sites occupied ( Liqitldaiiibar styraciflua), and the magno- irincipalU' by maple, but occurred at all lias ( MayiuAia spp.), which were not rep- levations. Species of secondary impor- resented. The area lies considerably south ance on elm-ash-pecan sites included per- of the midwestern occurrence of tama- simmon, river birch, hawthorn, and holh'. rack (Larix laricina), spruce (Picea spp.), On the highest land flooded, originally balsam fir (Abies balsaiiiea), and north- he lower ridges, pin oak, persimmon, cot- ern white-cedar (Thuja occideiitcdis) :onw()()d, and several less important Black ash (hraxinus iiit/ra), which occurs ;pecies were found. VVaterlocust grew in Illinois, was not found in the area. iiainly on shore lines but sometimes on 'idge sites; waterprivet and buttonbush WATER LEVELS .vere confined to shore Imes and shallow ;loughs, both species often occurring in a That the water stage at Calhoun Point, 'oot or more of water. Found on un- even after closing of the Alton Dam, looded land, particularly on the higher fluctuated considerably is shown in fig. 5. idges, were boxelder, red mulberr\', red- Fluctuation was due in part to winter lud, dogwood, American plum, honey lo- drawdowns in 1938-39 and 1939-40, to :ust, and Kentucky coffeetree, none of unusualh' high floods during the springs .vhich appeared on the Hooded pcjrtion of of 1943 and 1944, and to a less severe :he samples, table 1. Hi)(jd in the spring of 1945. Several minor 40 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

J FMAMJJ A50ND|J FMAMJJ AS0NDJFMAMJJA50NDJFUAMJJ A50ND 1937 1936 1939 1940

30 Aufiust, 1949 Yeacer: Effect of Permanent Fi.ooniNn 41

fluctuations in water Ie\ el came at otlier show the effect of flooding on these spe- times. With the exception of the three cies b\ diameter classes and water depths, spring; floods, the more pronounced respectixely. Trees indicated in the "land" changes came during the dormant season classification were on unflooded area at and presumahly had only a minor effect on pool stage; trees in the "mud" classifica- woody species. The peaks of the 1943 and tion were well above the original perma- 1944 floods occurred during cool weather nent water level but, subsequent to flood- before the growing season was fully under ing, mainlv along the new shore lines way, at least for trees. and other low areas of mudd\- nature; trees in the "water" classification were TREE MORTALITY entireh' on newly flooded land, except for willow and buttonbush. These two spe-

Although it is universally known that cies, therefore, did not occur in the "land" most trees and shrubs die when subjected sample, nor did boxelder, red mulberry, to permanent flooding, the rate of d\ing, and several less important species in the by species, diameter classes, and depths "water" sample. The effect of flooding on flooded, has received little specific stud\-, trees under "water," "mud," and "land" and is not well known. Green (1947) re- conditions is discussed below. ported on the only other study on this subject known to the writer. His work, Trees Standing in Water also in the upper Mississippi River vallev, covered the period 1939—1944. \'irtually all trees permanently flooded Table 2 indicates roughly the rate of to a depth of 20 or more inches were dying in common upper Mississippi River dead b\- 1946, 8 years after the initial im- valle\' trees and shrubs in the Calhoun poundment, fig. 6. Species \aried consid- Count) stud\' area, and tables 3 and 4 erabh' in rate of mortalitv, table 2. Onl\' ^

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Fiji. 6. —Mcjsl trees and shrubs Hocnleii to (lei>ths ab()\'e the root collar died in 1 to 6 years. Shown above is a watcrprivct, relatively resistant to flooding, that died during the fourth year when Hooded 20 inches. The large tree is a persimmon, which died during the second year. A heavy mat of duckweed covered the water in this area. The writer, taking notes, October, 1941. 42 Illinois Natural History Survey Bulletin Vol. 25, Art.

00 August. 1949 Yeacer: Effect of Permanent Flooding 43

Fig. I.— Diameter of tree or shrub had little effect on survival after Hooding except in serai- aquatic species and in reproduction sizes. In the area pictured above, all trees of 3 to 30 inches (larger trees in background) had succumbed by October, 1946, in 8 years of permanent flooding.

buttonbush, willow, and, to a less degree, buttonbush, and black-willow shrubs or waterprivet appeared to be adapted to trees still survived in water over 20 inches conditions induced by impounded waters. deep, table 4. More than half of the Buttonbush did not succumb except waterprivets and willows were dead by where completely, or nearly, inundated. October, 1946. Before 1938, willows The few ash trees still living in October, grew naturall\' in water or on the banks 1946, were obviously dying. of sloughs and were flooded to greater

Trees and shrubs of the various di- depths than any other tree species ; the ameter classes showed little differentiation depth averaged approximately 3 feet on in survival ability after flooding except the lower (northern) end of Calhoun in the 2-inch class, table 3. In this class Point. Had willows occurred in position the difference was due to species (water- to sustain all depths of inundation, a privet and buttonbush, both semiaquatic) higher percentage of survival probabl\ rather than to size, fig. 7. In general, would have resulted. To all but seini- healthy, vigorous trees of each species aquatic species, permanent flooding to a showed the greatest resistance to flooding, depth of 20 inches or less above the root and the very small and the overmature collar was fatal. classes of each species showed the least resistance. Trees Standing in Mud Trees and shrubs still living and vigorous in 1944 were, in all cases, on the less Trees in mud, in coinparison with trees

deeply flooded areas ; only waterprivet, standing in water, showed a more or less I

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— — 1)^:0 01 w > o = C c •r ^ u t i- fe. c o S c c H uO 46 Illinois N.'vtur.ai. History Survey Bulletin Vol. 25, Art. 2 parallel, but less severe, mortality rate, this kind clearly are waterprivet and but- table 2. In the transects selected for tonbush, as would be expected. By 1946, it study, the number of trees in mud was appeared likely that a higher percentage small ; also, the ultimate effect of mud, of trees of all species would die in time, after 8 years, was less obvious than that and that the mud flats would support cat- of water, since reactions in this medium tail (Typlia latifolia) or other marsh were slower. plants, or grow up to willow, cottonwood, In view of the small area of mud in the white ash, and perhaps other forest repro- transects, supplementary observations were duction, fig. 20. Extensive invasion of] made in October, 1944. The data cattail, and, in some cases, arrowhead or* obtained vary from those of the transect duckpotato (Sagitlaria spp. ) , fig. 8, had samples only in method and places of col- occurred prior to the extreme floods of lection. As presented in table 5, the sup- April and May, 1943 and 1944, which} plementary data represent a special effort destroyed most of them. In 1946, these- to enlarge the mud sample, particularly marsh plants were reappearing. for Cottonwood, birch, hackberry, persim- In a study of the influence of flooding mon, pecan, buttonbush, and pin oak. in upper Mississippi River pools, Green They were collected from strips running (1947) noted few deleterious effects on parallel to mud fiats rather than at right timber growing on land higher than the angles to them. These parallel strips contour 2 feet above normal pool level. were near transects 1, 6, and 7, and were In the present study, the "mud" sample

30 to 50 feet wide ; trees were taken in lay lower than the 2-foot contour, being order of occurrence, regardless of species, in fact where the water table lay at or very, size, or condition. It is believed that this near the ground surface. Green noted procedure eliminated the error of selectiv- the appearance of forest reproduction on ity, and, since the two sets of data show cleared area between pool stage and the similar trends, together they give added 2-foot contour. Similar observations werei reliability to the conclusions. recorded many times during the present Raising of the water table so as to turn investigation. low ridges into mud flats resulted in timber mortality at the end of 6 years that Trees Standing on Land ranged from 50 per cent to nearly 100 per cent, except for such species as privet, Even for land not actually flooded the white ash, river birch, and Cottonwood. water table was raised approximately 3. The species best able to tolerate change of feet as a result of closing the Alton Dam.i

Table 5.—Mortality in various species of trees on mud sites in study area, Calhouni County, Illinois, October, 1944. Permanent flooding of area was begun in June, 1938.

Species August, 1949 Yeager: Effect of Permanext Flooding 47

8.- i Fi^. — Cattail, rice i- u _ i- iiclipotato. smartweed, and other marsh or moist-soil plants invading timheriand where the \Nater tahle hati been raised to the soil surface. Timber stand is dead or dying. October. 1941.

1 hat timber stands were attected thereby two very large, old hawthorns, among 17 was apparent, though not conspicuously trees of this genus growing on land in the so except in pin oak. This species, even transects, is believed to have resulted from i)n the unrtooded land, suffered a mortal- natural causes, rather than flooding, as ity of 28.2 per cent by October, 1944, lit- other hawthorns growing outside of the tle iTiore than 6 years after initial transects were obser\'ed to be tolerant of impoundment, and d\ ing was noticeably the raised water table. progressive. Mortality in other common species was much lower, table 2. White Discussion ash, pecan, cottonwood, waterprivet, and several other species on unflooded land Pin oak was easily the species most sus- showed no loss as a result of the rise in the ceptible to injury by flooding, showing water table. Willow and buttonbush sNiiiptoms of dying as well as complete were not represented in the land sample. mortality before any other. Pin oak trees By October, 1944, the two most numer- flooded in June, 1938, were clearly in a ous species on the area, silver maple and dying ct)ndition in September, 1939; by American elm, showed losses of 5.1 and June, 1940, over 70 per cent had died, 6.1 per cent, respectively, probably some- table 2. All were dead b> October, 1940. what greater than natural mortality in In water, river birch indicated a slightly stands where large poles and standards higher mortality rate than pin oak by predominate. On land, the greatest loss June, 1940, but a somewhat slower dying in both maple and elm. as well as other rate thereafter. Pin oak trees in mud species, was in the very large, overmature and on land sites with raised water le\els trees. The other coinmon river-bottom died less rapidh' than those in water, but species, persimmon, hackherry, and water- all in mud succumbed before October, locust, showed only slightly lower death 1942, little more than 4 years after the rates than maple and elm. The death of original impoundment. A water table 48 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

raised to the ground le\el (trees in mud) and fourth, respectively, in rate of dying. was less injurious to river birch than to The approximate number of years at which pin oak. Of the trees in water, hawthorn various species reached 100 per cent mor- and silver maple, in June, 1940, were third tality is shown in table 6.

Fig. 9.—White ash was among the tree species most resistant to flooding. A few vigorous individuals, in less than 2 feet of water, threw trunk sprouts in 1946, during the ninth year of flooding. Two recently built duck blinds are shown in the center background. August, 1949 Yeacer: Effect of Permaxext Flooding 49

Some pin oak trees died in 1 year, and low, liackberry, privet, and huttonbush other species showed high loss at least 1 bore appreciable crops; and trees of maple, year before the time of 100 per cent mor- elm, ash, ri\er birch, and pecan produced tality. Most maples (98.9 per cent) and small crops. During the third year, wil- elms (97.1 per cent) were dead in little low, waterlocust, and waterprivet pro- more than 4 years, table 2. Survi\ing duced sparse crops and huttonbush a nor- white ash and waterlocust trees at the end mal crop. Several persimmon trees grow- of 6 years were so severely injured that ing on a steep-banked slough (Chickahom- few showed leaf in 1946. However, a in\-, fig. 2) and with root systems inun- few white ash trees showed small green dated only on the lower or stream side, trunk sprouts in October of that year. produced well in 1944. These trees died

Table 6.— .\pproximate period of flooding, up to 3 feet, required to kill all trees of various species in six study transects, Calhoun County, Illinois.

Two 50 Illinois Natural History Survey Bulletin Vol. 25, Art.

Fig. 10.—Some pecans and other trees with root collar flooded on one side but above water level on the other side died first on the flooded side.

maple, was especially noticeable in 1939 seedlings, with some stump sprouts of and 1940. Such root growth was most elm, maple, and other species. In Octo- pronounced near the new water line, but, ber, 1939, practically all of this repro-

in decreasing density, it extended down the duction except that of white ash and trunk and thus for several inches below the waterlocust showed evidence of dying; water surface. This reaction of certain in October, 1940, all was dead except woody species to the stimulus of a raised white ash in a foot or less of water. Even

water level is, of course, well known. the 4- to 6-foot ash seedlings succumbed The effect of flooding on forest repro- where flooding occurred to a depth exceed- duction was similar to that in parent trees. ing 12 or 15 inches. Of all species repre- An 8-acre clearing south of Sawmill sented, ash reproduction showed greatest Slough showed in 1938 a dense stand of tolerance to permanent flooding. —

August. 1949 Yeager: Effect of Permanent Flooding 51

TREE FALL rapid decay in this low, humid localit\, figs. 11 and 12. Falling data arc summar- Tree fall in the following discussion ized in table 7. refers to dropping well the of branches as The manner of falling in dead trees as to actual fall of the tree, wholly or in was confined to two general patterns, of part, in flood-killed timber as a result determined by the presence or absence of death, decay, wind action. and durable heart\\ood. Among the species having durable heartwood, pin oak was Rate and Manner of Falling outstanding. Although the first to succumb to flooding, pin oak was the last to Falling of water-killed trees was not fall after death. Bur oak showed rather particularly noticeable until 1941, 3 years similar characteristics. Oak branches, after the initial flooding. Prior to this particularly the larger ones, were slow time scattered trees and large branches to fall, since they contained a considerable had crashed, but this early fall was prin- \olume of heartwood. In oaks, the sap- cipalh among the numerous large, multi- wood decayed and fell usually off both branched and decadent silver maples and trunk and larger branches, leaving stand- small, badly suppressed trees of all spe- ing skeletons of heartwood. Five years cies. Many of the large maples were 4 feet or more were required for this degree of or more in diameter and some of them deca\'. Dead oaks with sound wood were probabl\- would lia\ e fallen if flooding had usually uprooted by winds rather than not occurred, fig. 3. B\' October, 1944, broken off, although in oaks weakened by falling was more or less advanced in all advanced heart rot the reverse was true. species, indicating, as would be expected. \Vaterl()cust. except for the larger trees, many of which were decadent, possessed strong heartwood and stood well. Branches of locust trees tended to fall after a year or two. White ash, with only fairly durable heartwood, and often with advanced heart rot in the larger trees, was intermediate in ability to stand.

There is a long list of rixer-bottom trees known to have quick-rotting heartwood. Most numerous of these trees on the study area were silver maple, Ameri- can elm, pecan, persiminon, sugar hackberry, Cottonwood, ri\er birch, and willow. Of these species persimmon and overmature inaple trees fell first. Multi- branched, spreading trees of all species characteristically lost their branches, leaving low, stubby, and often hollow snags. X'igorous maple, hackberry, birch, and willow trees were somewhat slower in falling, and all fell at about the same rate. Ainong species having nondurable heartwood, elm, pecan, and Cottonwood were most resistant to falling. Cottonwood \\as surprisingly durable; mature trees (lying in 1942 and possibly earlier were cut for lumber in the fall of 1944. Such trees, while having decayed sapwood, usually showed sound, though often stained, heart- Fig. 11. Silver maple wind-thrown in 1940, about 2 years after initial inundation of wood ; they had been vigorous in life; and the Calhoun County >tudy area. Photographed many of thein were 2 and some 3 or more October, In 1940. feet in diameter, fig. 13. 52 Illinois Natur.al History Survey Bulletin Vol. 25, Art. 2

Table 7.—Degree of falling in river-bottom timber on six study transects, October, 1944 and 1946, Calhoun County, Illinois.* Permanent flooding of area was begun in June, 1938. August. 1949 Yeacer: Effect of Permanknt FLooDisn 53 landed on end, becoming deeply embedded Cottonwood and willow, are constant in the soft mud bottom. Many tree sources of river driftwood. Clearing of trunks, e\en when they tell in water deep the shore lines appears to be the most prac- enough to float them, became waterlogged tical method of reducing the amount of and sank. Trees falling in shallow water. driftwood which, in navigable streams, is

Fig. 12.—Same log as in tig. 11, October, 1945. Dying in 1939 ami falling in 1940, this maple showed advanced decay and disintegration, to be expected of nondurable woods in low, humid localities in the temperate zone. unless held up by other falls, settled in an appreciable nuisance or e\en a hazard the mud. Thus, logs and tops tended to to river shippmg and also to commercial remain on or very near the site of fall, or, fishing. if dislodged, were soon caught against That few logs from Calhoun Point the thousands of trees and stubs that cov- reached the Mississippi River was due to ered the area. Comparatively few of the fact that, prior to flooding, an exten- these logs reached the Illinois and Missis- sive and thorough clearing operation had sippi rivers froin the interior of the Pere been performed along the Illinois Ri\er Marquette tract, even during the severe >hore line. Much of the Mississippi River

floods of 144.? and l')44. shore line at this point is low bluff, some- Many green or flood-killed trees that what higher than pool stage. For this have grown along the shores of navigable reason little or no tree mortality occurred streams are uprooted and swept into the from the rise in water level, and no dead main channels. Flooded, uncleared islands timber from this shore reached the river in the Mississippi River, covered mostly by channel. 54 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

^v-.

Fig. 13. —A 42-inch Cottonwood flooded about 4 inches on the lower side in 1938. It died in 1942 and was cut for lumber in 1944. The heartweod was stil! sound but stained in October, 1946.

POST-FLOODING stands had appeared in a scattered pattern SUCCESSION on most of the water areas, as well as on wooded sites (timber dead) where the General, and for the most part inci- water table approached the ground sur- dental, observations on changes in plant face, fig. 8. Stands of duckpotato (Sagit- and animal life subsequent to flooding taria spp.) were particularly abundant were recorded during the investigation. along the lower end of Big Slough, where Verj' profound changes are, of course, the channel had been deepened. Along still in progress; this report is merely a the shore lines of both the Illinois and summary of early succession phenomena. Mississippi rivers, rows of smartweed (Polygonum spp.) and cockspur or wild Plants millet (Echinochloa spp.) appeared in both mixed and pure stands, undoubtedly due The most conspicuous change in plant to the windrowing effect of wave action, life was that of death in flooded timber. fig. 16. Luxuriant growths of rice cut- At the end of 8 years, most of the dead grass ( Leersia oryzoides) developed along and fallen stand was in water less than 3 the margins of many flooded areas in 1946, feet deep. fig. 17. Conversion of much of this area, log- Water in the sloughs and lakes, back- filled and snag-studded, to marsh was to water in nature and without current except be expected, and this transition had begun that induced by the rise and fall in pool before 1946. Ecological development in levels, became progressively clearer toward the area following flooding may be the head of such bodies, even with the ini- ascribed largel\' to spread of plants already tial inundation in 1938. This condition present and to introduction of seeds b) permitted luxuriant growths of coontail or water. As early as 1938, 2 jears after hornwort ( Ceratophyliuni deinersum) and excavation, borrow pits on the east end leafy pondweed (Potamoyeton foliosus), of the area supported vigorous stands of which became very noticeable in 1939 and cattail (Typha lalifolia). By 1940, cattail reached their greatest development in August, 1949 Yeager: Effect of Permanent Flooding 55

1942. Very heavy stands of sedfjes (Carex peared by the fall of the following year. spp.) sprang up along some of the more Moist-soil species, particularly rice cut- open shiughs and shallow-water areas. grass, appeared in dense stands in 1946, The water supported a laser of duckweed probably from seed deposited by Hood

(Letinui. Jl'olffia, and Spirudela) , com- waters.

monly 1 inch thick, figs. 6 and 18. Fila- Forest reproduction, principaliv wilhjw mentous algae covered e\ery suhmerged and Cottonwood, appeared along the shore ohject, fig. 19. lines of the Mississippi and Illinois rivers E.xtreme flood conditions during the as early as 193^5, particularlv where clear- early growing seasons of 1943, 1944, and ing had been done. Growth was vigorous 1945 had a profound effect on suhmerged in 1940. These species also appeared along and most emergent vegetation. The the shore lines of the shallower and more smothering effect of muddy, silt-laden open sloughs. Seeding was of course by flood water severely decreased the stands; wind and water from numerous parent during the summer and fall of 1943 and trees still present on surrounding unflooded 1944, onlv scattered growths appeared; land. bv 1945. all the plants mentioned above On certain wet "Hats," notably north- except duckpotato virtually disappeared west of Lower Roval Lake and along part from the area, hut manv of tliem had reap- of the Illinois River shore line, silver

Fig. 14.—A silver maple stand, October, 1946, 8 years after inundation, showing falling and break-off characteristic of species having nondurable heartwood. 56 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

debris in October, 1946. Fig. 15. Silver maple "flat," flooded in 1938; a maze of fallen

the Illinois Fig. 16.— Stand of smartweed (Polygonum spp., chiefly lapathifolium) along River on Calhoun Point, October, 1941. Seed presumably "windrowed" by wave action. August, 1949 Yeager: Effect of Permanent Flooding 57

maple reproduction was abundant in Octo- ously at this time ; in some places it was as ber, 1944, reaching a density of four stems much as 10 or more feet high, fig. 20. per square foot on small areas. AVhite ash and American elm seedlings were Manimals common. Some pecan and pin oak reproduction was noted at \ arious points. By Among mammals, muskrats (Ondatra October, 1946, practically all open, un- zibelhicus zibet hiiiis) were most recep- flooded land supported a fair to full stand tive to conditions brought about by per- of river-bottom forest seedlings. Maple, manent flooding of about one-fourth of elm, ash, willow, Cottonwood, pin oak, and Calhoun Point. In a complete coverage pecan reproduction was growing vigor- of the area in Februarv, 1938, Frank C

Fig. 17.—Rice cutgrass had attained luxuriant stands along the margins of flooded woodland in the study area by October, 19+6. 58 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

Fig. 18.—Mat of duckweed an inch thick covered much of Royal Lake, Calhoun Point, Octo- ber, 1941.

Fig. 19.—Filamentous algae grew in heavy mats over every submerged object, here revealed by a 16-inch drawdown, October, 1940. August. 1949 '^'eacer: Effect of Pek.maxext Flooding 59

Fig. 20.— Willow, cottoinvooii, elm, and silver maple reproduction on mud flat following death of most of the original stand as a result of flooding that raised the permanent water level nearly to the ground surface. .-^ luxuriant stand of rice cutgrass grew between the bare mud flat and the forest zone in October, 1946.

Tr.*ppisg Season .\IisKRATS Trapped Bellrose, Jr., of the Illinois Natural His- tory Survey (personal communication) 1938-39 found no sign indicating the presence of these aniinals. In April of that year, temporary closing of the Alton Dam flooded the borrow pits and sloughs along the rivers, and within a few days muskrats appeared. Muskrat signs were fairly common on June 2, 1938, and in places abundant in October of the same year. Strong evidence was found during the next 3 >ears that muskrats were increasing in numbers. By October, 1940, muskrat icutting? (chiefly of cattails and sedges), droppings, and burrows were noted in or near practically everv slough on the area, f^K.21. The steady increase in numbers of muskrats in the Calhoun Point study area

(Yeager ^" Rennels 1943) is reflected by complete or partial counts of trappers' :atches for hve seasons, as follows: 60 Illinois Natural History Survey Bulletin Vol. 25, Art. 2 lotor) numbers during the next 2 or 3 floods reached their peaks during the years. However, this species, on Calhoun young-rearing seasons. It is therefore Point as elsewhere throughout its range, not improbable that most of the animals, showed strong recovery by 1943. The except those near the river bluffs, perished, raccoon population on the study area was during the inundation. It should be re- high in 1944. membered that, however well housed Opossums (Didelphis virginiana virgini- above the water level, any animal without tina), never heavily trapped or hunted food will find itself in dire straits before

Fig. 21.—Muskrat burrows under an old stump exposed by a drawdown of the water level of the Illinois River at Calhoun Point, October, 1940. The animals had attempted to plug entrances following exposure.

after about 1939 because of low fur prices, the end of a 2- or 3-week flood peak. remained numerous on Calhoun Point Opossums showed some indication of until 1943, when floods of that year and coming back to Calhoun Point by Octo- 1944 apparently reduced their numbers to ber, 1946, but at that time they were far a very low point. Astonishing as it may below their 1942 numbers. seem, not a single opossum track was seen Minks (Mustela vison), animals that during an inspection trip over the area are highly adaptable and equally at home that lasted from October 13 to 18, 1944, on land or in water, were affected b} the although special efforts under excellent Calhoun Point floods less than any other conditions were made to find such tracks. fur species. Signs indicating substantial No reason other than flooding can be given populations were noted during every year for the scarcity of opossums. These ani- of the study. mals are good climbers but not good swim- Both red foxes (Vulpes fulva) and gray mers, and they do not possess marked abil- foxes (Urocyon cinereoargenteus cinereo- ity to take food from water. Since the argenleus) were present on Calhoun entire point was flooded to a depth of sev- Point previous to the initial flooding in eral feet in both years, opossums there 1938. Flooding reduced the habitable were separated from land by flood waters area for both species, and the peak floods for as much as 3 miles. Moreover, the of 1943 and 1944 undoubtedly evicted August, 1949 Ycager: Effect of Permanent Fiooping 61 hem from the area. Abundant signs of rels and 4 gray squirrels. Previously, the oxes were never observed on the study two species were more nearly equal in rea after 1Q44. though fox density on numbers. djacent, but higher, areas remained at a Cottontail rabbits (Sylvilagus flurida- ery high point tor several years. iius) were notably scarce on Calhoun Striped skunks (Mephitis mephitis) Point, e\en before the 1943 and UH4 lere more numerous in 1^38 than at any floods, which undoubtedh evicted them ther time of the stud\ . E\ en in that year from the tract. They \\ere more common ens appeared to be confined to the high- along the inland boundaries of the area, st ridge— the fallow field and the woods and on adjacent farm land, a circumstance the north of the field, both east of Big to be expected in view of the ver\' low, Hough. Flooding and the resultant 3- wet nature of the greater part of Calhoun oot rise in the permanent water level Point. Both food and nesting conditions indoubtedly made the area less suitable on the study area were obviously less fa\or- or this ground-denning species. ahle than where waste grain, chners. and

Woodchucks ( .Mtiriiiotti rnoniix munax) other farm crops afforded abundant fo(jd, Iso were adversely affected by permanent and higher sites provided safer nesting loading, although along the higher ridges grounds. heir dens and other signs were fairly com- non in October of 2 vears of this studv, Birds 944 and 1946. Calhoun Point has long been a favored Succession in bird life on this tract of ocality for squirrel hunters. Until about Hooded bottomland is indicated here onh 940. gray squirrels ( Sciurus caroHnensis) from general observations. .Aquatic and iredominated, as was attested by numerous marsh species, common before 1938, had lunters. Fox squirrels (Sciurus niger rufi- become more numerous by 1944. Some

enter) , until that time, were most com- indication of the increase is reflected in non along the pin oak ridges bordering table 8, the data for which were taken he large opening in the center of the area from one 7-mile boat or canoe trip in each ind along Big Slough and the west bound- of 4 years on Big Slough, Royal Lake, iry. both territories adjoined by cultivated Chickahominy Slough, and the Illinois ields. \Vith the death of large tracts of River. The same route was followed at iooded timber and the resultant opening each observation. The general validity of ip of the stands, fox squirrels became the the data in table 8 is strengthened by a lominant species over practically the number of other trips over the tract that

•ntire area. In October, 1944, the writer \ ielded similar information. :overed every part of the 4-square-mile Calhoun Point has been subjected to ract and observed a total of 24 fox squir- heavy duck hunting since 1938. One hun-

Table 8.—Numbers of birds observed on a 7-mile water trip through Pere Marquette itudv area in each of 4 years. .

62 Illinois Natural History Survey Bulletin Vol. 25, Art. 2 dred or more blinds scattered through the of shallow water, abounding in minnows, 4-squ;ue-inile area resulted in widespread small fish, frogs, crayfish, and other food, shooting almost daily during each hunting afforded excellent foraging grounds for season. Because waterfowl were thus dis- all species of wading birds present. couraged during the fall in their attempts With the appearance of marsh, breeding to use the new marsh and flooded wood- populations of red-wing blackbirds (Age- land, evaluation of the area for water- laius phoeniceus phoeniceus) became estab- fowl purposes has been complicated. lished in 1938. On May 15, 1942, Harry However, the tract became potentially G. Anderson and the writer counted 22

more attractive to dabbling ducks in its red-wing nests in less than one-half acre f flooded state than it was formerly, because of cattail marsh in Sawmill Slough, north of the larger shallow water area and the of Coon Lake. This was near the middle

development of rice cutgrass, fig. 17, of the area ; other red-wing colonies were smartweed, fig. 16, wild millet, and other found in the various cattail stands along aquatic and moist-soil plants that furnish the Illinois River, Big Slough, and other food for ducks. places. The 10 red-wings noted on August Wood ducks (Aix sponsa) are the only 6, 1938, table 8, were in the vicinity of a wild waterfowl that nested in the area. cattail marsh at the mouth of Chickahom- Yearly observations by Frank C. Bellrose, iny Slough. Jr., and other members of the Natural Highly suitable nesting and food condi- History Survey staff indicate a severalfold tions for woodpeckers were provided by increase in breeding and summer popula- the thousands of dead trees, in every con- tions of these birds since 1938, apparently dition of decay, on Calhoun Point. An because of the greater area of attractive increase of woodpeckers on the area was habitat. Nesting sites in the hundreds of noticeable as early as October, 1939, fol-

hollow snags and trees are ample ; and lowing the death of numerous maple and quiet, duckweed-covered waters in the other trees. As listed in table 8, at least flooded timberlands are probably ideal as six species were observed, of which the red- rearing grounds. There was some evi- headed woodpecker (Melaiierpes erythro- dence in 1946 of decreasing attractiveness cephalus) was most common. Next in of the area to wood ducks as a result of numerical abundance was probably the the opening up of flooded woodland and red-bellied woodpecker (Centurus caro-

the trend toward the marsh stage of suc- linus) ; the flicker (Colaptes atiratus cession. liiteus) was third. An unusual number There was abundant evidence during of pileated woodpeckers (Ceophloeus pile- much of the study period of a general (itus abieticola) were present, the writer increase in number of herons on the area. observing 13 on the morning of October After 1941, a score or more of these birds 14, 1944. At least six were in one scat- could often be counted at a single stand, tered flock. Downy (Dryobates pube- and, by including all of the concentration sceris) and hairy woodpeckers (D. villo- areas on the point, 500 to 700 herons could sus) were other species recorded. easilv ha\e been recorded in a dav's time. No attempt was made to determine the On August 6, 1941, Harry G." Ander- effect of flooding on perching birds. Such son, an ornithologist associated with the conspicuous forms as the prothonotary Natural History Survey, and the writer warbler (Protonotaria citrea) and Amer- counted 200 American egrets (Casriiero- ican redstart (Septophaga ruticilla) were dius albus egretta), 12 snowy egrets abundant on the area in years covered by (Egretta thula thula), and 40 great blue this report. Harry G. Anderson and the herons (Ardea herodias herodias) on one writer recorded 45 of the former and 30 20-acre bay. None of these birds is of the latter on May 15, 1942. A total of included in table 8. In June, 1941, four 66 species of birds were listed on that

green heron (Butorides virescens) rooker- date, but it is certain that many of these ies, averaging 20 nests each, were found were migrants. General evidence indi- in the course of routine work. Systematic cates that the prothonotary warbler, at coverage of the tract would probably have least, increased over the population pres-

disclosed others. The 600 or more acres ent on the area is 1938. ;

\ugust, 1949 Yeager: Effect of Permanent Flooding 63

Starlings (S/urnus vuli/tiris vulyaris) the rate of dying in tree species and suc- ,vere observed in considerable numbers on cession in aquatic vegetation. he area in October, 1946. 7. The effect of flooding on timber was studied under three categories: (1) SUMMARY timber actually flooded; (2) timber on sites where the water table had been raised

1. Timber killed by impoundment of to the ground surface; and (3) timber on Aater for power development, channel unflooded land, where the average sum- mprovement, flood control, and other mer water table had been raised approxi- lurposes represents a problem of growing mately 3 feet. mportance throughout the United States. 8. Eight years of actual flooding of 2. The effect of water impoundment timber areas resulted in practically com- )n timber was studied over an 8-year plete tree mortality. In most tree species, leriod, 1939-1946, at the junction of the flooding to a depth sufficient to cover the Mississippi and Illinois rivers, where siz- root collar, less than 20 inches, was fatal. ible tracts of river-bottom timber were Rate of dying showed wide variation by cilled by the Alton Dam impoimdment, species. Pin oak was most susceptible to irst pooled in 1938. injury from flooding, all individuals of this 3. The study area, Calhoun Point, species dying before or during the third consisted of 2,200 acres of river-bottom \ear. White ash was most resistant, a rorest, sloughs, lakes, and small marshes. few individuals giving rise to trunk About 600 acres of this tract were flooded sprouts 8 years after inundation. Mortal- lermanently by the Alton Dam, which ity in most other tree species was 100 per aised the average summer water stage cent in 6 years. Waterlocust showed a ibout 3 feet. This rise in level reduced mortality of 96.0 per cent and black wil- :he highest elevation on Calhoun Point low 43.5 per cent in 6 years; a few trees from 10 to 7 feet above the a\erage sum- of these species were still alive 8 years iier water surface. after impoundment. All bur oak trees 4. Timber stands on the studs area \\ere dead 3 years after permanent flood- verc all-age, river-bottom hardwoods ing was begun ; all persimmon, hackberry, rharacteristic of the upper Mississippi hawthorn, river birch, and Cottonwood Ri\er valle\. Silver maple was easily the were dead in little more than 4 years. dominant species; American elm, white Most silver maple was dead in about 4 ish, pin oak, pecan, river birch, cotton- \ears; all silver maple, American elm, ivood, black willow, persimmon, hack- and pecan were dead in about 6 3 ears. aerry. and waterlocust were other com- 9. The three shrub (or small tree) non species. Important shrubs were but- species represented in the water sample :onbush, waterpri\et, and deciduous holly. likewise varied in tolerance to flooding. 5. The effects of flooding were studied Deciduous holly showed 100 per cent an sample areas, consisting of six 50-foot mortality in about 4 years. Waterprivet, transects, aggregating 3.5 miles in length. in October, 1946, more than 8 years after These transects crossed all representati\e flooding, showed S5 per cent mortality timber types on Calhoun Point. Indixid- sur\i\ing indi\ iduals were in less than 2 iial trees in the sample were identified by feet of water. It appeared in 1946 that numbered metal tags attached \\ith gal- some of these would li\e. Buttonbush lanized nails at breast height. Records was definitely the most tolerant species involving species, d.b.h., crown class, gen- sampled, this shrub showing a survival of eral vigor, depth flooded, and year of 40 per cent or more except when deepl.\' tieath were taken at intervals. A total submerged. af six inspections, in addition to the one 10. The diameter of trees and shrubs St time of tagging, and numerous visits at sidijected to flooding had little influence ither seasons, supplieil the data for this on their death rate. An apparent differ- 'eport. ence in the 2-inch class was due to species 6. River stages, 1937-1946, at Graf- rather than to size. In general, within on, Illinois, less than 2 miles downstream each species, healthy, vigorous trees showed rom the area, were studied in relation to the greatest resistance to flooding, and the ;

64 Illinois Natural History Survey Bulletin Vol. 25, Art. 2

very small class (other than in semiaqua- snapped off at varying distances along the tic species) and the overmature class trunk. showed the least resistance. The depth 18. Dead timber falling on the study flooded (short of submersion) likewise area became waterlogged or deeply embed- appeared to make little difference, provided ded in mud. Few falls reached the Mis- the root collar was covered. A depth of sissippi and Illinois rivers to offer hazards less than 20 inches was sufficient to cover to shipping and commercial fishing. the root collar of all species involved. 19. By 1946, conversion to marsh of 11. The harmful effect of a raised the flooded bottomland, then a jumble water table was clearly discernible, partic- of fallen logs and debris lying in mud and ularly where mud conditions were cre- shallow water, had begun. Cattail, duck- ated, but, for each species, tree mortality potato, and various sedges were the most was less severe in mud than in water. To common marsh invaders ; smartweed, wild mud, as to water conditions, pin oak was millet, and rice cutgrass held a similar very susceptible and white ash very resist- position on moist soil. ant; semiaquatic shrubs like waterprivet 20. Extremely heavy growths of coon- showed no mortality in mud. tail and leafy pondweed, often covered in 12. On land above the mud level, but the fall by a mat of duckweed, appeared subjected to a 3-foot rise in the water in the clear-water sloughs and lakes dur- table, only pin oak showed conspicuous ing the first 4 years of flooding. reaction. Here, at the end of approxi- 21. Floods, several feet above normal mately 6 years, mortality among trees of pool stage in 1943, 1944, and 1945, this species had reached 28.2 per cent and destroyed practically all submerged and was noticeably progressive. Losses in elm emergent aquatic vegetation, but, by the and maple were much lower, and white fall of 1946 several species showed evi- ash, pecan, cottonwood, and several other dence of recovery. trees and shrubs apparently were unaf- 22. Reproduction of river-bottom tree fected by the increased water level. species was common in 1944, and, in 1946, 13. Several tree species bore fruit un- seedlings of maple, elm, ash, willow, cot- der flooded conditions. This occurrence tonwood, pin oak, and pecan were grow- was most pronounced during the first 2 ing vigorously. years. Only willow, waterlocust, water- 23. Among mammals, muskrats privet, and buttonbush produced fruit dur- showed great adaptability to conditions ing the third year subsequent to inunda- induced by flooding. The severe floods tion. of 1943 and 1944, and a lesser flood in 14. Trees with root systems flooded 1945, apparently depleted their numbers, only on one side showed differential dying but there was evidence of recovery byl rates in parts of the same tree, the side October, 1946. Opossums and cottontail|i inundated being nearly always the first rabbits were apparently evicted from theI to die. area by the series of high waters. 15. Willow, white ash, and button- 24. Raccoons and minks, with some bush showed marked ability to set adven- fluctuations in populations, remained com- titious roots during the first 2 or 3 years mon to abundant in the area throughout of flooding. Silver maple showed this the period of study. ability to a lower degree. 25. Land mammals, such as wood- 16. The effect of flooding on forest chucks, skunks, and foxes, found less and reproduction was similar to that on par- poorer habitat on the area after flooding ent trees. White ash reproduction showed in 1938 than previously. The 3-foot rise by far the greatest tolerance to flood con- in the water table undoubtedly limited the ditions. area suitable for ground dens on this low 17. Falling of dead timber became flood plain. noticeable 3 years after flooding ; it was 26. Flooding improved the Calhoun advanced 6 years afterward, and e.xtremely Point habitat for wood ducks, herons, and pronounced 8 years afterward. Pin oak woodpeckers, and was attended by notice- showed greatest resistance to trunk fall able increases in the populations of these other species, without durable heartwood, three groups. The increase was perhaps, August, 1949 Yeager: Effect of Permanent Flooding 65

Tiost conspicuous in woodpeckers, for marsh was accompanied by increases in Ivhich the thousands of dead and dying the number of nesting red-wing blackbirds, trees provided unlimited food and nest- Considerable numbers of starlings were ng sites. The development of cattail obser\ed on the area in 1946.

LITERATURE CITED

Vmerican Ornithologists' Union 1931. Check-list of North .American birds, fourth edition. 526 pp. American Ornithologists' I'nion. Lancaster, Pa.

jreen. William E.

1947. Effect of water impoundment on tree mortality and growth. Jour. Forestry 45(2) : 118-20.

elsey, Harlan P., and William A. Dayton, eds. 1942. Stanilardized plant names, second edition. 675 pp. J. Horace McFarland Co., Harris- burg, Pa.

lecker, Walter L., and Donald M. Hatfield 1941, Mammals of Illinois. Chicago Acad. Sci. Bui 6(3) :17-60.

eager, Lee E., and R. G. Rennels 1943. Fur vield and autumn foods of the raccoon in Illinois river bottom lands. Jour. Wild- life Mgt. 7(1) :45-60.

Recent Publications

A.—ILLINOIS NATURAL HISTORY SURVEY BULLETIN. Volume 22, Article 1.—The Plant Bugs, or Miridac, of Illinois. By Harry H. Knq September, 1941. 234 pp., frontis. + 181 figs., bibliog., index. $1.25. Volume 22, Article 2.—Studies of North American Plecoptera, with special referenc

the fauna of Illinois. By T. H. Frison. September, 1942. 122 pp., frontis. + 126 i bibliog., index. $1.00. Volume 22, Article 6.—Survey of the Illinois Fur Resource. By Louis G. Brown and Lee E. Yeager. September, 1943. 70 pp., frontis. + 33 figs., bibliog. (Bound with: Article 7.) Volume 22, Article 7.—Illinois Furbearer Distribution and Income. By Carl O. Mohri^ September, 1943. 33 pp., frontis. + 24 figs., bibliog. (Bound with Article 6.) Volume 23, Article 1.—The Caddis Flies, or Trichoptera, of Illinois. By Herbert H,' Ross. August, 1944. 326 pp., frontis. + 961 figs., bibliog., index. $1.50. ^ Volume 23, Article 2.—Duck Populations and Kill. By Frank C. Bellrose, Jr. Novem-^ ber, 1944. 46 pp., frontis. + 27 figs., bibliog. 50 cents. V^olume 23, Article 3.—Overfishing in a Small Artificial Lake: Onized Lake near Alton, Illinois. By George W. Bennett. May, 1945. 34 pp., frontis. + 15 figs., bibliog. Volume 23, Article 4.—Wetwood of Elms. By J. Cedric Carter. August, 1945. 42 pp., frontis. + 30 figs., bibliog. Volume 23, Article 5.—Fox Squirrels and Gray Squirrels in Illinois. By Louis Q, Brown and Lee E. Yeager. September, 1945. 88 pp., frontis. + 42 figs., bibliog. Volume 24, Article 1.—The Mosquitoes of Illinois (Diptera, Culicidae). By Herbert ' H. Ross. August, 1947. 96 pp., frontis. + 184 figs., bibliog. 50 cents. Volume 24, Article 2.—The Leafhoppers, or Cicadellidae, of Illinois (Eurymelinae-j Balcluthinae). By D. M. DeLong. June, 1948. 280 pp. + 514 figs., bibliog., index, $1.25. Volume 24, Article 3.—The Bass-Bluegill Combination in a Small Artificial Lake. George W. Bennett. December, 1948. 36 pp., frontis. + 10 figs. Volume 24, Article 4.—The Pseudoscorpions of Illinois. By C. Clayton Ho£E. Jb 1949. 86 pp., frontis. + 51 figs., bibliog., index. 50 cents. Volume 25, Article 1.—Characteristics of Residual Insecticides Toxic to the House Fly^J By Willis N. Bruce. July, 1949. 32 pp., frontis. + 14 figs., bibliog. B.—ILLINOIS NATURAL HISTORY SURVEY CIRCULAR. 32.—Pleasure With Plants. By L. R. Tehon. February, 1949. (Third printing, widlj revisions.) 32 pp., frontis. + 9 figs. 34.—Rout the Weeds! Why, When and How. By L. R. Tehon. September, IS (Fourth printing, with revisions.) 47 pp., color frontis. + 13 figs. 36.—Planting and Care of Shade Trees. By J. E. Davis. September, 1947. (Tbir printing, with additions.) 28 pp., frontis. + 20 figs. 38.—^Windbreaks for Illinois Farmsteads. By J. E. Davis. February, 1949. (Thif printing, with additions by L. B. Culver.) 33 pp., frontis. + 27 figs. 39.—How to Collect and Preserve Insects. By H. H. Ross. July, 1949. 59 frontis., + 65 figs. 41.—How to Recognize and Control Termites in Illinois. By B. G. Berger. February^l 1947. 44 pp., frontis. + 32 figs. 42.—Bird Dogs in Sport and Conservation. By Ralph E. Yeatter. December, 19 64 pp., frontis. + 40 figs. G.—ILLINOIS NATURAL HISTORY SURVEY MANUAL. 2. Illinois —Fieldbook of Land Snails. By Frank Collins Baker. August, 1939. 166 pp,f color frontis. + 170 figs., 8 pis. $1.00. 3.—Fieldbook of Native Illinois Shrubs. By Leo R. Tehon. December, 1942. 307 4 color pis. + 72 figs., glossary, index. $1.25.

List of available publications, about 400 titles, mailed on request.'

Single copies of Illinois Natural History Survey publications for which no price is liitedj! will be furnished free of charge to individuals until the supply becomes low, after which ••« nominal charge may be made. More than one copy of any free publication may be obtaine^r without cost by educational institutions and official organizations within the State of IlliDoil; prices to others on quantity orders of these publications will be quoted upon request.

Address orders and correspondence to the Chief Illinois Natural History Survey Natural Resources Building, Urbana, Illinois