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Pollen analysis of a post glacial peat deposit in Vancovuer Kiss, Gyula Karoly 1961

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POLLEN ANALYSIS OF A POST GLACIAL PEAT DEPOSIT IN VANCOUVER by GYULA KAROLY KISS B . S . F . , Univers i ty of B r i t i s h Columbia, 1959 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department of Biology and Botany We accept t h i s thes is as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1961 In presenting t h i s thes is i n p a r t i a l fu l f i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y ava i lab le f o r reference and study. I further agree that permission f o r extensive copying of t h i s thes is f o r scho lar ly purposes may be granted by the Head of my Depart-ment or by h i s representat ives . It i s understood that copy-ing or p u b l i c a t i o n of t h i s thes is f or f i n a n c i a l gain s h a l l not be allowed without my wr i t ten permiss ion. Department of Biology and Botany The Univers i ty of B r i t i s h Columbia-Vancouver 8, Canada. Date September 8, 1961. i i ABSTRACT The main purpose of t h i s study i s to recon-s truct the Post G l a c i a l vegetat ional and c l imat i c changes ind icated by the p o l l e n grains and spores preserved i n the Camosun peat bog. U t i l i z i n g t h i s knowledge an a t -tempt i s made to define the approximate age of the e a r l -i e s t m i c r o f o s s i l deposits of t h i s bog by comparison of the r e s u l t s with those of Hansen (1947). A s ing le sample core was taken from the Camosun bog. The core was d iv ided into ten centimetre channel specimens, each of which was macerated using a new tech-nique. The macerated m a t e r i a l , i n c l u d i n g the microfos-s i l s were mounted on s l i d e s , and percentage frequencies were obtained for the m i c r o f o s s i l s i n each specimen. The frequency re su l t s were in terpreted and conclusions drawn on the bas is of the k ind and number of m i c r o f o s s i l s recovered. It i s concluded that the primary fores t was composed mainly of Pinus, which changed l a t e r into a f o r -est character ized by Pseudotsuga and Tsuga. Thus the c l i -mate appears to have changed from warm and dry to cooler and more moist . The approximate age of the f i r s t deposits i s defined as ranging between four and s ix thousand years . F i n a l l y various suggestions for future work are presented, i n c l u d i n g proposals f o r future studies i n the same bog, and methods for the improvement of palyno-l o g i c a l techniques i n general . i i i TABLE 03? CONTENTS Abstract i i Table of contents i i i L i s t of tables and i l l u s t r a t i o n s i v Acknowledgements v Introduct ion 1 Geography, geology and present f l o r a of the peat bog ( i ) Geography 4 ( i i ) Geology 5 ( i i i ) Present f l o r a 6 Methods 15 F i e l d c o l l e c t i o n 15 Storage 16 Laboratory methods 16 Results 22 Discuss ion 28 Interpretat ion of r e s u l t s 28 Development of the peat bog 28 Succession of the surrounding fores t 52 Cl imat ic changes 38 Age determination 40 Suggestions for future inves t igat ions 43 Summary of conclusions 47 Bibl iography 49 i v LIST OF TABLES AND ILLUSTRATIONS Text f igure I : Map showing the peat bog 9 Table I : Present f l o r a of the peat bog 10 Table I I : Present f l o r a of the immediate v i c i n i t y of the peat bog 11 Plate I 52 Plate II 54 Chart I 55-56 V ACOOWLEDGEMENTS At t h i s place I would l i k e to express my grat i tude to Dr . Glenn Everet Rouse. He was always ready to give me a h e l p f u l hand. His encouraging a t t i -tude helped me through a l l the d i f f i c u l t i e s during the preparations for and the w r i t i n g of t h i s t h e s i s . My thanks also go to Mr. 1. Magasi, Dr . V . J . K r a j i n a , Dr. W. H . Mathews, Dr. R. F . Scagel , Mr. L . O r l o c z i , Mr. G. L . l e sko , Mr. L . V . H i l l s , Mr. M. B e l l , and to the res t of the people who helped me during the preparat ion of the present t ex t . F i n a l l y , I am very gra te fu l to my wife , Janet E . K i s s , who reread and also typed t h i s t h e s i s . Her moral support was also inva luab le . 1 INTRODUCTION Within the last f i f t y years pollen analysis of post-glacial peats has become a valuable part of palae-oecological interpretations. It has provided information on climates, environmental changes, and sedimentation, and has become useful i n dating several post-glacial horizons. Pollen analysis was introduced i n the second decade of this century by Scandinavian workers(e.g. Lager-heim, von Post, etc.), and has become a rapidly growing f i e l d of science. Three names are associated with pollen analysis in the Pacific North West. Hansen (1941, 1947) was one of the earliest workers to collect useful data along the West Coast. Included i n his studies are analyses of a bog on Lulu Island and another one in New Westminster. Terasmae (1958) i s another student who has performed some palyno-logical work on Vancouver Island. He stresses the consid-erable importance of pollen analysis in geological inves-tigations and has been using i t very successfully i n Pleis-tocene studies i n Eastern Canada. Very recently a compre-hensive picture of the late-Pleistocene environments of the North Pacific regions of North America has been con-tributed by Heusser (i960), a former student of Hansen. He has collected peat samples throughout the West Coast of North America (Alaska, British Columbia, Washington, Oregon, and California) and has used the data obtained from 2 these samples to reconstruct the p o s t - g l a c i a l c l imat i c and vegetat ional changes of t h i s r e g i o n . While these pioneer workers have provided "basic evidence on p o l l e n d i s t r i b u t i o n and past c l imates , much remains to he accomplished i n Western North America, p a r t i c u l a r l y i n the i n t e r i o r regions of B r i t i s h Columbia. Previous inves t igators have given valuable information on gross c l imat i c changes, but have contributed l i t t l e con-cerning more l o c a l i z e d c l i m a t i c and environmental succes-s ions . In a d d i t i o n , almost nothing has been presented about land-water r e l a t i o n s h i p s at d i f f e r e n t i n t e r v a l s i n the p o s t - g l a c i a l succession. As a small beginning contr ibut ion to the l a r g e r problem the present i n v e s t i g a t i o n was i n i t i a t e d on a bog i n Vancouver, B . C . , with a t h r e e - f o l d objec t ive : ( i ) to invest igate the record of p lants i n a l o c a l i z e d peat deposit with the a id of p o l l e n ana lys i s ; ( i i ) to i n t e r p r e t from ( i ) the general c l i m a t i c changes that have occurred since the f i r s t depos i t ion o f peat; ( i i i ) to invest igate the l a n d -water r e l a t i o n s at various stages i n the development of the bog. In the past, many botanists have not paid much a t t ent ion to the mutual r e l a t i o n s h i p s of tree species and herbaceous p l a n t s . This neglect was probably why ear ly palaeobotanists disregarded the importance of non-arboreal po l l en grains and spores, and based t h e i r i n t e r -pretat ions almost completely on tree po l l en g r a i n s . 3 However, modern palynolog is t s are beginning to r e a l i z e that since the environment of a given place i s charac-t e r i z e d by the as soc ia t ion of a l l p lants , and not by tree species alone, a l l the p o l l e n grains must be taken into cons iderat ion i n order to obta in comprehensive r e -s u l t s . In the present study, a l l the spores and po l l en grains have been considered i n the i n t e r p r e t a t i o n of r e s u l t s , i n keeping with the modern trend. 4 GEOGRAPHY, GEOLOGY AND PRESENT FLORA OF THE PEAT BOG ( i ) Geography: The Camosun peat hog i s located i n the c i t y of Vancouver, B r i t i s h Columbia (123i°W, 4 9 i ° N ) on the Point Grey peninsula , which projects westward and i s bounded by the Fraser River on the south and Burrard In-l e t on the nor th . I t i s one of the northern representa-t ives of the West Coast's peat deposits , but i s small i n extent compared with other bogs to the south. The present boundaries of the bog cannot be determined exact ly , because the bog and i t s ent ire v i c i n i t y have been d i s turbed . The south and east boundaries are occupied by houses, and gardens are being c u l t i v a t e d on the d r i e r p a r t s . A road and high voltage l i n e s cut through the o r i g i n a l bog, and these disturbances r e s t r i c t the i n -ves t igator i n def in ing the prec ise l i m i t a t i o n s . Neverthe-l e s s , the p o s i t i o n of the peat bog can be given by r e f e r -ence to some geographical boundaries: 16th Avenue on the north; Crown Street on the east; King Edward Boulevard on the south, and Imperial Road on the west. The area enclosed between those four roads i s approximately 0.25 square mi les . However, the edges of th i s area are not wi th in the peat deposi t . The shape of the bog i s an elongated e l l i p s e . I ts length i s about 800 yards and i t s width i s about 200 yards . The o r i e n t a t i o n of i t i s north-south. A sketch map showing the l o c a t i o n of the peat-bog i s presented on 5 p. 9 (Text f igure I ) . The present condi t ion of the hog ind icates that i t i s "being gradual ly destroyed by man's encroach-ment. The east and south ends are drying out. This area has been used as a garbage dump. The l a t t e r use of the bog i s forbidden at present . Some of the d r i e r peat has been taken away by the surrounding res idents for use as a garden f e r t i l i z e r . However, a large part of the bog i s s t i l l ac t ive and swampy, and i s occupied by t y p i c a l bog vegetat ion. ( i i ) Geology: The whole area i s part of the Point Grey form-a t i o n , which i s i n t e r g l a c i a l . Johnston (1923) defined the uppermost l ayer of t h i s formation as fo l lows: "The upper part of the sect ion i s , i n most places , t y p i c a l boulder c lay or t i l l , which i s usua l ly only s ix to ten feet th ick but thickens towards the inner end of the peninsula ." This boulder c lay i s under la in by s t r a t i f i e d deposi ts . "The upper and greater part of these deposits consis ts of sands and gravels and some s i l t . . . They are unweathered and without f o s s i l s , and are probably g l a c i a l outwash." Armstrong (1956) mapped t h i s area and described i t as " . . . sandy to s i l t y t i l l and minor s u b s t r a t i f i e d d r i f t up to s i x t y feet th ick but general ly l e s s than twenty feet , o v e r l a i n i n most places by glacio-marine clayey s i l t , s i l t y c lay , and sand, up to twenty-five feet th ick but 6 general ly l e ss than ten feet ." Thus i t may be concluded that the o r i g i n a l depos i t ion of peat occurred on s i l t y c lay which or ig inated as a post g l a c i a l marine depos i t . The sample taken from the bottom layers of the peat bog i s composed of b l u i s h -gray s i l t y c lay , with very poorly preserved m i c r o f o s s i l s and organic fragments, and contains no carbonates. This c lay i s i d e n t i c a l to c lay from the Burnaby Lake peat bog which has been found to. contain marine s h e l l s . The higher surroundings are composed of g l a c i a l outwash over ly ing t i l l , with minor amounts of g r a v e l l y sands and sands. According to Dr. W.H. Mathews (personal com-munication, June, 1961) the cav i ty i n which the peat de-pos i t s occurred i s part of one of the g l a c i a l grooves produced by the i ce sheet of the l a s t g l a c i a t i o n . The o r i -entat ion of these p a r a l l e l grooves i s general ly north-south . ( i i i ) Present f l o r a : The present f l o r a of the bog i s very t y p i c a l of peat bog vegetat ion. In undisturbed areas, the f l o r a i s composed of Pinus contorta , Tsuga heterophyl la and a few representat ives of Sorbus s i t chens i s i n the tree l a y e r . Ericaceous plants inc lude Ledum, Vaccinium, Kalmia, and G a u l t h e r i a . The herbaceous plants inc lude Rubus chamae-morus, Pteridium aquil inum, Carex spp. , grasses and bryo-phytes. This vegetat ion, however, has been a l t ered 7 r a d i c a l l y i n some places by the removal of trees and shrubs, p a r t i c u l a r l y where the high voltage l i n e s have been b u i l t . One l i n e extending from 16th Avenue to the south d iv ides the bog lengthwise, approximately i n l i n e with the p r o j e c t i o n of Camosun Street . The other t rans -mission l i n e does not a f fec t the bog very much, as i t cuts across the south end of the Jbog (project ion of King Edward Avenue), and cuts o f f only a small part of i t . Since the trees are miss ing, the cleared s t r i p s on the peat bog dry out very q u i c k l y , and the o r i g i n a l vegetation can re turn only very s lowly. The plants growing on these s t r i p s are mainly Rubus chamaemorus, Ledum groenlandicum, Vaccinium o v a l i f o l i u m , Vaccinium oxycoccus, Juncus spp. , and bryophytes. At some places , Pteridium aquilinum grows i n substant ia l stands. A complete l i s t of the f l o r a i s given on page 10 (Table I ) . The f l o r a of the immediate v i c i n i t y of the bog was also s tudied, and the l i s t of the plants i s presented on pages 11-14 (Table I I ) . Although the whole area has been disturbed by man, regeneration does not fol low the same pat tern i n a l l regions of the bog. Trees are being regenerated on the western, southern, and on part of the northern borders . The eastern part plus the remainder of the northern border i s regenerating only shrubs and herbaceous plants because of permanent dis turbances . The fores ts are composed of Thuja p l i c a t a , Tsuga he terophyl la , Pseudo-8 tsuga menz ies i i , Abies grandis , Acer macrophyllum, Alnus  rubra , .Prunus emarginata, and S a l i x spp. Broad-leaved trees occur i n s u r p r i s i n g l y large numbers a l l around these young regenerating f o r e s t s . The shrub layer i s composed of the seedlings of the above mentioned trees plus Rubus spp . , Gaulther ia sha l lon , Sambucus pubens, and Vaccinium  spp. These shrubs and the herbaceous plants Lys ichi tum, V i o l a , Pter idium, e t c . , are not very abundant under the tree l a y e r . Apparently t h i s i s because the forest canopy i s quite dense and the shade does not allow f o r optimum growth of the plants of the lower l a y e r s . On the eastern and part of the northern sides there are only a few i n d i v i d u a l trees of Alnus , Betula , and S a l i x . The res t of the vegetat ion i s composed mainly of shrubs of Rubus, Ribes , Sarothamnus, Sambucus, e t c . , and herbaceous plants (see Table I I ) . An i n t e r e s t i n g f ind in g i s that near the garbage dumps, some c u l t i v a t e d plants can be found mixed i n with the nat ive p lants , e .g . Quercus and Aesculus . These have been obviously introduced by l i t t e r of parks and gardens. 9 T E X T - F I G U R E I.: M a p s h o w i n g t h e p e a t b o g . University Endowment Lands N 4 O 15 . 16 . 1 7 _ I 8 19 _ 2 0 _ 2 I . 2 2 . 2 3 2 4 . 2 5 2 6 2 7 . 2 9 . 3 0 LEGEND Soale: one inch equals approximately IOOO feet I i i i i I 0 500 yards 2 3 Avenues o High voltage line City boundary Approximate outlines ot peat bog. Sampling 10 TABLE I Present f l o r a of the peat hog. Trees: Pinus contorta Loud. Isuga heterophyl la Sarg. Sorbus s i t chens i s M. Roem. Shrubs and herbaceous p l a n t s : Ericaceae; Gaul ther ia sha l lon Pursh. Kalmia p o l i f o l i a Wangenh. Ledum groenlandicum Oeder Vaccinium m y r t i l l o i d e s Michx. Yaccinium o v a l i f o l i u m Bong. Yaccinium oxycoccus v a r . intermedium Gray. Yaccinium parv i fo l ium Smith Yaccinium uliginosum L . Juncaceae; Juncus spp. L . Rosaceae; Rubus chamaemorus L . Perns; Mosses: Pteridium aquilinum Kuhn Bryum spp. C a l l i e r g o n e l l a schreberi (Bry. E u r . ) Grout Dicranum scoparium Hedw. Sphagnum spp. 11 TABLE II Present f l o r a of the immediate v i c i n i t y of the peat bog. Trees: Abies grandis L i n d l . Acer macrophyllum Pursh. Alnus rubra Bong. Betula papiryi'era o c c i d e n t a l i s (Hook.) Sarg. Picea s i t chens i s (Bong.) Carr . Prunus emarginata (Dougl.) Walp. Pseudotsuga menzies i i (Mirb. ) Franco S a l i x hookeriana Barrat t S a l i x l a s i a n d r a Benth. (also shrub) Thuja p l i c a t a D. Don. Tsuga heterophyl la Sarg. Shrubs and herbaceous p lan t s : Amaranthaceae; Amaranthus sp. Araceae; L y s i c h i t o n camtschatensis ( L . ) Schott Boraginaceae; Myosotis sp. C a p r i i o l i a c e a e ; Sambucus sp. Caryophyllaceae; Saponaria o f f i c i n a l i s L . S t e l l a r i a media C y r i l l 12 TABLE II (continued) Compositae; Artemis ia sp. : Sonchus asper (L.) H i l l Bidens t r i p a r t i t a L . Cirs ium edule Nutt . Taraxacum o f f i c i n a l e Webber Convolvulaceae; Convolvulus sp. Cruc i ferae; Barbaraea sp. Capse l la bursa-pastoris Medic. Cyperaceae; Carex spp. 2Scirpiialmigji<K;arpua Pre s l . Ericaceae; Gaul ther ia sha l lon Pursh. Vaccinium spp. Geraniaceae; Erodium sp. Gramineae; Agros t i s sp. Alopecurus pratens is L . Bromus sp. D a c t y l i s glomerata L . Elymus sp. Holcus lanatus L . 13 TABLE II (continued) Lolium perenne 1 . Poa annua L . Poa pratens is L. G u t t i i e r a e ; Hypericum perforatum L . Juncaceae; Juncus spp. Labiatae; Lamium sp. Mentha sp. Leguminosae; Medicago sp. Sarothamnus scoparius Wimm. T r i f o l i u m spp. Onagraceae; Epilobium angust i fo l ium L . Plantaginaceae; Plantago lanceo la ta L . Plantago major L . Polygonaceae; Polygonum sp. Rumex ace tose l l a L . Primulaceae; A n a g a l l i s sp. Ranunculaceae; - Ranunculus repens L . 14 TABLE II (continued) Rosaceae; Rubus p a r v i f l o r u s Nutt . Rubus s p e c t a b i l i s PursJa. Spiraea doug las i i Hook. Saxifragaceae; Ribes spp. Perns and fern a l l i e s : Athyrium f i l i x femina ( L . ) Roth. Equisetum spp. Pteridium aquilinum Kuhn Mosses: Gamptothecium lutescens (Huds.) Bry . Eur . Dicranum spp. Eurhynchium sp. Hypnum sp. Mnium spp. Polytrichum sp. Rhytidiadelphus sp. 1 5 METHODS F i e l d c o l l e c t i o n : In c o l l e c t i n g the peat samples, i t was con-sidered important to choose an appropriate time of year to avoid pollen and spore contamination from the a i r . Late autumn seemed to be a very good time because no plants appeared to be producing pollen or spores. Ac-cordingly, the middle of November, 1959, was chosen f o r taking samples. The sampling s i t e was chosen to afford both ease of approach and supposedly good representation of the peat i n the bog. A sat i s f a c t o r y s i t e was found ap-proximately 175 yards west-northwest of the corner of Crown Street and King Edward Avenue. The s i t e i s un-disturbed, and i s s u f f i c i e n t l y distant from the road and the small intermittent stream to escape any major con-tamination. The sample was taken with the aid of a peat borer. This peat borer, made by Djos company of Sweden, i s composed of a boring head, a sampler (50 centimetres long), and a handle. The length of the borer i s 150 centimetres and i t has three extensions, giving a t o t a l length of 600 centimetres. Every 50 centimetre length i s marked on the extensions. In- using the borer, one has to bore down to the 50 centimetre mark. The sampler i s then opened by turning the borer i n the opposite d i r e c t i o n . 16 This a c t i o n peels o f f a s t r i p of peat from the edges of the hore ho l e . The borer i s pu l l ed from the ho le , and the core i s removed, catalogued, and s tored. The same procedure i s repeated at i n t e r v a l s of 50 centimetres and the samples are kept i n consecutive order . Twelve 50 centimetre cores were taken which represent 600 centimetres i n depth. The i n d i v i d u a l cores were stored i n a wooden box and were separated from each other by means of wood. The tops and bottoms of the samples were marked so they would not be confused. The box was then covered to avoid l a t e r contamination. Storage; The c o l l e c t e d peat was not used for several months and was placed i n a dry room for storage. During storage, the peat dr ied and shrank from 600 centimetres to 400 centimetres (2/3 of o r i g i n a l l ength) . This shr inking was considered when d i v i s i o n s of the core were made f o r maceration. Laboratory methods: The maceration of the mater ia l was c a r r i e d out during the summer of I960. The laboratory techniques s tarted with the d i v i s i o n of the o r i g i n a l 50 centimetre cores into specimens. Since there were no s t r u c t u r a l l ayers to fol low i n d i v i d i n g the cores , they were divided a r b i t r a r i l y . The length selected for the i n d i -17 victual specimens was chosen at 10 centimetres. However, because the peat shrank during dry ing , the f i n a l length of each specimen was about 6.6 centimetres. Each s p e c i -men received the core symbol K-j_ and a number showing i t s place i n the successive order (e .g . K]_-l; top l ayer ; Ki~2, second l a y e r ; e t c . ) . F i n a l l y the specimens were cut in to two halves v e r t i c a l l y , and one of the halves was used f o r maceration. The maceration was i n i t i a t e d by breaking the peat in to approximately one mi l l imetre p ieces . The bro-ken peat was trans ferred to p l a s t i c beakers. These beakers were placed i n b o i l i n g water so t h e i r contents could be kept at a constant temperature (212 ° F ) . Usual ly four samples were macerated at the same time, and a l l the beakers were c a r e f u l l y l a b e l l e d to avoid mixing of spe-cimens. The maceration was performed by the combin-a t ion of two methods; the a c e t o l y s i s , and Schulze's so lu t ion methods. The ace to lys i s method was f i r s t described by Erdtman (1943, p . 2 9 ) . The macerating so lu t ion i s com-posed of concentrated s u l f u r i c ac id (one uni t ) and acet ic anhydride (nine u n i t s ) . F i f t y cc . of th i s so lu t ion are appl ied to each sample and the beakers are kept i n b o i l -ing water f o r t h i r t y minutes. A f t e r t h i s treatment the mater ia l i s centr i fuged, washed i n water three times and treated with a 5f° so lu t ion of potassium hydroxide. The 18 a l k a l i i s appl ied to d isso lve the ox id ized organic mater-i a l . Then the mater ia l i s centri fuged again and washed three times i n hot water. Af ter a f i n a l centr i fug ing , samples are mounted on microscope s l i d e s . The s ta in ing i s done with sa fran in , and corn syrup i s used to a f f i x the mater ia l to the s l i d e s . The res t of the samples are saved for reference mater ia l i n case repeated maceration becomes necessary. Af ter checking the prepared s l ides under the microscope i t was found that the s l i d e s contained a large amount of organic debr i s , and a great number of the micro-f o s s i l s were s t i l l covered with organic a t t r i t u s . There-fore another method had to be sought i n order to obtain better r e s u l t s . The method f i n a l l y selected was one em-ploying Schulze's so lu t ion (concentrated n i t r i c ac id and potassium chlorate) as the ox id i z ing agent. This proce-dure has been used by former inves t igators to macerate coa l , but to the author's knowledge, has not been appl ied to peat . In t h i s modified process, Schulze's so lu t ion was appl ied to peat which had been previous ly macerated by the ace to ly s i s method. The Schulze's so lu t ion i s a mixture of f ive grams of potassium chlorate and 50 cc . of concentrated n i t r i c ac id made up to 100 cc . with d i s -t i l l e d water. F i f t y cc . of Schulze's so lut ion was appl ied to the samples for two hours. Af ter t h i s t r e a t -ment the material v/as washed, and potassium hydroxide 19 was appl ied to d i s so lve the oxidized organic m a t e r i a l . Af ter a f i n a l washing, the samples v/ere again centr i fuged, and the m i c r o f o s s i l sediment was mounted on microscope s l i d e s . The r e s u l t s were much better than the ace to ly s i s method alone. The concentrat ion of m i c r o f o s s i l s was much higher and the s l ides were c l e a r e r . At a depth of 54-0 centimetres s i l i c e o u s matter and c lay appeared to be mixed with the peat. Therefore the samples were treated with hydrof luor i c ac id for about twelve hours to d isso lve the mineral mat-t e r . A f t e r the ac id had been discarded, the sample was washed several times with water, followed by the a p p l i -ca t ion of the ace to lys i s and n i t r i c ac id methods. M i c r o f o s s i l s recovered from each macerated sample were mounted on three or four s l i d e s and the s l ides were l a b e l l e d . The l a b e l s received the core symbol K]_, the sequence number (e .g . 1, 2, e t c . ) and a small l e t t e r to mark the s l i d e . The s l ides were then placed i n a cabinet to await i d e n t i f i c a t i o n and frequency counts. The next step of the laboratory work was the i d e n t i f i c a t i o n and frequency counts of the po l l en grains and spores. I d e n t i f i c a t i o n required pre l iminary study of the po l l en grains of the present ly growing species , and p o l l e n on modern reference s l ides provided p o s i t i v e i d e n t i f i c a t i o n s for most genera. In some cases i t was impossible to i d e n t i f y the genus due to the s i m i l a r i t i e s of several genera. These p o l l e n grains and spores 20 received only t h e i r family names (e .g . Ericaceae , Legumin-osae, e tc . ) Species were seldom i d e n t i f i e d due to close resemblance of several species . I d e n t i f i c a t i o n s were made as fo l lows: ( i ) a l i s t was made of the present ly growing p lants ; ( i i ) s l i d e s of p o l l e n of extant general were checked; ( i i i ) notes on the morphology and a draw-ing of the general appearance were made for each species of p o l l e n . A f t e r the pre l iminary studies were f i n i s h e d , a systematic frequency count was made of each 10 c e n t i -metre specimen. Approximately two hundred m i c r o f o s s i l s were counted and i d e n t i f i e d from each sample. The counts were performed using the h igh-dry object ive ( x 4 5 ) , and by travers ing the length and breadth of each s l i d e . At l eas t two s l i d e s of each sample were used for each f r e -quency count i n order to increase the p r o b a b i l i t y of i n -tercept ing a l l species present . In most cases, however, there were more than enough m i c r o f o s s i l s on one s l i d e to complete the 2 0 0 - g r a i n quota. A representat ive po l l en gra in or spore of each species was photographed and the co-ordinates r e -corded. These were chosen as representat ive types for future reference . These photographs are presented i n Plate I . I t was found that 57 samples could be used for frequency counts; the lowest three samples contained no i d e n t i f i a b l e m i c r o f o s s i l s . 21 Frequencies of genera—or f a m i l i e s , i n some cases—are expressed as percentages, and recorded on a p o l l e n diagram (Chartl(). The ordinate gives the depth i n centimetres and the abscissa expresses the r e l a t i v e percentages of the various m i c r o f o s s i l s . Frequencies of some genera are not recorded on t h i s diagram because they occur i n very low percentages (Ufa or l e s s ) . The l i s t of genera occurr ing i n low numbers i s presented on the same pages as the po l l en diagram (Chart I ) . 22 RESULTS In presenting the r e s u l t s i t should be emphasized that t h i s study i s based upon one sample core . Therefore ne i ther the r e s u l t s nor the in terpre ta t ions caji be used as representat ive for the whole bog u n t i l some a d d i t i o n a l cores are taken from various parts of the peat bog. I f the ana lys i s of other cores should give s i m i l a r r e s u l t s the conclusions could be expanded, and a f a i r l y complete p ic ture for the f l o r a l sequences obtained. Therefore the r e s u l t s and the conclusions given i n t h i s d i s s e r t a t i o n are v a l i d only f o r that par-t i c u l a r part of the peat bog which i s represented by the core . Nevertheless, the vegetat ion of the surrounding forests i s probably represented as we l l i n t h i s spot as anywhere else i n the bog. The r e s u l t s of the ana lys i s show a c l ear p ic ture of the var ious occurrences and.frequencies of the d i f f eren t genera or fami l i e s (Chart I ) . The bottom layer of the sample at a depth of 570 centimetres was composed mainly of s i l t y c l a y , with some peat mixed into i t . This layer contained the f i r s t i d e n t i f i a b l e micro-f o s s i l s . As the chart shows, the most abundant species i s P inus , followed by Alnus , P icea , and smaller percent-ages of Abies and Quercus. Only one herbaceous p lant , Typha, appears i n not iceable percentage. Noteworthy i s the complete absence of Pseudotsuga, Isuga, Ericaceae , 23 and a l l but one of the herbaceous plants. At approximately the 540 centimetre l e v e l , L arix enters the spectrum, but never reaches a high frequency; i t al t e r n a t e l y disappears and reappears at higher l e v e l s i n the core. Nymphaeaceae, Juncaceae, and Cyperaceae are also represented at t h i s depth. Tsuga shows a low percentage but soon disappears again. Except f o r some minor changes, such as the l i m i t e d appearance of Gramineae and Leguminosae, essen-t i a l l y the same pollen occurs up to 480 centimetres. At the 480 centimetre l e v e l some r a d i c a l changes completely a l t e r the f l o r a l picture. The absence of Pinus, Picea, and Abies i s s t r i k i n g l y obvious. Twenty centimetres higher, at the 460 centimetre l e v e l Pinus and Picea reappear but i n much lower percentages, while the reappearance of Abies does not occur u n t i l l a t e r at approximately 430 centimetres. At approximately the 470 centimetre l e v e l , Pseudotsuga and Tsuga appear f o r the f i r s t time. Both species are i n very low percentages at the beginning (470 centimetres) but Pseudotsuga rap i d l y increases (maximum at 370 centimetres) u n t i l at higher l e v e l s i t begins to decrease. The most recent l e v e l s of the core have yielded a very low percentage of Pseudotsugaj approximately 5$. Tsuga shows a dif f e r e n t picture, s t a r t i n g with a low percentage and slowly increasing, u n t i l at the present time i t i s quite abundant, approx-24 imately 11%. In b r i e f , i t appears that Pseudotsuga has been decreasing while Tsuga has been increas ing i n f r e -quency during the l a t e s t periods of depos i t ion . Ericaceae f i r s t appear at the 480 centimetre l e v e l and continue with only one i n t e r r u p t i o n throughout the rest of the core sample. I t i s s i g n i f i c a n t to note the very high per-centage of nymphaeaceous po l l en at the 460 centimetre l e v e l . This i s followed by a great reduct ion of both typhaceous and nymphaeaceous p o l l e n u n t i l the 260 cen-timetre l e v e l i s reached. The l a s t record of Quercus was obtained at the 430 centimetre l e v e l . At the same time Pseudotsuga was increas ing f a i r l y r a p i d l y , to become a co-dominant with Alnus at the 410 centimetre l e v e l . The same r e l a -t i v e percentages ex i s t to about 270 centimetres, with only minor changes; e .g . the sudden occurrence of r e l a -t i v e l y large amounts of Pteridium and Sphagnum between the 380 and 350 centimetre l e v e l s . At higher l e v e l s i n the core, the f i r s t major change i s the appearance of a large amount of Lycopodium at 270 centimetres. This i s followed short ly by f a i r l y large frequencies of Typha at 260, and Nymphaeaceae at 240 centimetres. Lycopodium increases i n one l ayer (240 centimetres) close to 20%, but soon disappears; the l a s t l a y e r to contain more than 1% i s the 230 centimetre l e v e l . At about t h i s l e v e l Pinus becomes more abundant at higher 25 l e v e l s i n the core . The next important change i s the complete and f i n a l disappearance of Typha at 180 centimetres. This i s followed by the disappearance of Nymphaeaceae at 130 centimetres. In the same l a y e r , Ericaceae begin to i n -crease and from there up remain at a r e l a t i v e l y high frequency inc lud ing the most recent peat specimen. There are a few genera which must be discussed separately because they could not eas i ly be f i t t e d into the above d i s cus s ion . These .'genera-, are Alnus , Abies , Betula , Juncus-Carex group, Sphagnum, and Artemis ia . Alnus i s i n r e l a t i v e l y very h igh percentages throughout the ent ire core, and the changes from high to low frequencies are very sudden. In the bottom layers (570 to 520 centimetres) Alnus i s not conspicuously abun-dant. I t increases , however, to 66$ at 470 centimetres, and decreases rather s t ead i ly to a low of 12$ at 370 centimetres. From there, i t r a p i d l y increases again, and reaches the highest of a l l the recorded m i c r o f o s s i l percentages of over 80$ at 330 centimetres. This i s followed by a gradual decrease to a minimum of 15% at 220 to 230 centimetres, another increase to 55$ at 180 centimetres, and a f i n a l decrease toward the 20$ i n the most recent l a y e r . Abies does not show any s i g n i f i c a n t trends i n the p r o f i l e . I t s tar t s i n the bottom layer i n a low percentage, occurs i n low frequency from 480 to 430 26 centimetres, and again from 250 to 150 centimetres. The l a s t trace of i t can be noted at 140 centimetres. The highest percentage reached by Abies never exceeds 6fo, Betula i s represented only i n very low per-centages of mostly l e s s than one percent . In the l a s t l a y e r , however, i t s frequency i s c lose to 2$. The Juncus-Carex combination could not be separated because the p o l l e n grains of Juncus s h r i v e l and crumple during a c e t o l y s i s , and thus become d i f f i c u l t to d i s t i n g u i s h from those of Carex. Because both genera inhabi t the same general h a b i t a t s , the i n a b i l i t y to d i s -t ingu i sh grains of each does not detract from using them for eco log ica l i n t e r p r e t a t i o n s . They f i r s t appear at 540 centimetres and, except for the i n t e r v a l between 470 to 420 centimetres, they appear continuously throughout the sample at approximately 10$ frequency. The only time they increase conspicuously i s between 120 to 70 c e n t i -metres, where t h e i r highest frequency. exceeds 30$ (at approximately 100 cent imetres) . Sphagnum does not seem to be very important i n t h i s core, and i t I s . p o s s l b l e r that the Camosun bog i s not a Sphagnum-peat bog. However, Sphagnum i n some areas produces sporangia very in frequent ly , even i n extensive bogs (Dr. W.B. Schof ie ld , personal communication). In e i ther case, i t i s vvery apparent that Sphagnum spores are not found i n large amounts. At only three places do they appear i n s i g n i f i c a n t amounts, at 380 to 350 c e n t i -27 metres, a short i n t e r v a l from 230 to 220 centimetres, and at 20 centimetres with a very high frequency of over 20$. Artemis ia occurs sporad ica l ly only i n lower l e v e l s and at low frequencies , except for one l e v e l at 440 centimetres where i t reaches a value of approximately f i ve percent. During the frequency count i t was not iced that some of the specimens contained fragments of char-c o a l . These specimens were at l e v e l s 190, 200 and 290 centimetres. Another noteworthy discovery was the appearance of large amounts of f ine sand i n specimens from 240 to 270 centimetres. During maceration, the sand se t t l ed to the bottom of the centrifuge tubes before centr i fug ing , and hence was easy to remove. F i n a l l y the occurrence of diatom she l l s should be mentioned. Diatom s h e l l s d id not occur i n the bottom layers up to 540 centimetres, probably because the spe-cimens had been macerated with hydrof luor i c a c i d which would disso lve these s h e l l s . However, specimens from 540 to 130 centimetres contained many diatom s h e l l s . At the 13Q centimetre l e v e l , diatom s h e l l s disappeared and never again reappeared. 28 DISCUSSION Interpre ta t ion of r e s u l t s : From the r e s u l t s of the ana lys i s of the peat bog i t i s poss ib le to make several suggestions concerning the development of the bog, the vegetat ional changes of i t s surroundings, and the approximate time of the f i r s t occurrence of m i c r o f o s s i l s . Development of the peat bog: Considering the p o l l e n data of the peat sample, i t i s very l i k e l y that the peat bog has developed from a l a k e . Many facts seem to support th i s p o s s i b i l i t y . The f i r s t and very i n t e r e s t i n g impression on a t tent ive study of the p o l l e n p r o f i l e s (Chart I) i s the lack of p o l l e n grains of herbaceous plants i n the ear ly part of the p r o f i l e . The only herbaceous genus occurr ing — i n small amounts—is Typha. The explanation of t h i s i s the fact that the lake i t s e l f probably did not have any vegetat ion except for a few i n d i v i d u a l s of Typha grow-ing i n the shallows. Considering Soo's (1953) c l a s s i f i c a t i o n of lakes , t h i s lake could have been i n the eutrophic stage. This stage i s character ized by the ample populations of algae and plankton due to r ichness i n n u t r i e n t s . The water of such lakes i s usua l ly t u r b i d , greenish, and neutra l or s l i g h t l y b a s i c . When the depth of the v/ater 29 becomes s u f f i c i e n t a large number of water-plants inhabit the lake. These plants are usually certa i n members of Typhaceae followed by Nymphaeaceae, Haloragidaceae, Naja-daceae and some of the Cyperaceae (Carex). A l l these hypothetical requirements are s a t i s -f i e d i n the Camosun bog, as shown by the chart and the r e s u l t s which were discussed previously. The presence of large amounts of diatom s h e l l s (page 27) suggests that there was a prosperous population of plankton. Accor-ding to Dr. R.F. Scagel (personal communication, 1961) the presence of diatoms indicates neutral or s l i g h t l y basic chemical conditions and also the presence of l i g h t . This type of environment i s also very favourable f o r water-plants. The lake hypothesis i s further supported by the appearance of representatives of Nymphaeaceae a nd by the expansion of Typha at 530 centimetres. The f i l l i n g up of the lake appears to have proceeded rapidly with the a i d of organic material from such plants. Typha gradually disappears and for a period, members of Nymphaeaceae dominate, but the s i t u a t i o n suddenly changes at the 440 centimetre l e v e l . At t h i s l e v e l the water-plants completely disappeared, which could mean one of two things: one i s that the lake became a peat bog, with an accompanying change from water to t e r r e s t r i a l plants. This i s most l i k e l y a wrong conclusion, as the samples are s t i l l f u l l of remains of diatom s h e l l s . 30 Al so , the increase i n the percentage of t e r r e s t r i a l bog plants i s not extensive, and hence does not support t h i s conc lus ion . The other, and more p l a u s i b l e , explanation i s that f or some reason the water l e v e l of the lake rose considerably , which prevented the water-plants from con-t inu ing t h e i r existence. This r i s i n g of the water l e v e l could have been caused by a change i n the course of a stream. Such a s h i f t of stream course would have sup-p l i e d the lake with a d d i t i o n a l water. Another p o s s i b i l i t y i s that a stream which had served for carry ing away the excess water of the lake was blocked by some obstac le . The t h i r d p o s s i b i l i t y i s a combination of the two, which could cause an enormous change i n the water l e v e l of the l a k e . This second deep-water condi t ion of the lake probably existed f o r quite a long time, as the r e s u l t s suggest. A few i n d i v i d u a l s of Typha were s t i l l growing i n the shallows but otherwise the lake was without vegetat ion. This condi t ion changed quite r a p i d l y at ap-proximately 270 centimetres. The sediments of sand (as reported on page 27) hastened the f i l l i n g of the l a k e . The presence of a large number of Lycopodium spores can probably be explained by t h i s same phenomenon. I t i s poss ible that a stream, prev ious ly non-existent , s tarted feeding the lake carry ing sand and organic mater ia l into 31 i t . This stream could have been the transport ing agent f o r the lycopodium spores. These p l an t s probably grew on the banks of the stream. At any rate the depth of the lake became s u f f i c i e n t f o r water-plants again at approximately the 260 centimetre l e v e l , and Typha followed by Wymphaeaceae inhabited i t s waters again. The f i l l i n g of the lake proceeded r a p i d l y thereaf ter . The lake remained as a lake for a period of time, and apparently became swampy at about 130 cent-imetres as evidenced by the prevalence of Juncus-Carex. Ericaceae also s tarted to take over the newly exposed land surface . This stage of lakes , just before they become peat bogs, i s c a l l e d the dystrophic stage (Soo, 1953). Such lakes are usua l ly developed from eutrophic lakes by the accumulation of organic a c i d s . As a, r e su l t of t h i s accumulation, the water becomes poor i n calcium and other mineral n u t r i e n t s , contains a large amount of c o l l o i d a l humus, i s brown, and a c i d i c . Por these reasons, the plankton populat ion and the algae of dystrophic lakes are l i m i t e d i n number. The lakes r a p i d l y turn into swamps and soon thereafter become peat bogs. This theory can very we l l be appl ied to the Camosun peat bog. At approximately 130 centimetres, Nymphaeaceae completely disappears from the p r o f i l e and the amount of p o l l e n grains of Ericaceae and the Juncus-32 Carex grcmp increases . The she l l s of diatoms are completely l ack ing from about t h i s same l e v e l , which i s also an i n d i -cat ion of the change of the l a k e . N a t u r a l l y , the trees Pinus and Tsuga d id not inhabi t the bog u n t i l l a t e r when the swampy condit ions became less wet and more appropriate for these trees . There i s , however, a very impressive i n -crease i n the p o l l e n grains of these trees l a t e r , which suggests t h e i r presence on the bog. Unfortunately t h i s supposit ion cannot be proved; i t can only be suggested on the basis of present condi t ions . At the present time, Tsuga and Ericaceae occur i n other than the peat environ-ment, but a large number of them grow also on the peat bog. Therefore i t i s poss ib le that the increase of Tsuga and Ericaceae p o l l e n was due to t h e i r invasion of the peat bog. On the other hand, Pinus contorta present ly grows only on peat i n t h i s area . It i s quite l i k e l y , therefore , that the increase of Pinus po l l en percentage occurred when t h i s tree species had begun to occupy the peat bog. In b r i e f , the plant m i c r o f o s s i l s and other combined factors ind icate that the peat bog developed from a lake through a na tura l succession. Succession of the surrounding fores t : The succession of the fores t i n t h i s region, according to the r e s u l t s of t h i s i n v e s t i g a t i o n , began with an abundance of Pinus. It appears that the forest around the lake was composed of Pinus with some Picea and 33 Abies intermixed. While Pinus contorta i s the only species of Pinus growing on the bog today, i t i s quite poss ible that the f o s s i l , found i n the ear ly hor izons , represents some other species as i t i s extremely d i f f i c u l t to d i f f e r -ent iate the various species . Of course, as the resi t l ts i n d i c a t e , there were quite a few i n d i v i d u a l s of Alnus grow-ing , probably mostly on the shores of the l a k e . Because of i t s p o s i t i o n , Alnus probably did not have to be very numerous to give a high percentage of po l l en gra ins . The d r i e r , more exposed s i t e s probably bore some Quercus species . A l t e r n a t i v e l y , Quercus p o l l e n could have come from Van-couver Is land, which was probably d r i e r and warmer, and hence more su i tab le for Quercus. At any rate the forest was e n t i r e l y d i f f e r e n t from the present fores t s of t h i s area . The vegetat ion under the forest trees was poss ib ly r i c h e r than i s ind icated by the p o l l e n record . However, the p o l l e n production of understory plants was unable to compete with the r e l a t i v e l y high production of coniferous trees , since the former are i n s e c t - p o l l i n a t e d , i n most cases, and hence would stand l e s s chance of being represented as w e l l . The other fac tor r e s t r i c t i n g these plants from representat ion i n the bog was probably the lack of wind under the forest t rees . Without wind there would be no major transport ing agent for the po l l en g r a i n s . These condit ions were r a d i c a l l y changed by some kind of catastrophe. For 20 centimetres (480 to 34 460 centimetres) a l l the coniferous tree p o l l e n grains are missing from the p o l l e n p r o f i l e , with only Alnus and Quercus representing the tree species . A poss ib le ex-p lanat ion for t h i s phenomenon i s that a huge f i r e des-troyed the former forest and the sources of po l l en grains ceased to e x i s t . It i s known that Alnus regenerates very soon a f t er a f i r e , e spec ia l l y around lakes . This tree i s able to produce flowers and hence p o l l e n grains wi th in ten years or l e s s . Hence i t i s understandable that most of the po l l en grains would be those of Alnus soon a f t e r the f i r e . The continuous occurrence of Quercus p o l l e n a f t e r the f i r e can also be explained i f i t i s assumed that oak trees were growing i n areas separated from coniferous trees i n i s o l a t e d groups before the f i r e . A l so , the f i r e res is tance of Quercus i s much greater than that of most c o n i f e r s . I f the po l l en of Quercus came from Vancouver Island then the explanation i s obvious: the f i r e would not expand that f a r and the source of po l l en grains would remain. This l a t t e r case could only be true i f there were no coni fers present on Vancouver I s land . I f there were c o n i f e r s , t h e i r po l l en would have come over here along with Quercus. A f t e r the f i r e a natura l regeneration would replace the burnt coniferous f o r e s t . Following the r e -generation there would s t i l l be a long time u n t i l the new coniferous trees could s tar t to produce p o l l e n g r a i n s . In t h i s i n t e r v a l , Alnus would be producing r e l a t i v e l y 35 l a r g e numbers o f g r a i n s , which would account f o r the h i g h f r e q u e n c i e s o f Alnus p o l l e n f o l l o w i n g the f i r e . The r e c o r d shows the composition of the f o r -est changed a f t e r the catastrophe and the p r e v i o u s l y domi-nant t r e e s , e.g. Pinus and P i c e a were r e p l a c e d by new s p e c i e s , e.g. Pseudotsuga and Tsuga. This replacement of the p r e v i o u s l y dominant s p e c i e s probably i n d i c a t e s changes i n the environment, mostly c l i m a t i c changes. This p o s s i b i l i t y i s d i s c u s s e d more thoroughly i n c o n n e c t i o n w i t h the c l i m a t i c changes (page 38). Por the present there i s only one t h i n g to add: the environment probably d i d not change suddenly. I t more l i k e l y changed g r a d u a l l y . However, the v e g e t a t i o n would not r e f l e c t t h i s g r a d u a l change because the s t i l l - e x i s t i n g Pinus f o r e s t s would suppress the r e g e n e r a t i o n o f Pseudotsuga. T h i s l a t t e r s p e c i e s " . . . r e q u i r e s freedom from shade i n order to regen-erate s u c c e s s f u l l y . . . . 1 1 ( F o r e s t r y Handbook f o r B r i t i s h Columbia, page 558). The necessary freedom from shade would have been r e a l i z e d f o l l o w i n g the f i r e . I t appears t h a t f o l l o w i n g the f i r e (480 to 470 c e n t i m e t r e s ) , Tsuga was probably not a climax t r e e , as i t o c c u r r e d i n small numbers r e l a t i v e to Pseudotsuga. Pinus and P i c e a a l s o regenerated l a t e r (460 c e n t i m e t r e s ) , but i n much s m a l l e r numbers than b e f o r e , i n d i c a t i n g t h a t the climax s p e c i e s had changed; the o r i -g i n a l a s s o c i a t i o n w i t h Pinus dominant became an a s s o c i a t i o n , w i t h Pseudotsuga dominant. 36 The environmental condit ions were probably good for t h i s new composition of fores t f o r quite a long time, f o r the chart shows only minor changes u n t i l quite r e c e n t l y . These minor changes i n the percentages could have been caused by various f a c t o r s , such as: f i r e s which destroyed the forest i n part or i n whole; maturation and regeneration of some of the tree species; and the invas ion of some of the herbaceous species into the v i c i n i t y of the sample, at times i n overwhelming q u a n t i t i e s . What-ever the causes, the r e l a t i v e percentage of the p o l l e n grains of the forest trees changed only recent ly , at ap-proximately the l e v e l of 30 centimetres. At t h i s l e v e l , Pseudotsuga decreases to a very low percentage of ap-proximately 5fo. Even the present vegetat ional s tructure indicates a very low percentage, of Pseudotsuga, and much higher number of Alnus , Thuja and Tsuga. Unfortunately, the p o l l e n grains of Thuja do not preserve i n most cases. Other inves t igators have also found the lack of Thuja p o l l e n very c h a r a c t e r i s t i c i n peat deposits (Hansen, 1940). This problem w i l l be d i s c u s s e d l a t e r i n connection with future work suggestions. The explanation of .the decrease of Pseudo- tsuga can be given as man's se l ec t ive encroachment. Pseudotsuga was probably growing r e l a t i v e l y w e l l , as some of the large o ld trees i n d i c a t e . Man, i n need of nearby timber, cut the l a r g e r ones, l eav ing the l e s s valuable and smaller trees i n p lace . 37 Another poss ib le explanation i s l i n k e d to a na tura l cause. According to t h i s explanation, the climate has been trending towards cooler and more moist condi t ions . This would probably cause a change from the present Coastal Douglas f i r a s soc ia t ion to the Coastal V/estern hemlock a s s o c i a t i o n . This i s , of course, only t h e o r e t i c a l at the present and more proof would be necessary to draw f i n a l conclus ions . The increase of Tsuga could have been caused purely by l o c a l invas ion of t h i s species into the peat bog, rather than by a major change i n the fores t a s soc ia t ions . The r e l a t i v e l y high frequency of Picea could be explained by the fac t that i t s po l l en i s quite buoyant, and hence i t can t r a v e l far ther distances than some other species . I t i s also poss ible that Picea po l l en produc-t i v i t y i s quite h i g h . At present, Picea appears very sparsely i n the Point Grey area, and probably was not important at any time i n the succession of the vegetat ion. The other tree species are not very common i n the core, and occurred only i n smaller frequencies . The problem of the forest succession can be summarized as fo l lows: the ear ly deposits had a p o l l e n content i n d i c a t i n g an abundance of Pinus. This changed into another a s soc ia t ion i n which Pseudotsuga was the dominant species . The p o s s i b i l i t y i s that i n present times, t h i s a s soc ia t ion i s changing again into a new one i n which Tsuga w i l l be a co-dominant species with Thuja. 38 t Climatic changes: The suggestions of c l imat i c changes are also based on the r e s u l t s because the whole subject i s b u i l t upon the vegetat ional changes. E c o l o g i c a l studies suggest that one of the most important environmental fac tors i s the climate-. I f the climate changes the vegetat ion usual ly r e f l e c t s t h i s change, provided the change i s on a more or less permanent basis so that the succession has time to take p lace . Of course, the same climate does not alv/ays develop the same vegetation because of the effect of other f a c t o r s . Nevertheless, one can draw reasonable conclusions concerning the climate from the vegetat ion. As the r e s u l t s ind icate the f i r s t fores t was composed of Pinus with some Picea and Abies . Quercus probably grew on the more exposed, d r i e r and warmer s i t e s . The ericaceous plants were probably completely lack ing at th i s time. The vegetation as a whole indicates a warmer, d r i e r period than at present. But i t i s poss ible that th i s climate was already changing into a more moist, cooler.one soon a f t e r the f i r s t m i c r o f o s s i l deposi ts . This suggestion i s supported by the fac t that the forest developing a f t er the f i r e was composed of new species which found the d i f f erent condit ions more sui table for themselves than they were for the previous t rees . This changed climate was probably cooler and wetter than the preceding one, for the new species were 39 Pseudotsuga and Tsuga. Both, of these genera require r e l a t i v e l y higher amounts of p r e c i p i t a t i o n and can stand cooler condit ions than Pinus and P icea . Alnus was also very common as the r e s u l t s show; th i s species also r e -quires moist s o i l . Another s ign of the cooler climate a f t er the f i r e i s the disappearance of the p o l l e n grains of Quercus from the p r o f i l e . These trees probably were not destroyed at the same time by the f i r e but were destroyed l a t e r , pos s ib ly e i ther by another f i r e or by natura l death. Because of unfavourable condit ions they could not regen-erate . One of these unfavourable condit ions was the cooler c l imate, and the other was the fact that the condit ions were more suited to new species which hindered the regen-erat ion of Quercus. The cl imate d id not change much fo l lowing the advent of the cooler and wetter period a f t e r the f i r e , except that i t probably was becoming progress ive ly cooler and more moist as time passed. At present i t seems to be even wetter and cooler than fo l lowing the f i r e and the appearance of Pseudotsuga and Tsuga. This hypothesis i s based on the fact that pseudotsuga seems to be l o s i n g i t s importance to Tsuga and probably also to Thuja. Unfor-tunately , the po l l en grains of the l a t t e r cannot be found i n peat; th i s suggestion, therefore , can only be supported by the present assoc ia t ion of the two species . Nowadays Thuja i s abundant i n the close v i c i n i t y of the peat bog. 40 Pseudotsuga appears to be giving way to Tsuga and Thuja. This may be either natural occurrence or caused solely by man's encroachment. In the former case, the statement may stand that the climate has grad-u a l l y been grov/ing cooler and wetter since at least the f i r s t appearance of Pseudotsuga and Tsuga. In summary, there was probably only one major change i n climate since the f i r s t pollen deposits, v i z . from a warmer and d r i e r climate indicated by Pinus to a cooler and more moist climate characterized by Pseudotsuga and Tsuga. This change was i n progress at the time of the deposits of the f i r s t specimens or shortly thereafter. There i s also a suggestion that t h i s climate i s at the present becoming s t i l l cooler and wetter. This i s suggested by the decrease of Pseudo- tsuga and increase of Tsuga and probably also Thuja. Age determination: The age determination of the bottom layers of the sample creates a problem. The easiest and most dependable determination would be the carbon-dating method but t h i s i s a very costly process. Therefore a comparative method had to be used to achieve a reason-able conclusion regarding the age of the f i r s t deposits. The comparison was made with Hansen's (1947) r e s u l t s . According to h i s conclusions there were three climatic periods i n the P a c i f i c Northwest i n p o s t - g l a c i a l 41 time. The f i r s t per iod , which showed a tendency towards increas ing warmth and dryness began i n l a t e - g l a c i a l time, about f i f t e e n thousand years ago, reaching i t s maximum approximately eight thousand years ago. The second per iod , more pert inent to th i s study, was a stage o i maximum warmth and dryness f o r about four thousand years (eight to four thousand years ago). The next per iod , from four thousand years to the present, shows a tendency to a cooler and more moist c l imate . As was shown previous ly (page 38) the f i r s t of the samples ind icates a warm and dry c l imate . But i t was also shown that t h i s climate s tar ted , probably soon, to change into one that was cooler and wetter. This f ind ing l i m i t s the time of the f i r s t m i c r o f o s s i l deposits to w i th in eight to four thousand years ago. But Hansen also found a we l l defined l a y e r of vo lcanic ash i n most of h i s samples from the West Coast which was deposited approximately s ix thousand years ago. This l ayer v/as searched for but lias not been found i n the sample taken by the w r i t e r , i n sp i te of the fact that h i s a t tent ion was c a l l e d to i t s poss ible occur-rence. Therefore i t can be stated safe ly that the v o l -canic ash layer was missing from the core . This fact suggests that the f i r s t i d e n t i f i e d micro fos s i l s were deposited less than s ix thousand years ago. The lower dep ths contained s i l t y c lay i n which an ash l a y e r could not be t raced . 42 T h i s c o n c l u s i o n s e t s the age o f the bottom l a y e r s o f the core sample between s i x and f o u r thou-sand y e a r s . T h i s seems to be the c l o s e s t l i m i t a t i o n one can g i v e without u s i n g the r e s u l t s o f the carbon-dating method. I f the v e g e t a t i o n was the same i n the v i c i n i t y o f t h i s peat bog as i n the v i c i n i t i e s of the bogs s t u d i e d by Hansen (1940) i n New Westminster and L u l u I s l a n d the comparison would probably have been e a s i e r , f o r these bogs were ve r y c l o s e to the p r e s e n t l y d i s c u s s e d Camosun bog. However, there are so many f a c -t o r s i n f l u e n c i n g the development of the v e g e t a t i o n t h a t l a r g e changes can occur even i n such s h o r t d i s t a n c e s . On the o t h e r hand the d i v i s i o n s of h i s samples were on a much l a r g e r s c a l e (25-centimetre d i v i s i o n s ) . Another f a c t o r i s t h a t the depths of the bogs were not the same (Hew Westminster: 425 c e n t i m e t r e s ; L u l u I s l a n d : 500 cen-t i m e t r e s ; Camosun: 570 c e n t i m e t r e s ) . For these d i f f e r -ences, any comparison c o u l d o n l y be based on the deduced c l i m a t i c i n t e r p r e t a t i o n s , which were not g i v e n by Hansen i n h i s s t u d i e s . The present i n t e r p r e t a t i o n , t h e r e f o r e , had to be based on the more g e n e r a l i z e d r e s u l t s f o r the P a c i f i c Northwest (Hansen, 1947). The age of the f i r s t d e p o s i t s then i s prob-a b l y younger than s i x thousand but o l d e r than f o u r thou-sand y e a r s f o r the sample a r e a . 43 Suggestions for future inves t iga t ions : The present i n v e s t i g a t i o n of the Camosun peat bog can be considered only as a pre l iminary study "because only one sample was taken. Therefore, as was mentioned prev ious ly , these r e s u l t s cannot be appl ied to the whole bog. The ice cover of the l a s t g l a c i a t i o n r e -treated from th i s area approximately 10,500 years ago (Dr. W.H. Mathews, personal communication, 1961). The studied sample represents a maximum age of s ix thousand years . Therefore i t i s poss ible .that the vegetation may have s tarted e a r l i e r than the present sample i n d i c a t e s . I t could have been that the depos i t ion layers reached th i s l e v e l of the lake at approximately s ix to four thou-sand years ago. Some parts of the bog may be deeper and may contain micro fos s i l s of greater ages. For t h i s reason the f i r s t step i n further study should be to take a ser ies of test samples at various s i t e s i n the bog. The longest of the cores obtained should then be div ided and macerated, as was done with the core of t h i s present study, and the r e s u l t s of the two cores should be compared. The other samples would serve as reference samples and at c e r t a i n depths a specimen of each should be macerated to check with the o r i g i n a l r e s u l t s . I f the r e s u l t s were corroborated by these l a t e r cores, they could then be genera l ized . By taking several samples from the peat bog 44 at various places an opportunity would "be given to the inves t igator to map the bog more accurate ly h o r i z o n -t a l l y at each l e v e l . Also knowledge could be obtained of the v e r t i c a l sect ion of the peat bog based on these new core samples. The next important step would be a more accurate age determination, which should be done at l eas t for the bottom layer (the deepest l a y e r ) . It would also be very useful to determine the age of those succeeding layers which ind icate c l i m a t i c changes. For th i s age determination the carbon-dating method would be most r e l i a b l e . Knowing these ages one could safely state the approximate age of the peat bog and also could give very accurate dates of the vegetat ional changes which would be r e f l e c t i n g c l imat i c changes. Of course, i t would only be r e l i a b l e i f most of the samples gave sim-i l a r r e s u l t s . The above-described suggestions concern the Camosun peat bog s p e c i f i c a l l y . However, a s i m i l a r procedure could be appl icable to any peat depos i t . At the present, some of the r e s u l t s of pa lyno log ica l studies must be i n t e r p r e t i v e , for we do not have enough information on various factors i n f l u -encing po l l en and spore a n a l y s i s , such as: the po l l en product iv i ty of d i f f eren t p lants; migration distances of these gra ins ; and the degree of preservat ion of 45 di f f erent species i n various media. These fac tors would great ly influence the p r o f i l e . Tor example, i f there are a few i n d i v i d u a l s of h igh-pol len-producing species growing among low-producing species which are more numerous, the di f ference probably w i l l not be shown i n the r e l a t i v e percentages. The high p o l l e n produc-t i v i t y would compensate for the number. To el iminate these d i s t o r t i o n s there should be some inves t igat ions of the r e l a t i v e pol len-produc-t i v i t y of d i f f erent species, the migration distance of various gra ins , and preservat ion studies i n d i f f erent media of the grains of various species . Some pre l im-inary studies already have been done on each subject but no systematic r e s u l t s have been given to date. • Natura l ly , the frequency of a given species i n a sample would be l i m i t e d by the c o l l e c t i v e inf luence of the above-mentioned factors upon i t s g r a i n s . How-ever, i f these factors were studied f i r s t i n d i v i d u a l l y , and secondly c o l l e c t i v e l y , conclusions could be more exactly drawn concerning the d i s t r i b u t i o n and frequency of p lants , and eco log ica l condi t ions . Branches of trees could be i so la t ed before p o l l i n a t i o n to study the po l l en p r o d u c t i v i t y . But these r e s u l t s could only be used i f the r e l a t i v e distances of po l l en migration were also s tudied . For t h i s study, s tat ions would have to be used for c o l l e c t i n g po l l en grains from the a i r , with notes as to the d i f f e r e n t wind 46 d i r e c t i o n s . When th i s study i s done another has to fol low; namely, the d e f i n i t i o n of the percentage of the d i f f erent species i n the assoc iat ions from where the co l l ec ted grains came. Knowing these facts conclusions could be drawn concerning the r e l a t i v e po l l en content from wel l described assoc iat ions at d i f f erent d is tances . These data could be used i n pa lyno log ica l studies to give more standardized r e s u l t s . Furthermore, there i s one 'other fac tor which should be ca l cu la ted , v i z . the preservat ion percentage. The preservat ion percentage would supply the pa lynolo-g i s t s with the percent i l e preservat ion of the po l l en of d i f f erent plant species i n various media. Any r e s u l t s w i l l obviously be affected by th i s f a c t o r . More s p e c i f i c a l l y , there should be a cor-r e c t i o n fac tor appl ied to each species i n d i f f eren t media which would be derived through the study of the three above described fac tors ; namely, r e l a t i v e produc-t i v i t y , migration distance, and degree of preservat ion . For some species the l a t t e r would be p r a c t i c a l l y zero and therefore the whole fac tor would be p r a c t i c a l l y zero. In some cases, however, several grains might be preserved, which could disproport ionate representat ion . This would apply, f or instance, to Thuja,. The so lut ion for t h i s problem would be to determine which species have zero preservat ion r a t i n g s , and to disregard them i n pa lyno log ica l s tudies , even i f they should happen to 47 occur i n some samples. These suggested inves t iga t ions would need time, hard work, and f i n a n c i a l support. The r e s u l t s , however, would he worth the work and money spent on the studies for they would enable future palynologis t s to produce f a r better and more r e l i a b l e conclusions . Summary of conclusions: The author's conclusions, based on the r e -su l t s of the po l l en analys i s of the Camosun peat bog, can be summarized b r i e f l y as fo l lows: 1. The peat bog appears to have developed from a p o s t - g l a c i a l lake as a natura l success ion. , This theory i s supported by the po l l en p r o f i l e con-ta in ing t y p i c a l lake and peat bog vegetation and also by the presence and disappearance of diatoms. 2. The vegetation of the surroundings was sylvan. The fores ts have d e f i n i t e l y changed at l eas t once from Pinus fores ts into Pseudotsuga forests and probably they are now changing into fores ts character ized by Tsuga and quite l i k e l y Thuja. 3. The climate has changed at l east once, as indicated by vegetat ional changes of the surrounding fore s t s . This change was a change from a warmer and d r i e r climate to a cooler and more moist c l imate . There i s speculat ion that th i s climate i s turning even cooler and more moist i n present times, but t h i s cannot 48 be proved c o n c l u s i v e l y by the r e s u l t s . 4. The approximate age determination, based on a comparison of the present r e s u l t s w i t h those of Hansen (1947), i n d i c a t e s an approximate 3,ge of between s i x to four thousand years. This age i s w i t h reference to the f i r s t m i c r o f o s s i l deposits obtained from -the core sample. 49 LITERATURE CITED Armstrong, J.E. 1956. S u r f i c i a l geology of Vancouver area, B r i t i s h Columbia. G e o l o g i c a l Survey of Canada, paper 55-40. Hansen, H.P. 1940. Palaeoecology of two peat bogs i n southwestern B r i t i s h Columbia. American Journal of Botany, March, 1940. Hansen, H.P. 1947. P o s t g l a c i a l f o r e s t succession, c l i m a t e , and chronology i n the P a c i f i c North-west. Transaction of the American P h i l o -s o p h i c a l Society, Vol.37, Par t 1. Heusser, C.J. I960. L a t e - P l e i s t o c e n e environments of n o r t h P a c i f i c North America. American Geographical S o c i e t y , Broadway at 156th S t r e e t , New York, N.Y. Johnston, W.A. 1923. Geology of Fraser River D e l t a Map-area. No. 116 G e o l o g i c a l S e r i e s , Geo-l o g i c a l Survey. Soo, R. 1953. Novenyfoldrajz. Tankonyvkiado, Buda-pest. Terasmae, J . 1958. C o n t r i b u t i o n to Canadian palynology. G e o l o g i c a l Survey of Canada, B u l l e t i n 46, Ottawa. Terasmae, J . and F y l e s , J.G. 1959. P a l a e o b o t a n i c a l study of l a t e - g l a c i a l deposits from Vancouver I s l a n d , B r i t i s h Columbia. Canadian Journal of Botany, 50 vol. 37. Terasmae, J. and Hughes, 0. L. I960. Glacial retreat in the North Bay area, Ontario. Science, vol. 131, No. 3411. 1959. Forestry handbook for British Columbia. The Forest Club of U.B.C., Vancouver. 51 PLATE I Arboreal p o l l e n grains A l l f igures ca . x500 1 Alnus sp. (Tourn.) L . 2 Pseudotsuga menz ie s i i . (Mirb. ) Franco 3 Tsuga he terophy l la . Sarg. 4 Pinus sp. L . 5 Abies sp. (Tourn.) L . 6 Picea sp. L i n k . 7 L a r i x sp. Tourn. ex Adana. ^ Quercus garryana. Dougl. 9 Betula sp. (Tourn.) L. 10 Sa l ix sp. (Tourn.) L . 11 Acer sp. (Tourn.) L. LATE I I 1 3 to 8 g o 1 I l I ! I ?OM 53 PLATE II Non arboreal po l l en grains A l l f igures ca . x500. 1 Oarex-Juncus group. 14 A c h i l l e a sp. L . 2 Carex-Juncus group. 15 Caryophyllaceae. 3 Er icaceae . 16 Chenopodium sp. (Tourn;) L . 4 Pteridium sp. Scop. 17 Drosera sp. L . 5 Sphagnum sp. 18 Dryopteris sp. Adans. 6 Gramineae. 19 Desmidiospora 7 Nymphaeaceae. 20 Helianthus sp. L . 8 Nymphaeaceae. 21 I lex sp. (Tourn.) L . 9 Lycopodium sp. L . 22 Myrica sp. L . 10 .Typha sp. L . 23 Polypodium sp. L . 11 Typha l a t i f o l i a . L . 24 Plantago sp. L . 12 Artemis ia sp. L . 25 Saxifraga sp. L . 13 Leguminosae. 26 Spiraea sp. L . -27 Leguminosae. 54 CHART I POLLEN PROFILE OF CAMOSUN PEAT BOG. Also occur red in t races and were counted but not <V N.B. 5T i i i i O 30 o zo o zo o\o o A R B O R E A L N 0 N - A R w o zooio 0 10 B 0 R E A recorded on graphs ARBOREAL ACER SALIX NON-ARBOREAL ACHILLEA C A R Y O P H Y L L A C E A E CHENOPODIUM DROSERA DRYOPTERIS SP. FUNGAL SP HEL IANTHUS ? I LEX? MOSS SP MYRICA MYRIOPHYLLUM PLANTAGO POLYPODIUM S A X I F R A G A S P I R A E A TRIFOLIUM ? L i 

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