Reboisement in France: or, Records of the replanting of the Alps, the Cevennes, and the Pyrenees with trees, herbage, and bush, with a view to arresting and preventing the destructive consequences and effects of torrents

Front matter

3 9424 04545 450 8

1.1 «

5t I'

Section I. — The Phenomena of Alpine Torrents, . . .15

Gives the distinguishing characteristics of rivers, of torrential rivers, of torrents, and of mountain streams; of different classes of torrents, of glacier torrents, and of torrents hlanc (p. 15) ; detailed information is given in regard to the beds of torrents, and the continuation of these in the ravines of the mountains, and in regard to the tliahcerj or inclination of the valleys, and to the operation of flowing water in the formation of these (p. 17) ; in regard to Bassins de reception, or basins drained by torrents (p, 21); to Canaux d'econlement, or water-courses ; to Lits de deiection, or beds of deposit (p. 23) ; and in regard to torrential fleods of water ; to the occasion of these, and to the avalanche-like effects produced by them (p, 25).

Section II. — Natural History of Alpine Torrents, . . .30

It is stated that there may be seen in the Alps old beds of torrential deposit covered with vegetation of many years growth, which proves that ihe torrtuts forming them have long ceased to flow ; and that such may be seen in various stages of advancement, indicating different periods of extinction of torrents of a former day (p. 30) ; that in view of these and other facts observed, the history of a torrent may be considered as marked by thrte periods— that of tho creation of the curve of the bed, that of the deepening and enlarging of this, but with the course inconstant, and that with this stable and fixed,— followed in the cases referred to by the extinction of the torrent (p. 33) ; tiiat many torrents have originated from mountain.?, or mountain sides, having be* n denuded by the clearing away of forests ; and that they have owed their development to the combined operation of deluges of rain (p. 34), the nature of the soil, and the consequent contour of the country(p. 36)— the latter an effect as really as a cause of the flood (p. 38).

Section III. — Remedial Applia^ices to prevent the destrnctive consequences of Torrents, . . . . . .41

What were sought to be prevented were inundations, the washing away of lands, and the ruin of fertile fields by the deposit on them of the detritus washed away (p, 41). Embankments were employed to prevent inundations, but without success (p. 44.) Tho other evils were not less serious, of which illus-

^ CONTENTS.

tratioui are given, and the remcJits at first employed were retaining walls, palisades, wears of vaiied structure, and coffers, but the evi's still prevailed (p. 45). It having been observed by M. Surell that the origin of many torrents might be traced to the destruction of forests, and that the extinction of torrents was attributable to the extension of forests (p. 46), he laid down as established facts — (1), that the existence of a forest on a soil prevents the formation of a torrent there, and (2), that the destruction of forests leaves the soil subject to become the prey of a torrent; and hp recommended (p. 51), as appropriate remedies for the evils experienced, extensive properly directed plantation of trees, the exclusion of cattle from pronerly selected spots to allow of the growth on these of herbage and bush, and in subordination to the carrying out of these measures such artificial structures of defence as might be called for, — which measures are detailed.

PART II. — Literature relative to Alpine Torrents, and Remedial Measures proposed for adoption to prevent

THE disastrous CONSEQUENCES FOLLOWING FROM THEM,

Contains notices of treatises and proposals by Fabre, 1759 (p. 55) ; Lecreulx, 1804 (p. 59): Hericart de Thury. 1806 (p. .59); Ladoucette, 1834 (p, 60); Dugied (p. 60), Surell (p. 65), Delafont (p, 66), Jousse de Fontaniere (p. 66), Labecke (p. 67), Chevalier (p. 69), Bhuiqui (p. 70), Bonville (p. 72), Belgrand (p. 73), Valles (p. 7i), Delbergue-Cormont (p. 75), Rozet (p. 78), Scipion Gras (p. 79), Breton (p. 82), Culmann (p. 84), Revue des Deux Mondes (p. 91), Marschand. who treats of the hydroscopicity, capillarity, permeability, and impermeability of soil (p. 94), Cezanne, in a supplement to Etude des Torrents by Surell, with notices of phenomena referred by him to what he calls a torrential era following the glacial period in pre-Adamite times (p. 101) ; Costa de Bastelica, who treats of what he designates Torrentiality, or torrential phenomena, in contradistinction to the fiow of limpid water, and alleges that by this may phenomena referred by Cezanne to glacial action be accounted for (p. Ill) ; explains the phenomena of stones bounding in advance of a torrent wave (p. 117); discusses the extinction of torrents by toisemett^ (p. 118) ; by gazonnement (p. 121) ; and by Jarra</es (p, 123) ; treats of Oolmataqe or Avarpage in connection with these, and applies his views of t(jrrentiality to account for geological phenomena (p. 127). And thars is given a list of other works on the subject in French (p 129), in Greraian (p. 132), and in Italian (p. 133), and quotations from works in English by Marsh (p. 134), Arthur Young (p. 136), and Duile (H6).

PART III. — Legislative ii.ND Executive Measures taken by the Government of France, in connection with Reboisement

AS A REMEDIAL application AGAINST DESTRUCTIVE ToRRENTS, . 137

In the 14th century edicts were issued anil other means were employed to arrest the destruction of forests, as a means of arresting the destruction which was being wrought by torrents. These are referred to, and there are given translations of the text, and of copious extracts from the Act-Decree of the Mk Tliermidor an XIII. relative to the torrents of the department of the High Alp^ (p. 138) ; Act of 16th September, 1800, and law of 16th September, 1807, relative to tlie execution of works required to prevent destructive effects of sucb torrents (p 140).

The state of matters about the time of the publication of Mr Surell's work, and for some years thereafter, till the destructive inumlations in 1856 leH to the isstie of a letter from the late Emperor Napoleon, de.sirint; attention to be given to the cause or occasion of .such inundations, with a view to the employment of appropriate remedies (p. 117); and flifire are given translations in Avhole of (1) the Report {;iven in reply to the Emperor by the Miiiister of Finance, published ;:{rd February I860 (p. U7); (2) Law founded thereon, promulgated on 28rh July 1860 (o. li)2) ; f3) r^rcular in relation thereto, addressed to Conservators of forests by the Director General of the Forest Administration on 17th August 18G0 (p. 154); (4) Decree embodying the Statute of the Public Administration for the enforcement of the said laws issued 27th April 1861 ; (.5) Circular addressed to Conservators of forest by the Director General of the Forest Admin-sfration commTmicatinjr explanations of said decree, issued Ist June 1861 (p. 103).

Translations in whole or in part are given of [D Kesu nd of First Annual C<mfercnce of Agents employed, instituttul by Ministerial decision of 21st November 1861, and held on the 9th, lO'h, and Uth December, at Valance for the reifion of the Alps, at Aurillac for the region of mountains in central France, and at Tarbes for the region of the Pyrenees (p. 171) ; (2) Report for 1861

CONTENTS. V

(p. 1801 ; (3) Eesame of the Second of Mie Annual Conferences of forest agents specially charged \vii;h the replanting of mountains with woods in the different districts of France, instituted by Ministerial decision of 21st Nov. 1831. held on 8th Sept^-mber 1862, and days following, at Clermont Ferrand for the region of the mountains of central France ; at the same date, at Carpentras for thft region of the Alps; and on 15th Sep. and davs following, at Foix for the region of the Pyrenees (p. 181) ; (4) Report for 1862 (p. 200) ; (5) Report for 1863 (p. 203) ; (6) Report for 1864 (p. 206) ; (7) Report for 1865-6t3 ; (8) Rpport for 1867-68.

To meet difficulties arising out of popular opposition to the operations, a mixed commission was appointed to carry out in combination this law and a land-improvement act which had been passed at the same time, under the title Loi du 28 jui'let 1860, relative d la mise^ en valevr des Marais et des Terres incul^es appartenant aux Communes; but this measure having failed to meet the case (p. 208), additional legislation was required; and there are given translation** of (1) Expose des Motifs, or reasons assigned for the legislation (p. 209) ; (2) The Supplementary Law of 8th June 1864, completing in regard to gazonnement the law of 28th Jul v. in regard to the rehoisement o{t\\Q mountains (p. 215) ; and (3) The Decree embodying the regulations of the Public Administration of the two laws of the 28th July 1860 and the 8th June 1861. in regard to the rehoisement and gazonnement of the mountains (p, 210). In 1865 this law came into operation, and th^re is reported what was done in the years 1865 and 1866 (p. 223), Some delay had occurred in the opening of this report, and the Administration was enabled to embo-ly in this a report of the success of the operation, as tested by extensive inundations which occurred in the autumn of 1866 (p. 224) ; and a report on the difference between the expense of the works of rehoisement and works oi gazontiement, and the cause or occasion of this difference (p. 239), In August 1866 there was issued bv the Director-General of the Administration of Forests a circular containing instructions and directions in regard to all matters pertaining to the work (p. 231). And with the report of operations in the years 1867 and 1838 was given a tabulated statement of the areas upon which operations had been carried out in the several years which had elapsed from the publication of the law of 28th July 1860, with a statement of the expenditure involved (p. 231)

PART IV. — Past, Present, and Prospective Aspects of the

Chap. I. — Fast History of Aljnne Torrents, . . . 234

Information supplementary to what had been given in connection with the con- .^ideration of the literature of this subject is supplied in regard to the views of Marsh (p. 235). of Marschand (p. 236), and Gras (p. 237) in regard to the past history of torrents in France.

Chap. II. — Existing Forests, ..... 238

There is cited the testimony of Becquerel in regard to the extent of existing forests in France, and of Marschand in regard to the position of forests in the mountain ranges (p. 238).

Chap. III. — Laivs Regulating the Rehoisement Effected and Measures

There is cited an abortive law submitted to the Chamber of Deputies in the Session of 1847, and in connection with a reference to the cause of its failure to effect anything is stated wherein the law of 1860 differed from it (p. 240) j and there are enumerated and described the kinds of works by which the object of this law had been accomplished during the first decade of the operations carried on (p. 241).

Chap. IV. — Devastations occasioned by Torrents ivhich it was sought to Arrest and Prevent, and Measures employed, . . . 242

Details are given to show, as was subsequently seen by ihe population of the mountains, that in the operations carried on they had a bmeficiary interest as real as that of inhabitants of the valleys and of th'i plains, for which they considered that their interests wee being sacrificed (p. 242) ; a brief but detailed description of the measures employed is given (p. 249); and of the kinds of trees and bushes made use of in different situations (p. 254), and different localities (p. 256)-

Chap. V. — Devastations and Restorations, .... 257 In this chapter are given detailed information in regard to the work being carried on in different localities within the first decade, showing what was undertaken and what had been effected in different departments of France, embracing the following J—

VI CONTENTS.

Sect. I.— The High Alps, ...... 257

There is given the description of the state of devastation which moved Surell to act (p. 258), cited by the Director-General of the Forest Administration, with details of what had been effected in remedying the evil, given by M. Gentil in a report to Conseil General des Hautes Alpes in 1869 (p. 259), and a corresponding report given in 1868 by a commission appointed by that body (p, 260); and this is followed by details of what had been the state of the valley of the Durance (p, 261), and of what had been done (p. 264), and with what results (p. 265).

Sect. II. — Department of the Isere, . . . .267

There is given an account of Dauphiny and Provence hy Marsh, based on a work by Charles de Ribbe (p. 267), and detailed information of what had been done in the p^rim^^re of the Bourg-d'Oisans (p. 268).

Sect. III. — DejKirtment of the Drome, .... 271

This department was formerly included in the Independent State of Dauphiny. There is detailed what had been done in the p^rimfetre of Luc in the arrondissement of Die (p 271).

Sect. l\\—The Loiver AIjjs, . . . . _ . 272

Details are given of what had been done in the p^rimHre of Labouret in the arrondissement of Digne (p. 272), and notices of what had been effected by .Tourdan, a simple forest warder (p. 274).

Sect. V. — Department of the Ardeche in Central France, . . 275

Information in regard to this district is supplied in the words of M. Marsh, founded on statements by M. Mardigny (p. 275), and corresponding information supplied by M. Ce'zanne (p 278).

Sect. VI. — Department of the Gard, . . . . 279

Details are given of works undertaken and executed in the perimfetre of Ponteils (p. 279).

Sect. VII. — Department of Lozere, ..... 280 The sad condition of the district, and the benefits of hoisement are described as described by the prefect of Lozbre (p. 280).

Sect. VIII. — Department of the Loire and of Haute Loire, . .283

The practicability of improving the ba3in of the Loire by hoisement, as described by M. Cezanne (p. 283).

Sect. IX. — Department of Heraidt, .... 284

Details are given of works executed in the p(^rimfetre of Riols (p 284).

Sect. X. — The Pyrenees, . . . • • .285

The French Pyrenees are described by Weld (p. 285-291), and there is reported the rehoiHement in p^rimetre of Bareges (p. 297).

Sect. XI. — Department of VAiide, ..... 307 Details are given of operations in the p(^rimbtre of I'Argente Double (p. 307).

Chap. VI. — Local Feeling and PiLblic Opinion in regard to Rehoise

There is given information in regard to proceedings in different sessions of the Conseil G^n^ral of the High Alps (p. 312), to change of tone after 1865 (p. 313), to testimony of M. Sequinard, Conservator of Forests in the district (p. 314), to testimony of commissioners appointed by the Conseil G^ndral (p. 316), to proceedings in the Conseil Genc^raux of other departments (p. 317), to testimony of M. Far^, Director General of the Administration of Forests (p. 318), and of the National Assembly (p. 319).

Chap. VII. — Present Position and Prosjoects of the Enterprise, . 320

There are cited anticipations by M. Surell (p. 321), description of the present by M. Cezanne (p. 323). and details by M. Gentil of what has been effected (p. 324).

There is given an account of the inundation of Toulouse (p 329), and of Ilankey (p. 337), and Port Elizabeth in South Africa, as illustrative of a phase of torrents, common to many lands, which reheisement may meet, and the first mentioned, the inundation of Toulouse, is studied in the light of what has been effected (p. 339).

INDEX OF AUTHORITIES CITED

IN ADDITION TO OFFICIAL DOCUMENTS EMBODIED IN THE COMPILATION.

Antoine d'Abadie, page 11.

Battivilla, 183. Becquerel, 238. Belancier, 129. Belgrand, 73, 129, 131. Berlepsch, 133. Blanqui, 70. Bonville, 72. Breton, 82, 103. Broignard, 74.

Daily News, 331. Darcy et Bazin, 129. Delafont, 66. Belbergue-Cormant, 75. Dugied, 35, 60. Duile, 132, 136. Dumont, 129, 145. Dupuit, 130.

Eastern Province Herald, 339. Escher, 89.

Gentil, 324. Gauloes, 332. Graeff, 130. Gras, 79, 237, 243. Guide Joanne, 87.

Hagen, 131. Hall, 334. Hericart de Thury, 59, 97. Heyer, 132.

Jamieson, 106. Journal des Debats, 333, 346, 348. Jousse de Fontaniere, 10, 66

Kloden, 132. Krantz, 130.

Rapport au Conseil Provincial de Luxemburg, 130. Rappen, 133. Reclus, 248. Ribbe, 74, 266. Rosa, 133. Rozet, 74, 78.

Valles, 74. Van den Brinken, 133. Venez, 87. Vigan, 130. Vicaire, 154, 163, 171, 180. Von Arrentin, 131. Von Berg, 132. Von Zaltinger, 131.

Zanotti, 133.

Preface

In a treatise on the Hydrology of South Africa 1 have given details of destructive effects of torrential floods at the Cape of Good Hope and Natal, and referred to the measures adopted in France to prevent the occurrence of similar disastrous floods there. The attention of the Legislative Assembly at the Cape of Good Hope was, last year, called by one of the members of the Assembly to the importance of planting trees on unproductive Crown lands. On learning that this had been done I addressed to the editor of the Cape Argus a communication, of which the following is a copy : —

My last communicatiou shows, I coasider, no lack of interest on my part iu whatever may tend to secure the coasei'vation and impi-oved maaagemedt of the forests of the Colony ; but important as I consider the fact that attention is being given by the Legislature to a suggestion by the Conservator of forests at the Zitzikamma, having this for its object, 1 attach still more importance to the faet that attention is being called in the Legislative Assembly to the question of the expediency of planting Crown lands with trees.

In several other countries the same work has been begun ; and the evils against one or more of which they are seeking in these countries to protect themselves by planting trees by the million, are all of them already to be met with at the Cape, and many of them are to be met with there at the same time and in the same place, all mustering in full force, while elsewhere iu many cases it is only the anticipation and dread of some one or other of them, or the partial prevalence of them, which has prompted to the precautionary measure. At the Cape, throughout extensive districts, we meet with want of fuel, multitudes being driven to the use of mist in cooking food, and multitudes more numerous being unable to obtain even this ; winds powerful, if not terrific, sweep over the land, with hail and tempest ; droughts, long-continued droughts, alternate with deluges of rain and thunderstorms ; heat by day in some districts is succeeded not uufrequeutly by frosty nights; locusts and coel;/cin(jtr,s remind one of wliat is written of Judea, " That which the palmerworm hath left hath the locust eaten, and that which the locusk hath left hath the cankerworra eaten, and that which the cankerworm hath left hath the caterpillar eaten ;'' and then, when it is least expected — the sky unclouded, the sun or the moon shining in its brightness, — down comes a river, carrying all before its wave.

A li Preface.

These are evils, the dread of oue or other, or of some combination of which, is prompting many elsewhere to labour like men chained to the pumps of a vessel foundering at sea, in the hope that they may yet avert what they fear ; and the measures adopted by them are similar to those to which reference has been made. My ears still ring with the echoes of Rehoisement, and the corresponding terms applied to the operation of planting or replanting forests where they have been destroyed ; and I cannot but hope that the means thus employed, if adequate to avert the dreaded evil, might prove to some extent an appropriate remedy for the evil where it exists. I say nothing at present of what may have brought about the present state of things. I admit the importance of the consideration of this in discussing in full the subject ; but it is enough for me, and it will probably be deemed enough by many of your readers, that I am satisfied 1 am giving safe advice in saying, — Look to what men are doing elsewhere !

Wishing to give unity and completeness to my communication, I shall at present refer only to what is being done to bridle torrents by planting trees, knowing that the torrents of the Colony have been destructive both of life and property to a very great extent, and that almost every year has its doleful renewal of such calamities.

Torrents have proved destructive on the continent of Europe by washing away

i' fertile soil, by undermining houses and fields, and whole villages and towns, and

.. causing their fall, by burying fields and vineyards and towns in the debris thus

■ produced, and swept away, and by producing extensive inundations of lower lying

' ■ level lands, drowning man and beast, and burying, washing away, or otherwise

destroying the labour of years. Your readers will know to what extent the

parallel holds, and to what extent it fails, in the destructive effects of torrents at

the Cape, or in the districts in which they reside. Having thus indicated the evil,

I would briefly advert to the remedial measures which have been adopted.

One of the means employed to avert destruction when it was threatened, was e the erection on the river-bed of protecting walls, and of advanced structures, to determine the current, and of continuous slopes to regulate its rapidity and force, and of combined and modified forms of all of these appliances, which manifested L great art and skill, ingenuity, and power. It would be exaggeration to say they proved in every case an utter failure, but this would only be an exaggeration of what was the fact, which was, that in very many cases they failed to avert the evil, and in not a few cases they were carried away before the torrent like chaff before the wind, while the torrent seemed to laugh a loud and hollow laugh at the silliness of man's device.

To prevent the destruction of land by inundations, the more promising measure of raising embankments based or founded on the dry land was adopted, and the river was thus chained within its bed, with only liberty of action within a limited space beyond. But what did the river do ? It silted up its bed, and thus raised itself, and attempted to overflow the embankment. The danger was perceived in time, and the embankments were raised to a higher elevation. The river quietly repeated the silting up of its bed, which was met by a repeated addition to the embankment. This was done again and again. It was a continuoas struggle between dead matter and living mind, carried on for years — for generations,— both refusing to give in. Meanwhile, as in the case of the River Fo, not only the embankments, but the silted-up bed of the river was elevated considerably above the level of the country lying on one side and on the other, an aqueduct of earth overtopping and threatening with destruction houses and trees, and man and beast alike. Then it was a desperate and a deadly struggle, which many saw it would have been well it had never been entered on, while others looked on and said. It is evident that that is not the way in which the evil is to be averted. Meanwhile the struggle was continued, until a breach was at length effected in the embankment, and the river poured forth its torrent, inundating the country far and wide.

While this contest was going on, the study of torrents in the Alps revealed the form of the bed of these to be a largo somewhat semi-circular funnel-shaped basin, from the rainfall in which the waters were cuUcctcd, — u channel more or

PKEFACE. iii

less elongated, along whicli the waters flowed, — and a fan-shaped bed of deposit corresponding to the delta of a river, the whole being like to a river-bed reduced or contracted in length ; it showed, further, that theise torrents were to be met with in all stages of progress, from incipient formation, throughout various stages of activity, to linal extiDction ; it showed that in forest- covered mountain regions there were none; that in denuded mountain ranges they were numerous, and sometimes very destructive; that, where they were extinct, the forest had extended itself till it covered the basin and lined the banks of the channel ; that where they were in a state of progressive extinction, the forests were progressively extending themselves ; and that this extension of the forest was apparently the cause or occasion of the extinction of the torrent.

From what had thus been observed the inference was drawn that by artificial plantation the gradual extinction or the subjection of the torrent to control might be effected,— and numerous facts which had been long known were recalled to give their testimony in confirmation of the correctness of the inference drawn. Kain falling on a metallic roof rushes off, while the same rain falling on a thatched roof trickles down in drops ; from the bared ground the rain runs off in streamlets long before it runs off in a similar way from the grass-field or the thicket ; and the more the phenomena of percolation and drainage was studied the more manifest did it become that vegetation retarded the flow and prevented the rush of water, retained it to moisten the soil, and extinguished the torrent requiring the river to take days and weeks to carry away what the torrent carried away in hours, and thus securing something like a permanent flow in what had become a dry channel, filled occasionally from bank to bank with a destructive torrent, converting the lion into a lamb. And now millions of francs are being spent on the work of planting trees, and herbage, and bush, with a view to preventing torrents and inundations destroying the laud.

It does not comport with my purpose to discuss details. I wish simply to open up the previous question, — Is it expedient to give consideration to this? It may be objected, — It would be a gigantic work by which anything could be done to bridle the torrents of the Cape ! It would ; no one knows that better than I do : and I think it probable that no one has any such conception of the magnitude of the enterprize as I have ; but it is by gigantic struggles that the capabilities of a people are developed. It may be objected, — It would require a gigantic expenditure I It would ; but what is the cost of the destruction of property, to say nothing of the destruction of life, which these torrents at present occasion ? I have before me details of destructive effects of torrents which have occurred since I left the Colony in the beginning of 1<S67. Towards the close of that year there occurred one, the damage occasioned by which to roads and to house property at Port Elizabeth alone was estimated at from £25,000 to £30,000. Within a year thereafter a similar destructive torrent occurred at Natal, in regard to which it was stated that the damage done to public works alone was estimated at £50,000, while the loss to private persons was estimated variously from £50,000 to £100,000. In the following year, 1809, a torrent in the Western Province occasioned the fall of a railway bridge, which issued in loss of life and loss of property, and personal injuries, for one case alone of which the railway proprietors were prosecuted for damages amounting to £5000. In Beaufort West a deluge of rain washed down the dam, and the next year the town was flooded by the waters of the Gamka ; and the next year, 1871, Victoria West was visited with a similar disaster. Such are the sums and the damages with which we have to deal in connection with this question, as it affects the case ; and these are only the most remarkable torrents of the several years referred to. I have spoken of millions of francs being spent on liehuisement in France, and some may be ready to cry out, '' jNothiug like such an expenditure can be undertaken at the Cape!" Perhaps not ; but the losses occasioned by the torrents seem to amount at present to about a million of francs m the year. This falls in a great measure on individuals, that would fall on the community ; and the community in return would benefit by water retained to fertilize tlie earth, instead of being lost in the sea, and by firewood and timber being giuwu where now there is none. Thc'ic iv PREFACE.

are facts well -deserving of consideration in the discussion of the expediency of planting Crown lands with trees.

Towards the close of last year, 1874, still more disastrous effects were produced by torrential floods. According to the report given by one of the Colonial newspapers, the damages done could not be estimated at much less than £300,000. According to the report given by another, the damage done to public works alone was estimated at £350,000, — eight millions, seven hundred and fifty thousand francs. And my attention was called anew to the subject.

On addressing myself to M. Fare, Director General of the Administration of Forests in France, there was afforded to me every facility I could desire for extending and verifying the information I had previously collected in regard to the works of reboisement to which I have referred. Copies of additional documents were supplied to me, with copies of works sanctioned by the Administration, and arrangements were made for my visiting and inspecting, with every assistance required, the works begun and the works completed ; and thus I have been enabled to submit a much more complete report than it would otherwise have been in my power to produce.