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| ŠUMARSKI LIST 13/2005 str. 41 <-- 41 --> PDF |
P. Kantor: POSSIBILITIES OF MOUNTAIN FORESTS IN REDUCING HIGH WATERS AND FLOODS Šumarski list SUPLEMENT (2005), 31-39 2. From the aspect of ecological stability and safety of yield and production, one of evident priorities of forestry is the transformation of spruce monocultures to mixed stands. However, research results have proved, that the increased proportion of broadleaves cannot decrease the danger of high waters and floods. Broadleaved species are able to retain and draw less precipitation water than coniferous species (particularly spruce) with respect to their leafless state out of the growing season and smaller biomass of assimilatory organs. 3. Upland and mountain forests (unlike all non-forest ecosystems) reduce very easily rainstorms up to 50 mm. Uninterrupted precipitation up to 100 mm manifests itself in the total amount of runoff from the forest but from the aspect of water-management effectiveness is still acceptable. A threshold of 150 to 200 mm of uninterrupted precipitation can be considered to be a critical limit for the effective reduction of floods by the forest. Under conditions of this precipitation total, forest soil is always completely saturated by water including depressions both in the soil surface and the parent rock stratum. Then, uncontrolled and spontaneous runoff occurs through the whole soil profile appearing often on the soil surface irrespective of a species composition or the method of management. In other words, also the forest soil body shows, similarly as eg reservoirs, its capacity possibilities which cannot be exceeded. |
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P. Kantor: POSSIBILITIES OF MOUNTAIN FORESTS IN REDUCING HIGH WATERS AND FLOODS Šumarski list SUPLEMKNT (2005). 31-39 Switzerland. Similar comparative studies were gradually carried out in other forestry-developed European countries. Also Czechoslovakia participated in the research. Water-management problems were studied in the forested Kychova river watershed and in the unwooded watershed of the Zdechovka river (Välek 1958, 1977). After World War 2, based on the incentive of academicians Maran and Lhota, water-management research was concentrated on the region of the Moravian-Silesian Beskids. In an uninterrupted series since 1953 (!), basic problems are studied of "forest and water" in two fully forested partial watersheds (the Mala Räztoka watershed with autochthonous mainly beech stands and the Cervik watershed with autochthonous dominant Norway spruce). A number of immensely valuable findings from the field experiment stations can be obtained from papers of Zeleny (1971, 1974), Jara bač andChlebck (1988, 1996). Similarly oriented research programmes were established in Germany, Switzerland, Russia and other countries (Brechtel, Hoyningen-Huene 1978, Benecke, van der Ploeg 1978, Mit scherlich 1971, Schmaltz 1969 etc.). A JOINT PROJECT OF THE FACULTY OF FORESTRY AND WOOD TECHNOLOGY, MLJAF IN BRNO AND OF THE VULHM RESEARCH STATION IN OPOČNO The field of problems mentioned above concerning "forest/water" relationships tries to study also one of the research programmes of the Faculty of Forestry and Wood Technology (FFWT) in Brno in cooperation with the Research Institute of Forestry and Game Management (RIFGM) - Research Station in Opočno. The project entitled "Mountain forest ecosystems and their management aimed at reducing floods" is at present financially supported by the Grant Agency of the Czech Republic (Grant No. 526/02/0851). Permanent research plots in the cadaster of Deštne in the Orlickć hory Mts. where the water regime is studied of both main species of mountain forests, viz Norway spruce and beech in a standard commercial forest are part of the project. Spruce is usually presented to the general public as a species unsuitable from water-management aspects whereas beech is to be a species with favourable water-management effects. The measurement of all parameters of water balance of the forest stands is carried out at Deštne in an uninterrupted series since 1977. At present, a 27-year series of results is available including findings on torrent floods in July 1997, July 1998 and from the last flood in the turn of the first and the second decade of August 2002. WATER REGIME OF SPRUCE AND BEECH Water regime of forest ecosystems is primarily dependent on the supply of atmospheric precipitation, on the consumption of water by the forest (so-called summary evaporation, ie: interception + transpiration + evaporation from soil) and changes in the water supply in soil. Thus, the basic equation of water balance can be expressed as follows: 0 = S-ITE±AVp..„where O = runoff S = open area precipitation ITE = total evaporation (I = interception; T = transpiration; E = evaporation from soil) AVp = changes in the soil water supply Thus, it is possible to state that so many water flows out the forest which is not consumed for its physical evaporation (interception, evaporation from soil), physiological requirements (transpiration) and replenishment of soil water supplies. Consumption of water by forest stands - total evaporation is naturally related to the biomass of forest ecosystems, particularly the amount of assimilatory organs. It is always markedly higher in coniferous spruce stands (in the stage of pole stands and large-diameter stands on average 15 to 20 t needle dry matter per ha) than in beech stands (on average 2 to 4 t foliage dry matter per ha, namely only in the course of 5 to 7 months of the growing season). First, let us look at the simplified course of the water balance of both types of stands under comparison. At each of the precipitation, part of it is intercepted in tree crowns being later evaporated. Considering the data mentioned above, crowns of spruce trees intercept substantially more precipitation than crowns of beech trees. This fact was positively corroborated in all experimental studies (Delfs 1955, Mitscherlich 1971, Schmaltz 1969, Välek 1958, Zeleny 1974 etc.). In a spruce stand in the Orlicke hory Mts., interception amounted to, in an annual average, 210 mm (16 % precipitation), in a beech stand only 85 mm (7 % precipitation). The remaining part of precipitation falls through tree crowns to soil or occurs as stcmflow. It is of interest that the stcmflow of a mature beech tree amounts to as many as 1500 1 water at a precipitation of 50 mm. In spruce, on the other hand, the stemflow is markedly lower (at the precipitation only 30 to 50 1). |
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PRESENTATION ATTHE INTERNATIONAL SYMPOSIUM Šumarski list - SUPLEMENT (2005). 31-39 POSSIBILITIES OF MOUNTAIN FORESTS IN REDUCING HIGH WATERS AND FLOODS Petr KANTOR SUMMARY: In the course of recent 8 years, the Czech Republic was affected by three disastrous floods (July 1997, July 1998 and August 2002) induced by extremely high precipitation particularly in mountain forested locations of our country. The critique of causes and consequences of the devastating flood situations in media did not avoid even forestry. Negative effects of forest management on the intensity and extent of floods have been particularly related to high reproduction cutting and unsuitable species composition of our forests. The paper presented summarizes and comments findings obtained from permanent experimental plots in the Orlicke hory Mts. On the example of an uninterrupted series since 1977, water regime is comprehensively studied of two main species of our mountain forests, viz spruce and beech. Data are also available from all three floods. Results of the study unambiguously show that spruce and beech forests effectively mitigate continuous precipitation up to 100 mm. However, in precipitation exceeding 150 mm, the soil pro file is quite saturated with water Then, uncontrolled and spontaneous runoff occurs through the whole profile irrespective of the species composition of fo rests or methods of regeneration. INTRODUCTION Forests occupy about 34 % of the area of the Czech spruce is usually presented in public media as a species Republic. More than 50 % of precipitation falls on the which is unsuitable from the viewpoint of water manaforests. It is not because forests "attract" water but simgement. On the other hand, broadleaves are presented as ply because upland and mountain locations with high species which can significantly contribute to the reducannual precipitation totals amounting to 800 - 1500 mm tion of floods due to their high consumption of water. show the highest forest percentage in our country. However, generally it refers to unsubstantiated opinions and hypotheses lacking an actual evidence. In the introduction of the paper it is necessary to mention that during the last 200 years, the species comWhat is a reality - is it possible to answer professioposition of our forests has been markedly changed. nally a question indicated in the title of the paper? While in the natural species composition, the percentage First, it is necessary to mention that it refers to an exof conifers was only 34 % (of this Norway spruce 11 %), tremely complicated sphere of problems dealt with by at present, their proportion is more than twofold, viz forest research for a period of more than 100 years. 77 % (of this Norway spruce 54 %). At the same time, A BRIEF VIEW OF THE HISTORY OF WATER-MANAGEMENT FOREST RESEARCH The first systematic measurements of some pararied out by Krutsch in the German Tharandt as early as meters of the water regime of forest stands were car-1863(Delfs 1955). However, an internationally famous paper of E n * Prof. Ing. Petr Kantor, CSc, Department of Forest Estagier (1919) is cited even at present. In the study, wablishment and Silviculture FFWT, MUAF in Brno, Zemedelska ter regime and the course of runoff are compared in an 3, 613 00 Brno, Czech Republic e-mail: kantor@mendelu.cz unwooded and in a forested small watershed in the |
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P. Kantor: ULOGA PLANINSKIH ŠUMA U REDUKCIJI VISOKIH VODA I POPLAVA Šumarski list - SUPLEMENT (2005), 31-39 J arabač, M., A. Chlebek : Vodni ücinky lesuaekologicke vztahy. Zprävy lesn. vyzkumu, 41,1996, No. 2, pp. \-4. Kantor, P.: Vodohospodärskä funkce horskych smrkovych a bukovych porost?. Lesnictvi, 30, 1984, No. 6, pp. 471-490. Ladefoged, K.: Transpiration of forest trees in closed stands. Physiol. Plantarum, 16, 1963, No. 2, pp.993-1010. Mitscherlich, G.: Wald, Wachstum und Umwelt. Bd. 2. Waldklima und Wasserhaushalt. Frankfurt a. M., J.D. Sauerländers Verlag 1971. 365 pp. Schmaltz , J.: Die Bedeutung des Waldes für den Wasserkreislauf. Forstarchiv, 40, 1969, No. 7/8, pp.132-147. Sach, F., P. Kantor, V. Cernohous: Lesne ekosystemy, ich obhospodarovanie človekom a po vodne v Orlickych horäch v lete roku 1997. Eko lögia (Bratislava), 19, 2000, No. 1, pp. 72-91. Välek, Z.: Vyzkum hydrologickeho pusobeni smrku a buku v pramennych oblastech. Vodohosp. čas., 6, 1958, No. 2, pp. 97-115. Välek, Z.: Lesni dreviny jako vodohospodärsky a protierozni činitel. Praha, Stätni zemedelske nakladatelstvi 1977.203 pp. Zeleny, V.: Vliv pestebnich a težebnich zäsahu v lese na odtok vody. /Zäverecnä zpräva/. VÜM Zbraslav 1971.75 pp. Z e 1 e n y, V.: Vliv obnovy a premen lesnich porostu na vodni režim malych horskych povodi ve stredohorske flysove oblasti. /Zäverecnä zpräva/. VÜM Zbraslav 1974. 60 pp. |
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P. Kantor: ULOGA PLANINSKIH ŠUMA U REDUKCIJI VISOKIH VODA I POPLAVA Šumarski list - SUPLEMENT (2005). 31-39 Sa stajališta smanjenja plimnih voda i poplava, maksimalni vodni kapacitet šumskih tala je od izuzetne važnosti. Tu je najviša količina vode koju tlo može prihvatiti. U našem konkrcntom slučaju u Orlicke hory (pješčano-ilovasto tlo lake teksture do ilovasto-pješčanog kambisola s 50 % primjese skeletnog tla), ta vrijednost doseže oko 270 mm na dubini tla od 70 cm. Tijekom ljetnih mjeseci, stvarna sadržina vode u tlu obiju ZAKLJUČAK Na temelju dugoročnih serija eksperimentalnih proučavanja, ne samo u Orlickć hory, već također i u Beskidima, te analizom niza stranih studija, moguće je držati sljedeće nalaze dokazanim: 1. Površinsko otjecanje i posljedična erozija tla su zanemarive u šumskim sastojinama. Ova činjenica se ne odnosi samo na prirodne šume, nego isto tako na komercijalne šume. Čak i na posječenim čistinama procesi erozije (s iznimkom stjenovitih lokaliteta) nisu rezultat same sječe drveća, već su uvijek manifestacija loše organizirane uporabe i pokretanja teških sredstava mehanizacije i ostalih čovjekovih aktivnosti. Odsutnost površinskog otjecanja u šumi (otjecanje je također ovdje eliminirano sustavom vodnih puteva što ih stvara korijenje drveća, životinje, itd. u šumskom tlu) je u usporedbi s njegovom čestom pojavom na poljoprivrednom zemljištu tako prvi i vrlo važan uvjet za redukciju poplava u krajoliku. Kao školski primjer moguće je spomenuti lokalnu poplavu 15. srpnja 2002. u slivu rijeke Hodoninke (okrug Blansko). U doslovce nešumskom dijelu katastarskih općina Crhov i Olešnice, u samo dva sata palo je 100 do 170 mm oborine, koja je odmah otekla na poljopirvrednu površinu, te u vodotokove, prouzročivši višemilijunsku štetu, i nažalost, dvije ljudske žrtve. 2. S gledišta ekološke stabilnosti i sigurnosti prinosa i proizvodnje, jedan od očiglednih prioriteta šumar- LITERATURA Ambros, Z.: Vodnä bilancia lesnych porastov Karpät. Lesnicky časopis 24, 1978, No. 3, pp. 203-221. B e n e c k e, P., R.R. van der P1 o e g: Wald und Wasser II. Quantifizierung desWasscrumsatzes am Beispiel eines Buchen- und eines Fichtenaltbcstandes im Soiling. Forstarchiv, 49, 1978, No. 2, pp. 26-32. Brechtel, H.M., J. Hoyningen-Huene: Einfluß der Verdunstung verschiedener Vegetationsdecken auf den Gebietswasscrhaushalt. Gewässerpflege - Bodennutzung - Landschaftsschutz. Vorträge und Diskussionen der KWK Fachtagung sastojina kretala se između 170 i 190 mm, a nije padala ispod 150 mm u vrijeme bez oborina. U danom je slučaju tlo sastojina planinske smreke i bukve bilo u stanju zadržati i akumulirati od 40 do 60 mm oborinskc vode, a maksimalno 100 mm. U trenutku dosizanja punog vodnog kapaciteta, tlo se može usporediti sa potpuno natopljenom spužvom, koja nije u stanju zadržati ni milimetar druge oborine. - Conclusion stva je transformacija smrekinih monokultura u mješovite šume. Međutim, rezultati istraživanja pokazali su da povećani omjeri listača ne mogu smanjiti opasnost od plimnih voda i poplava. Bjelogorične vrste su u stanju zadržati i povući manje oborinske vode nego crnogorične vrste (posebice smreka), s obzirom na njihovo bezlisno stanje izvan sezone vegetacije, te malu biomasu organa asimilacije. 3. Visinske i planinske šume (za razliku od nešumskih ekosustava) ublažuju vrlo lako kišne oluje do 50 mm. Neprekinute oborine do 100 mm manifestiraju s ukupnom količinom otjecanja iz šume, ali s obzirom na vodno gospodarenje, djelotvornost je još uvijek prihvatljiva. Prag od 150 do 200 mm neprekinute oborine može se smatrati kritičnom granicom za djelotvornu redukciju poplava šumom. Pod uvjetima ove oborinske ukupnosti, šumsko tlo je uvijek potpuno natopljeno vodom uključujući depresije, kako na površini tla, tako i u matičnom sloju. Tada nekontrolirano i spontano otjecanje nastupa kroz cijeli profil tla, često se pojavljujući na površini tla, bez obzira na sastav vrsta ili metode gospodarenja. Drugim riječima, korpus šumskog tla također pokazuje, slično kao rezervoari, svoje kapacitetne mogućnosti, koje ne mogu biti dostignute. - References Oktober 1978 in Bad Dürkhcim, 1978, pp. 172-231. De If s, J.: Die Niederschlagszurückhaltung im Walde. Mitteilungen des Arbeitskreises, Wald und Wasser, 1995, No. 2, Koblenz. 54 pp. Engler, A.: Untersuchungen über den Einfluß des Waldes auf den Stand der Gewässer. Mitt. d. Schw. Centralanst. f. d. Forstl. Versuchsw., Bd. XII,Zurüch, 1919. Jarabäc, M., A. Chlebek: The effect of forests on the hydrological budget. Mitt. Forstl. Bundesversuchsanst. Wien, No 159, 1988, pp. 239-251. |
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P. Kantor: ULOGA PLANINSKIH ŠUMA U REDUKCIJI VISOKIH VODA I POPLAVA Šumarski list - SUPLEMENT (2005). 31-39 loge. Ako je matični sloj nepropusan, infiltrirana se voPod običnim režimom oborina, vodu iz tla poteže da mijenja u podpovršinsko otjecanje. Ako je matični korijenje drveća, kako bi osiguralo svoje fiziološke sloj pukotinastog tipa, voda prolazi u podzemnu vodu i procese (tran spi raciju). Intenzitet transpiracije u listača postaje dio podzemnog otjecanja. obično je dva do pet puta viši nego u sastojinama četinjača. S obzirom na značajno više vrijednosti biomase 1 upravo ovdje postoji bitna razlika u djelotvornosti iglica smrekovih sastojina u usporedbi s biomasom lis šumskog vodnog gospodarenja u usporedbi s poljopri tinca bukove sastojine, razlike među transpiracijama vrednim tlima, čiji je kapacitet infiltracije obično znat četinjača i listača nisu obično zamijećene. To vrlo važ no niži. Ni za vrijeme kišnih oluja ljeti 1997, 1998 i ko no otkriće potvrđuju posebice njemačka proučavanja lovoza 2002, površinsko otjecanje kod smreke i bukve od prije 30 do 40 godina (Ladefoged 1963, Mits nije bilo tako odlučujuće (Šach, Kantor, Cerno cherlich 1971, Schmaltz 1969). Slično tomu, zre h o u s 2000). I opet je potrebno spomenuti da se to u le sastojine smreke i bukve u Orlicke hory konzumirale danom slučaju odnosi na obično gospodarene šumske su za ovaj oblik evaporacije istu količinu oborina, tj. sastojine. Povećana površina otjecanja (iako općenito prosječno 180 do 200 mm godišnje. nije opasna) obično je opažena tek za vrijeme proljetnog topljenja snijega u nemješovitim bukovim sastojiNa kraju, određeni se dio vlage tla isparava neponama, gdje zbijeni sloj lišća pokazuje niži kapacitet insredno s površine -u našem se slučaju to odnosi na oko filtracije nego smrekov listinac. Čak štoviše, intenzitet 80 mm godišnje u oba tipa sastojine. topljenja u bukovim sastojinama bez lišća u sunčane je Podaci o vodnom režimu smrekovih i bukovih sadane čak za 30 % viši nego u zatvorenim smrekovim stojinama na bilansnim plohama u Orlickć hory dani su sastojinama. u Tablici 1. Tablica 1. Vodna bilanca smreke i bukve u planini Orlicke hory (900 m vis.) pri godišnjoj oborini od 1296 mm Tahle 1 Water balance of spruce and beech in the Orlicke hory Mts. (900 m alt.) at an annualprecipitation of 1296 mm Negativne komponente vodne bilance Površinsko Infiltracija do Sastojina Negative components of water balance otjecanje matične podloge Stand Intercepcija Transpiracija Evaporacija I + T+E Surface Infiltration to Interception Transpiration Evaporation / + T+ E runoff parent rock Obična smreka 212 mm 195 mm 84 mm 491 mm 13 mm 792 mm Norway spruce 16.3% 15.1 % 6.5 % 37.9 % 1.0 % 61.1 % Bukva 86 mm 181 mm 79 mm 346 mm 21 mm 929 mm Beech 6.7 % 13.9% 6.1 % 26.7 % 1.6% 71.7% Tako je evidentno da su šumki ekosustavi znatni potrošnju vode u smrekovim sastojinama nego u bukovim trošači oborinske vode. Osim nalaza iz Orlicke hory, svi sastojinama (vidi tablicu 2). Značajno viša intercepcija drugi dostupni objavljeni izvori potvrđuju bitno višu posmrekovih sastojina je glavni razlog ovih razlika. Tablica 2. Vodna bilanca zrelih sastojina smreke i bukve Table 2 Water balance of mature spruce and beech stands Oborina na Smreka Spruce Bukva Beech Autor Author otvorenom mm ukupna evaporacija otjecanje ukupna evaporacija otjecanje Područje istraživanja Precipitation open mm % mm % mm % mm % Region of research area total evaporation runoff total evaporation runoff mm mm % mm % mm % mm % Brechtel, Hoyningen582 81 554 109 Huene(1978) 663 88 12 84 16 FRG Frankfurt/ Main Beneckc, van der Ploeg (1978) FRG-Soiling 1066 616 58 450 42 515 48 551 52 Ambros(1978) Slovačka, Karpati 1100 550 50 550 50 451 41 649 59 Zeleny (1971, 1974) smreka -spruce 1080 476 604 433 817 CR-Beskidi bukva beech\ 250 44 56 35 65 Kantor (1984) CR-Orlick e hory 1296 491 38 805 62 346 27 950 73 33 |
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P. Kantor: ULOGA PLANINSKIH SUMA U REDUKCIJI VISOKIH VODA I POPLAVA Šumarski list SUPLEMENT (2005). 31-39 proučavani su u šumovitom slivu rijeke Kychova, te u nepošumljenom slivu rijeke Zdechovka (V ä 1 e k 1958, 1977). Nakon II. Svjetskog rata, na temelju poticaja akademika Marana i Lhote, istraživanje vodnog gospodarenja koncentriralo se ne regiju Moravsko-silesijskih Beskida. U neprekinutim serijama od 1953 (!) temeljni problemi "šume i voda" proučavani su u dva potpuno pošumljena djelomična sliva (sliv Mala Räztoka s autohtonim uglavnom bukovim sastojinama, te sliv Červik s autohthonim dominirajućim norveškim smrekama). Niz beskonačno vrijednih nalaza iz terenskih eksperimentalnih stanica nalazi se u člancima autora Z e 1 e n y (1971, 1974),.Iarabač iChlebek (1988, 1996). Slično orijentirani programi istraživanja ustanovljeni su u Njemačkoj, Švicarskoj, Rusiji i ostalim zemljama (Brechtel, Hoyningen-Huene 1978, Benecke, van der PI oeg 1978, M it scher 1 ich 1971, Schmaltz 1969, itd.). ZAJEDNICKI PROJEKT FAKULTETA ZA ŠUMARSTVO I DRVNU TEHNOLOGIJU, MUAF U BRNU I ISTRAŽIVAČKE STANICE VULHM U OPOČNOM A joint project of the faculty of forestry and wood technology, MUAF in Brno and of the Vulhm research station in Opočno Gore navedena problematika odnosa "šuma/voda" proučava također jedan od istraživačkih programa Fakulteta za šumarstvo i drvnu tehnologiju u Brnu u suradnji s Istraživačkim institutom šumarstva i lovnog gospodarstva, Istraživačka stanica u Opočnom. Projekt pod naslovom "Planinski šumski ekosustavi i njihovo gospodarenje s ciljem smanjenja poplava" ima trenutno financijsku podršku Agencije za dotacije Republike Čehoslovačke (Dotacija No 526/02/0851). Trajne istraživačke plohe u katastru Deštne na planini Orlickć hory, gdje se proučava vodni režim obiju vrsta planinskih VODNI REŽIM SMREKE I BUKVE Vodni režim šumskih ekosustava ponajprije je ovisan o atmosferskim oborinama, šumskoj potrošnji vode (tzv. sumarna evaporacija, tj. intercepcija + transpiracija + evaporacija iz tla) te promjenama u količini vode u tlu. Na taj se način temeljna jednadžba vodne bilance može izraziti na sljedeći način: 0 = S-ITE±AVp..., gdje je: O = otjecanje S = oborine na otvorenom 1TE = ukupna evaporacija (1 = intercepcija; T = transpiracija; E = evaporacija iz tla); AVp = promjene u pritjecanju vode u tlo. Tako je moguće ustanoviti koliko je vode isteklo iz šume koja ju nije konzumirala za fizičku evpaoraciju (intercepciju, evaporaciju iz tla), fiziološke potrebe (transpiraciju) i nadomjestak vode u tlo. Voda što ju konzumiraju šumske sastojine - ukupna evaporacija odnosi se naravno na biomasu šumskih ekosustava, posebice na količinu organa za asimilaciju. To je uvijek znatno više u smrekovim sastojinama (u stadiju šibljaka i sastojinama velikog promjera, prosječno 15 do 20 t suhog igličastog materijala po hektaru), nego u bukovim sastojinama (prosječno 2 do 4 t šuma, tj. norveške smreke i bukve u standardnoj komercijalnoj šumi dio su projekta. Smreka je obično predstavljena širokoj publici kao vrsta neprikladna sa stajališta vodnog gospodarstva, dok bukva treba biti vrsta s povoljnim vodogospodarstvenim djelovanjem. Mjerenje svih parametara vodne ravnoteže šumskih sastojina izvedena su u Deštne, u neprekinutoj seriji od 1977. Trenutno, 27-godišnja serija rezultata na raspolaganju je, uključujući nalaze o poplavama bujica u srpnju 1997, srpnju 1998, te o posljednjoj poplavi na prijelazu prve i druge dekade kolovoza 2002. - Water regime of spruce and beech suhog lisnatog materijala po hektaru, tj. samo tijekom 5 do 7 mjeseci sezone rasta). Pogledajmo najprije jednostavno komparativni tijek vodne bilance obaju tipova sastojine. Od svake pojedine oborine jedan dio kojega prihvate krošnje se kasnije ispari. S obzirom na gore spomenute podatke, krune smreka prihvate bitno više oborina nego krune bukvi. Ta je činjenica potvrđena u svim eksperimentalnim studijama (Delfs 1955, Mitscherlich 1971, Schmaltz 1969, Välek 1958, Zeleny 1974, itd.). U smrekovoj sastojini na Orlickć hory prosječna je godišnja intercepcija dosegla 210 mm (16 % oborina), a u bukovoj sastojini samo 85 mm (7 % oborina). Preostali dio oborina prolazi kroz krošnje drveća na tlo, ili se pojavljuje kao slijevanje niz deblo. Zanimljivo je da slijevanje niz zrela bukova stabla doseže čak 1500 1 vode na oborine od 50 mm. Kod smreke, međutim, slijevanje je bitno niže (uz oborine od samo 30 do 50 1). Nakon pada na šumsko tlo, oborinska se voda u njega snažno infiltrira.Osim natapanja pora tla i zatim iscijedivanja, infiltrirana voda prolazi kroz sustav vodnih prolaza do matične podloge (vodovi u šumskom tlu koje stvara korijenje drveća, životinje, itd.), teče dolje i akumulira se u šupljinama i depresijama matične pod |
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IZLAGANJE NA ZNANSTVENOM SKUPU - PRESENTATION AT THE INTERNATIONAL SYMPOSIUM Šumarski list SUPLEMENT (2005). 31-39 UDK 630* 116 ULOGA PLANINSKIH SUMA U REDUKCIJI VISOKIH VODA I POPLAVA POSSIBILITIES OF MOUNTAIN FORESTS IN REDUCING HIGH WATERS AND FLOODS Petr KANTOR* SAŽETAK: Tijekom posljednjih 8 godina, Republika Češka pretrpjela je tri katasrofalne poplave (srpanj 1997. g., srpanj 1998. g. i kolovoz 2002. g.) prouzročene izrazito obilnim oborinama, posebice u planinskim šumskim dijelovima naše zemlje. Bespoštedne kritike uzroka i posljedica poražavajućih poplava u medijima nisu zaobišle niti šumarstvo. Negativni utjecaj šumskog gospodarenja na intenzitet i razmjer poplava posebice se ogleda u jakoj oplodnoj sječi i neodgovarajućem omjeru vrsta u našim šumama. U ovom se radu sažimaju i komentiraju rezultati dobiveni iz trajnih pokusnih ploha u planinama Orlicke horv. Vodni režim smreke i bukve, dviju glavnih vrsta naših planinskih šuma iscrpno se istražuje na primjeru neprekinute serije od 1977. g. Prikazuju se i rezultati za sve tri poplave. Rezultati istraživanja nedvojbeno pokazuju da smrekove i bukove šume učinkovito ublažavaju neprekidne oborine do 100 mm. Međutim, kod oborina iznad 150 mm, profil tla je potpuno zasićen vodom, što dovodi do nekontroliranog i spontanog utjecanja kroz cijeli profil, neovisno o omjeru smjese u šumama ili metodama obnove. UVOD - Introduction Šume zauzimaju oko 34 % površine Republike Če- predstavljena u javnim medijima kao vrsta neprikladna hoslovačke. Preko 50 % oborina padne na šume. Raz- s gledišta vodnog gospodarstva. S druge strane, listače log tomu nije činjenica da šume "privlače" vodu, već su predstavljene kao vrste koje značajno doprinose rejednostavno to što visinske i planinske lokacije s viso- dukciji poplava zbog njihove velike potrošnje vode. kim godišnjim oborinama od 800 do 1500 mm imaju Međutim, to se općenito odnosi na nedokazana mišljenajveći postotak šuma u našoj zemlji. nja i hipoteze kojima nedostaju stvarni dokazi. U uvodu ovom članku važno je napomenuti da se ti- Pitanje je: je li moguće stručno odgovoriti na isto jekom posljednjih 200 godina sastav vrsta naših šuma indicirano u naslovu ovog članka? Kao prvo, potrebno značajno promijenio. Dok je u prirodnom sastavu vrsta je spomenuti da se to odnosi na krajnje složenu sferu postotak četinjača bio samo 34 % (norveška smreka problema s kojima se bavi šumsko istraživanje već 11 %), sada je njihov omjer više nego dvostruk, tj. 77 % više od 100 godina, (norveška smreka 54 %). Istovremeno je smreka obično KRATAK POGLED NA POVIJEST ISTRAŽIVANJA VODNOG GOSPODARENJA U ŠUMARSTVU A brief view of the history of water-management forest research Prva sustavna mjerenja nekih parametara vodnog Međutim, međunarodno poznati članak Engl era režima šumskih sastojina proveli su Krutsch u nje- (1919) još se danas citira. U toj studiji su vodni režim i mačkom Tharandtu već davne 1863. (Delfs 1955). tok otjecanja uspoređeni u nešumskom i u šumskom malom slivu u Švicarskoj. Slične su se komparativne * Prof. ing. Petr Kantor, CSc, Fakultet šumarstva i drvne tehnolo- studije postupno provodile u ostalim šumarsko razvije jiije, Mendelcvo sveučilište poljoprivrede i šumarstva, Zemedel- i „ „i -. r, , , ~, , , skä 3, 613 00 Brno, Czech Republic n, m europskim zemljama. I Cehoslovacka je sudjeloe- mail: kantor@mendelu.cz vala u istraživnaju. Problemi vodnog gospodarstva |
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P. Kantor: POSSIBILITIES OF MOUNTAIN FORESTS IN REDUCING HIGH WATERS AND FLOODS Šumarski list SUPLEMENT (2005) -39 After the fall on the forest soil precipitation water largely infiltrates into it. In addition to the saturation of soil pores and subsequent seepage the infiltrated water gets through the system of water paths to a parent rock (ducts in the forest soil created by roots of trees, animals etc.), runs down and accumulates in the parent rock hollows and depressions. If the parent rock stratum is impermeable the infiltrated water changes into the subsurface runoff. If the parent rock stratum is of the fissure type the water permeates to groundwater participating in underground runoff. And just here, there is a substantial difference in the water-management effectiveness of forests as compared with agricultural soils the infiltration capacity of which being usually markedly lower. Also during rainstorms inducing floods in summer 1997, 1998 and in August 2002, surface runoff in spruce and beech was not decisive (Sach, Kantor, Černohous 2000). And once again, it is necessary to mention that in the given case it refers to ordinarily managed forest stands. Increased surface runoff (although generally not dangerous) is usually noticed only during spring snowmelt in unmixed beech stands where the compact layer of leaves shows lower infiltration capacity than spruce litter. Moreover, the intensity of thawing in leafless beech stands under sunny days is even 30 % higher than in closed spruce stands. Under the usual regime of precipitation, water in soil is drawn by roots of trees to ensure their physiological processes (transpiration). Intensity of transpiration in broadleaves is usually 2 to 5 times higher than in coniferous stands. With respect to markedly higher values of the biomass of spruce stand needles as against the foliage biomass in beech stands differences between transpiration of conifers and broadleaves are usually not marked. This very important finding was corroborated particularly by German studies already 30 to 40 years ago (L a d e f o g e d 1963, M i t s c h e r lieh 1971, Schmaltz 1969). Similarly, mature stands of spruce and beech in the Orlicke hory Mts. consumed for this form of evaporation virtually the same amount of precipitation, viz on average 180 to 200 mm per year. Finally, the certain part of soil moisture is evaporated right from the soil surface - in our case it referred to about 80 mm per year in both types of stands. Data on the water regime of spruce and beech stands on balance plots in the Orlicke hory Mts. are given in Table 1. Thus, it is evident that forest ecosystems are the considerable consumer of precipitation water. Not only findings from the Orlicke hory Mts. but also all available published sources have corroborated substantially higher consumption of water by spruce stands as compared with beech stands - see Table 2. Markedly higher interception in a spruce stand is unambiguously the main cause of these differences. From the viewpoint of reducing high waters and floods the maximum water capacity of forest soils is of exceptional importance. It is the highest amount of water which can be retained by soil. In our actual case in the Orlicke hory Mts. (light-textured sandy-loam up to loamy-sandy Cambisol with a 50 % admixture of soil skeleton), its value amounted to about 270 mm at the soil depth of 70 cm. In the course of summer months, the actual water content in the soil of both stands ranged between 170 and 190 mm not decreasing below 150 mm in the period without precipitation. In the given case, the forest soil of mountain spruce and beech stands was able to retain and accumulate 40 to 60 mm precipitation water, maximally 100 mm. In the moment of achieving full water capacity, the soil can be compared to a sponge fully saturated by water which is not able to retain a millimeter of other precipitation. CONCLUSION Based on the long-time series of experimental studies not only in the Orlickć hory Mts. but also in the Beskids and through the analysis of a number of foreign studies it is possible the following basic findings to be regarded as proved: 1. Surface runoff and subsequent soil erosion are quite negligible in forest stands. This fact refers not only to natural forests but also commercial forests. Even on clear-felled areas, erosion processes (with the exception of boulder localities) are not the result of mere felling the trees but they are always a manifestation of the poorly organised use and movement of heavy means of mechanization and other activities of man. The absence of surface runoff in the forest (the runoff being also eliminated there by the system of water paths created by roots of trees, animals etc. in the forest soil) as against its often occurrence on agricultural land is thus the first and very important condition for the reduction of floods in the landscape. As a textbook example, it is possible to mention a local flood of 15 July 2002 in the Hodoninka river watershed (district of Blansko). In virtually forest-free parts of the cadaster of Crhov and Olešnice, in the course of 2 hours some 100 to 170 mm precipitation fell which immediately flew out on the surface of agricultural land into watercourses causing many-million damage to property and unfortunately even the loss of two human beings. |