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areasstudiedarecoveredwithsprucemonoculture.Thebedrockisformedby
flyschsedimentsmostlyoftheCretaceousage;thesesedimentscontainaconsider-
ableproportionofclayfraction,whichlargelypreventstherainfallfrominfiltrat-
ingintothebedrock.Therefore,thesurfacerunoffcreatesadensenetworkofrills
andgullies.Inmanycases,thedeepererosivelandformsreachthegroundwater
levelandarethusrunthroughbywaterformostoftheyear,whichmayimplytheir
fastheadwardextension.
TheareasoftheMoravskoslezskeBeskydyMts.,whicharethescopeofthe
study,arelocatedintheRadhostskahornatina(theUpperOstraviceriverandits
tributaries)andLysohorskahornatinaranges(theMoravkaandLomnawatersheds,
partoftheCernaRiverwatershed).Thereliefbuiltbyrelativelyrigidflysch
sandstonesexceeds1000ma.s.l.inaltitude(LysahoraMt.1323ma.s.l.,SmrkMt.
1276ma.s.l.etc.),incontrasttotheareasmostlyformedbyclaystones,wherethe
peaksrarelyreach1000ma.s.l.Theintensityofwatererosioninwoodedareas
influencesthedensityoftheerosivenetwork,whichthenindicatesthecharacter
ofnaturalandsometimesalsoanthropogenicconditions(esp.downhill-oriented
unpavedforestroadsre-modelledintogullies).
ThedecisivesourcesofforestsoildevastationintheBeskydyMts.aregullies
andrillsnearthestreamsandthepoorconditionofunpavedforestroads,which
caneasilybetransformedintogulliesespeciallywhensituatedstraightdownhill.
InthewatershedsoftheBilaandCernaOstravicestreams,theoveralldensity
oferosivenetworkexceeds2.5km·km-2(Phot.1),sometimeseven3km·km-2;
inthewatershedsoftheMoravkaandLomnariversthedensityreachesabout
112km·km-2.
Methodologyandabriefoverview
ofthefundamentalerodologystudiescarriedout
inthemountainouswoodedareasintheNEpart
oftheCzechRepublic
Themethodforsamplingwaterwithsuspendedloadcontent,usedbytheauthor
inthestudy,waspublishedbyO.Stehl.k(1969).Onelitreofwateristakeninto
themeasuringcylinder.After24hours,approximately0.8lofwaterisdrainedand
theremaining0.2latthebottomofthecylinder,wherethesuspendedloadhas
settled,isthendriedat120°C.Inthisway,veryfineparticlesrangingfromclayto
sandareretained(colloidparticleswouldnotbedetectedbecausetheirsedimenta-
tiontakeslongtime).Theweightofthesedimentwasmeasuredwithaccuracyof
0.1mgper1litreofwater.Thesampleswithsuspendedloadcontentweretaken
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