Barje
Barje je mokrišče, kjer se nabira šota, kot posledica odmrlega rastlinskega materiala, pogosto mahov. Barje je eno od štirih glavnih vrst mokrišč ( ostala so močvirje, rečne mrtvice, stoječe vode ). Barja najpogosteje nastanejo tam kjer je površinska voda kisla in revna s hranili. V nekaterih primerih se mokrišča preskrbujejo samo s padavinami. Voda , ki odteka iz barja ima je značilno rjavo barvo, kot posledica tanina, ki se sprošča iz šote. Nizka rodovitnost tal in hladno podnebje silita rastline v počasno rast , razpad odmrlih delov pa je še počasnejši zaradi nasičenosti tal. Nastaja šota, ki se kopiči. Velika območja pokrajine so lahko pokrita z več metri debelo plastjo šote. Barja imajo zato zelo specifične rastlinske in živalske vrste.
Barja se lahko razvijejo v različnih pogojih, odvisno od podnebja in topografije. Eden od načinov za njihovo razvrščanje temelji na njihovem položaju v pokrajini in njihov vir vode.
Lovrenško barje
Lovrenško barje je začelo nastajati pred približno 8000-9000 leti, po koncu ledene dobe. Lovrenška jezera so posledica depresij v kamninski podlagi, pohorskem tonalitu, znani magmatski kamnini, iz katere je zgrajen osrednji del Pohorja. V preteklosti so ga imenovali pohorski granit. Podrobne raziskave so pokazale, da se sestava pohorskega tonalita nekoliko razlikuje od sestave klasičnega tonalita in da je zanj najustreznejše ime granodiorit.
Kotanje ali depresije je kmalu zapolnila voda. Območja so se spremenila v jezera ali ravna močvirnata območja, nad bodisi kislo ali ne kislo podlago. Skozi stoletja so se območja preoblikovala iz jezer, v mokrišča , močvirja poraščena z gozdom, v šotišča, barje ali z muljem in šoto zapolnjena jezera.
Sčasoma se šota kopiči na raven, kjer je zemeljsko površje tako položno , da talne in površinske vode več ne dosežejo sredine mokrišča. Ta del zato postane v celoti odvisen od padavin (ombrotrophic) in kisli pogoji omogočijo razvoj barja (tudi če je podlaga ne kisla).
Šota v barjih je pomembno mesto za skladiščenje ogljika. Če bi šota organsko razpadla, bi se v ozračje sprostil ogljikov dioksid , kar bi prispevalo h globalnemu segrevanju. Pod pravimi pogoji, je šota prvi korak pri nastajanju premoga.
Primer šote.
Močvirje še vedno tvori šoto in počasi se celotno mokrišče dviguje nad okolico: nastane barje. Višina dvignjenega območja v središču je običajno nekaj metrov nad okolico in je pogosto obdano s predeli močvirja ter prehaja v druge vrste mokrišč, kamor podtalnica še lahko prodira.
Nižinsko barje se razlikuje od visokega v tem, da je manj kislo, ima višjo stopnjo hranilnih snovi in lahko podpira bolj pestro rastlinsko in živalsko skupnost.
Anaerobno okolje (voda z malo vsebnostjo kisika), in prisotnost čreslove kisline (tanina) v barjih lahko povzroči izjemno ohranitev organskega materiala. V nekaterih barjih so se ohranila stara hrastova in druga debla, uporabna v dendrokronologiji (datiranje starosti dreves, ugotavljanje klimatskih sprememb na podlagi letnic v lesu ) in zelo dobro ohranjena trupla z nedotaknjenimi organi, kožo in lasmi, ki so padla tja tisoče let nazaj.
Lovrenška jezera, na nadmorski višini med 1529 m in najnižjim delom na na 1517 m nimajo površinskega dotoka. Napajajo ga izključno dež in druge padavine. Dejstvo, da je voda v njih vedno pristona, ne glede na položaj grebena in občasne poletne suše, pričajo o veliki zmožnosti zadrževanja vode, ki jih imajo šotišča in šota. Plast šote v osrednjem delu barja je globoka do 290 cm, na obrobju je postopoma tanjša. Celotno barje je preraščeno z ruševjem, ki na obeh straneh barja prehaja v bolj strm naklon in se spreminja v borov in smrekov gozd.
Barje sestavljata dve območji, med seboj ločeni le z ozkim pasom smrek . Dvajset jezerc ali barskih oken, ki so njegova poglavitna značilnost, je prinesla ime, Lovrenška jezera, celotni površini 22 ha velikega barja. Jezerca so naravne kotanje s površino nekaj kvadratnih metrov in globino do 1,2 m. Zaradi nadmorske višine nam pohorska barja pričarajo pokrajinske značilnosti pojezerij in resav severne Evrope. V podobnih nadmorskih višinah najdemo taka barja še marsikje v Alpah, pri nas pa so pohorska barja skupaj s pokljuškimi in jelovškimi barji najdlje na jug pomaknjena pokrajina tega tipa v Evropi, zato so nekaj posebnega.
Območje Lovrenškega barja je del največjega slovenskega gozdnega rezervata, Ribniško – Lovrenška jezera, ki obsega 522 ha. Ob najvišjem ležečem jezercu je postavljen lesen razgledni stolp.
Od Hotela na Rogli (P1) vodi dobro označena in zmerna peš pot. Dostop je možen tudi iz smeri "Koča na Pesku« (P2). Obe poti sta dobro označeni z markacijami in smerokazi "Lovrenška jezera."
Vprašanja, ki jih morate odgovoriti za vpis zemeljskega zaklada:
1. V bližini naslovnih koordinat se nahaj razgledni stolp. Koliko stopnic vodi na razgledno ploščad?
2. Ob vznožju razglednega stolpa boste našli informacijske table. Kdaj so nastala Lovrenška jezera? (Naloga spremenjena 18.8.2023, zaradi novih info tabel)
3. Opišite kaj lahko vidite na dnu malih jezerc.
4. Približno kako visoko je rastlinstvo v neposredni bližini jezer in kako se spreminja z oddaljevanjem?
-Pred vpisom zemeljskega zaklada, posljite odgovore preko GC profila. Za vpis ne potrebujete dodatnega dovoljenja. Na pošto z odgovori bomo odgovorili takoj, ko bo mogoče.
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ENGLISH
Bog
A bog is a wetland that accumulates peat, a deposit of dead plant material—often mosses. It is one of the four main types of wetlands. Other names for bogs include mire, quagmire and muskeg. Bogs occur where the water at the ground surface is acidic and low in nutrients. In some cases, the water is entirely rain-fed. Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general the low fertility and cool climate results in relatively slow plant growth, but decay is even slower owing to the saturated soil. Hence peat accumulates. Large areas of landscape can be covered many meters deep in peat. Bogs have a distinctive group of plant and animal species.
Bog habitats may develop in various situations, depending on the climate and topography. One way of classifying them is based upon their location in the landscape, and their source of water.
Bog of Lovrenc lakes
Bogs of Lovrenc lakes started to develop about 8000-9000 years ago, after the end of the Ice Age. Lovrenc lakes formed due to depressions in the bedrock, the Pohorje tonalite, known igneous rocks from which the central part of Pohorje is built. In the past the rock was called Pohorje granite. Detailed studies have shown that the composition of Pohorje tonalite differs from classical composition to tonalite and its most appropriate name is granodiorite.
The depressions left behind, were covered by water. They formed a lake or flat marshy area, over either non-acidic or acidic substrates.Over centuries there is a progression from open lake, to marsh, then fen (or on acidic substrates, valley bog) and carr, as silt or peat fill the lake.
Fens are peat-forming ground wetlands. Fens differ from bogs in that they are less accidic, have higher nutrient levels and can support a more diverse plant and animal community.
Eventually peat builds up to a level where the land surface is too flat for ground or surface water to reach the centre of the wetland. This part therefore becomes wholly rain-fed (ombrotrophic), and the resulting acidic conditions allow the development of bog (even if the substrate is non-acidic).
The peat in bogs is an important place for the storage of carbon. If the peat decayed, carbon dioxide would be released to the atmosphere, contributing to global warming. This ecological service is generally known as carbon storage or climate regulation. Under the right conditions, peat is the earliest stage in the formation of coal.
Example of peat.
The bog continues to form peat, and over time a shallow dome of bog peat can develop. The dome varies between 13 m at the whole area of Lovrenc bogs and is surrounded by strips of fen or other wetland vegetation at the edges or along streamsides, where ground water can percolate into the wetland.
The anaerobic environment and presence of tannic acids within bogs can result in the remarkable preservation of organic material. Some bogs have preserved ancient oaklogs useful in dendrochronology (tree-ring dating) and they have yielded extremely well preserved bog bodies, with organs, skin, and hair intact, buried there thousands of years ago.
Lovrenc lakes - high peat swampland , at an altitude between 1529 m and the lowest part at a 1517 m has no surface water inflow. Powered solely by rainwater. The fact that the water in them, despite the position of the ridge and occasional summer drought, witnesses to the great ability to retain water, which have peat moss and peat. A layer of peat in the central part of the moor is up to 290 cm thick, in the outskirts is getting thinner. The whole march area is overgrown by dwarf pines, which passes on either side of the marsh on steeper slopes and turning into a pine and spruce forest.
Twenty peat-lakes, the windows of the moor that were formed here has an an area of several square meters and a depth of 1.2 m. These small peat lakes also brought the name Lovrenc lakes to the whole 22 ha big area of this raised bog. Due to its altitude, Pohorje bogs have similar landscape features such as lake and heathland of northern Europe. In similar altitudes such bogs are found in many places in the Alps, together with the Pokljuka bogs and marshes Jelovec, the Lovrenc bogs are shifted furthest to the south region of this type in Europe, so they feel special.
Lovrenc marsh area is a part of the largest Slovenian Forest Reserve Ribnica - Lovrenc lakes of an area of 522 ha. At the highest altitude lake is a wooden lookout tower.
From the hotel Rogla (P1) leads a well marked and easy path. Access is also possible from "Koca na Pesku" (P2). Both routes are well marked with markings and signposts "Lovrenska jezera".
Questions you should answer prior to log the find:
1. Near head coordinates you will find a lookout tower. How many stairs are leading to the viewing platform?
2. At the ground level of the lookout tower you will find some info boards. How old are Pohorje moors? (Qustion changed 18.8.2023, because of the new iinfo-boards)
3. Describe what can be seen at the bottom of the small lakes?
4. Approximately how high is the vegetation in near vicinity of the lakes and how does it change in the distance?
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