Archive for September, 2013

Trajnost lesa

Pri uporabi določene vrste lesa, je potrebno vedeti tudi njegovo trajnost v določenih okoliščinah. Trajnost lesa je namreč v vlažnih razmerah drugačna kot v suhih. V suhih nekatere vrste lesa zdržijo 1000 let in tudi več, dočim te iste v vlažnih in mokrih samo nekaj let.

  • v zemlji:
  • zelo trajen les: macesen, hrast
  • trajen les: akacija, domači kostanj, bor, brest

  • malo trajen les: smreka, jelka, breza

  • netrajen les: bukev, topol, jelša, jabor, divji kostanj, beljava vseh vrst lesov

  • v vodi:
  • zelo trajen les (prek 500 let): brest, macesen, hrast, jelša

  • trajen (do 500 let): akacija, domači kostanj, bor, gaber, smreka, jelka

  • malo trajen (50 do 100 let): topol, javor, divji kostanj

  • netrajen (do 50 let): bukev, vrba

  • na zraku:

  • zelo trajen: hrast, zelenika, macesen, bor, domači kostanj, brest, tisa

  • trajen: smreka, jelka, jesen

  • malo trajen: bukev, gaber, javor, divji kostanj, češnja, breza, lipa, topol, vrba (Tavčar, 1967)

Delovanje lesa

Razžagan in posušen les ne raste več, vendar to ne pomeni, da se njegove dimenzije in oblika ne preminjajo več. Les se suši toliko časa, dokler se njegova vlaga ne izenači z vlago v zraku. Tako kot se spreminja vlaga v zraku, se spreminja tudi vlažnost lesa in z njo tudi dimenzije lesa. Najbolj les deluje v tangencialni smeri, torej v smeri branik (do 10%), v radialni smeri od sredine debla proti obodu med 2 in 8%, najmanj pa vzdolž debla, samo okoli 0,1%.

Posamezne drevesne vrste delujejo nekako takole:

  • močno deluje: lipa, gaber, češnja, bukev, črni gaber
  • srednje močno deluje: oreh, domači in divji kostanj, javor, hrast, sadno drevje, jelša, breza, črni bor
  • malo deluje: topol, jelka, smreka, brest, macesen, bor
  • prav malo deluje: ebenovina, mahagonovina, kokosova palma (Tavčar, 1967)

Baltic states

After the fall of Soviet Union, we number among North Europe also three former Soviet republics.  Those are three Baltic states: Lithuania, Latvia and Estonia. When you travel through all three countries, passing one by one, you almost don’t see the difference in the relief. If there wouldn’t be abandoned border controls, you wouldn’t know you are in different country. Countryside almost flat, changing fields, grassland and forest. From Lithuania to Estonia countries are smaller with less inhabitants, less populated, more dense forests and higher hills. But the change is not so dramatic to notice it, unless you read about in the book before you left home and pay attention to while driving over.

Until the 18. century they had different history, when they all become part of the Tsarist Russia. After the October Revolution Lithuania, Latvia and Estonia declared independence, war for independence continued until 1920, when all three countries were recognised as independent states also by Soviet Union. Countries were independent until 1940. After the agreement between Soviet Union and Germany, three Baltic states were occupied by Soviet Union and during the Second World War by Germans. After the war Soviets returned. During the after-war Soviet occupation of Baltic states, happened here lot of inhuman events. Repression, even harder than before the war: deportations to Siberia and other towns all around Soviet union, national oppression, many were killed in after-second-world-war partisan war, many people immigrated to the West,… The situation became better after democratisation of the Soviet Union in 1980s, after Gorbachev took over the leadership of the Soviet Union. Liberation movement was live again. In 1990 Lithuania, Latvia and Estonia declared independence again. Their independence has been recognised next year also by Russia.

Vilnius

Vilnius

Hill Of the Crosses

Hill Of the Crosses

Riga

Riga

Pärnu

Pärnu

Tallinn

Tallinn

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