Männiku uuendamine turberaiega Järvselja näidis-katsealal
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Kuupäev
2014
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Ajakirja pealkiri
Ajakirja ISSN
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Abstrakt
Enamus Eesti metsadest uuendatakse lageraiega, turberaiete osakaal uuendusraietest oli
metsateatiste väljastamise alusel 2011. aastal 9%. Seoses majandamispiirangutega metsade
suure osakaalu ja metsanduskaugete inimeste negatiivse suhtumisega lageraiesse on hea
lahendus suurendada turberaie osa. Turberaiete kasutamisel on mitmeid väheuuritud probleeme:
noorte puude valgus- ja juurkonkurents vana metsa puudega; loodusliku uuenduse vähene
elujõud ja ebapiisav arvukus; võrreldes lageraiega kallim puidu ülestöötamine jms.
Turberaietega seotud probleemide uurimiseks rajati 2012. aastal Järvselja ÕKMK-s männiku
uuendamise näidis-katseala.
Magistritöö eesmärgiks on leida turberaiete läbiviimiseks senisest efektiivsemaid võtteid, mis
aitaks kaasa nende suuremale rakendamisele kaitstavates metsades, maanteede ääres ning ka
erametsanduses. Töös võrreldakse kolme turberaieviisi (aegjärkne-, veer- ja häilraie) ja nelja
uuendusviisi (paljasjuursed istutatud taimed; istutatud potitaimed; külvatud seemned ja
looduslikult tekkiv uuendus). Uuritakse ka maapinna mineraliseerimise, vana metsa puude ning
uuenduse väetamise mõju. Esitatakse ülevaade teistest Järvselja turberaiete näidis-katsealaga
seotud uuringutest.
Magistritöö käigus mõõdeti 2014. aasta kevadel Järvselja turberaiete näidis-katsealal taimede
kõrgus ja eelmise aasta juurdekasv. 2013. aasta kevadel väetati 507 proovilappi (istutatud
puude ja külvi teel tekkinud uuenduse lapid) NPK väetisega ning võeti sama aasta sügisel 74
mulla- ja okkaproovi väetamise mõju selgitamiseks.
Töö tulemustest selgus, et pärast teist kasvuaastat oli istutatud taimede kõrgus suurim veerraie
paljasjuursetel taimedel ning väikseim aegjärkse raie alal kasvavatel taimedel. Istutatud taimede
viimase aasta ladvavõrse pikkus oli suurim veerraiel ning väikseim aegjärksel raiel. Kuigi
väetatud taimed olid keskmiselt kõrgemad, siis väetamise mõju esimese väetamisjärgse aasta
kõrguskasvule ei ole usaldatav. Taimede säilivus sõltus väetamisest ning raieviisist. Väetatud
taimed olid iga raieviisi korral parema säilivusega, mõju oli nõrgem aegjärkse raie korral,
parimad tulemused olid häilraiel. Taimede kõrgus külvatud lappidel oli parim häilraiel,
loodusliku külvi puhul veerraiel, halvimad tulemused olid aegjärksel raiel. Loodusliku uuenduse
arvukus oli suurema seemnepuude arvu tõttu parem aegjärksel raiel. Taimede arvukus teisel
kasvuaastal oli inimese poolt külvatud lappidel vähenenud, aga suurenenud loodusliku külvi
lappidel. Mulla ja männiokaste toiteelementide sisalduses avaldusid väetamisjärgsed muutused
eelkõige mulla P ja K sisalduse ning okaste P sisalduse suurenemises.
Magistritöö tulemuste põhjal võib väita, et veerraie on kõige efektiivsem turberaieviis.
Soovitada võib suuremaid, kuni 40 m diameetriga häile ja võrreldes metsamajandamise
eeskirjas kehtiva aegjärkse raie esimese etapi lubatava minimaalse täiusega madalamat täiust.
Samuti tuleks suurendada veerraie lubatavat laiust. Väetamise mõju taimede kasvule ei ole peale
esimest kasvuperioodi tõestatud, kuid mullas on PK sisaldus suurenenud ning järgmistel
kasvuaastatel võib mõju olla selgem. Magistritöö kinnitas, et maapinna mineraliseerimine on
efektiivne viis loodusliku uuenduse tekke ja säilimise tagamiseks. Järgnevates uurimustes
katsealal tuleb jätkata uuenduse kordamineku ja kasvu jälgimist, et mõista paremini erinevate
turberaieviiside ja metsauuendamisvõtete mõju.
Most of Estonian forests are cut, using clear cut felling; only small part (about 9% in 2011) is cut using shelterwood system. There exists large amount of protected forest area in Estonia and growing discontent in public opinion concerning clear cut felling. It seems that different shelterwood systems are good alternative to clear cuttings in protected areas and, for example, near motorways and also in private forestry. Due to the complexity of shelterwood system, there are many problems using it more widely in forestry. A shelterwood system study area was created in Järvselja in 2012 to investigate three different shelterwood systems in Scots pine stand using different regeneration (planting, sowing and natural regeneration). The aim of the master thesis is to find more effective solutions using shelterwood system and analyze the effects of different shelterwood systems (shelterwood uniform system, group selection and shelterwood strip felling) on different regeneration. In addition, the effect of soil scarification and using NPK fertilizer is studied and also a short overview of other researches carried out in the study area is presented. Most of the data for the master thesis were collected in spring 2014 including data about total height and height increment in last year. In spring of 2013, 507 plots were fertilized with NPK 21:11:11 fertilizer and 144 soil and needle samples were collected to estimate the difference between fertilized and unfertilized plots. The main result of the thesis is that shelterwood strip felling is the most effective method concerning regeneration height and the shelterwood uniform system produced the lowest heights. Although fertilized planted plants were higher on average, there was no statistically significant difference. The survival of planted plants is affected by fertilizer and shelterwood system. Fertilized plants were healthier than unfertilized and the highest mortality was in shelterwood uniform system, and the lowest in group selection. Sowed plants were the highest in group selection and natural regeneration in shelterwood strip felling, the worst results were in shelterwood uniform system. The number of seedlings was higher in shelterwood uniform system. The number of seedlings was reduced compared to previous year on sowed plots and the number increased on natural regeneration plots. Adding NPK fertilizer to the plots increased P and K in soil and P in needles. The main conclusion of the thesis is that shelterwood uniform system is the most effective shelterwood system concerning planting and regeneration. Also, in order to shelterwood systems be more effective there should be possibility to use wider strips, lager groups in group selection and lower stem density in sheletrwood uniform system. The effect of fertilizer could become more visible in the following years and soil scarification is very important in shelterwood systems on mineral soils to prevent the competition from ground vegetation. In conclusion, a well planned shelterwood system could be a promising alternative to clear cut fellings in protected and populated areas. In future, monitoring of the study area must continue to understand more about the effects of different shelterwood systems in Scots pine stands in Estonia.
Most of Estonian forests are cut, using clear cut felling; only small part (about 9% in 2011) is cut using shelterwood system. There exists large amount of protected forest area in Estonia and growing discontent in public opinion concerning clear cut felling. It seems that different shelterwood systems are good alternative to clear cuttings in protected areas and, for example, near motorways and also in private forestry. Due to the complexity of shelterwood system, there are many problems using it more widely in forestry. A shelterwood system study area was created in Järvselja in 2012 to investigate three different shelterwood systems in Scots pine stand using different regeneration (planting, sowing and natural regeneration). The aim of the master thesis is to find more effective solutions using shelterwood system and analyze the effects of different shelterwood systems (shelterwood uniform system, group selection and shelterwood strip felling) on different regeneration. In addition, the effect of soil scarification and using NPK fertilizer is studied and also a short overview of other researches carried out in the study area is presented. Most of the data for the master thesis were collected in spring 2014 including data about total height and height increment in last year. In spring of 2013, 507 plots were fertilized with NPK 21:11:11 fertilizer and 144 soil and needle samples were collected to estimate the difference between fertilized and unfertilized plots. The main result of the thesis is that shelterwood strip felling is the most effective method concerning regeneration height and the shelterwood uniform system produced the lowest heights. Although fertilized planted plants were higher on average, there was no statistically significant difference. The survival of planted plants is affected by fertilizer and shelterwood system. Fertilized plants were healthier than unfertilized and the highest mortality was in shelterwood uniform system, and the lowest in group selection. Sowed plants were the highest in group selection and natural regeneration in shelterwood strip felling, the worst results were in shelterwood uniform system. The number of seedlings was higher in shelterwood uniform system. The number of seedlings was reduced compared to previous year on sowed plots and the number increased on natural regeneration plots. Adding NPK fertilizer to the plots increased P and K in soil and P in needles. The main conclusion of the thesis is that shelterwood uniform system is the most effective shelterwood system concerning planting and regeneration. Also, in order to shelterwood systems be more effective there should be possibility to use wider strips, lager groups in group selection and lower stem density in sheletrwood uniform system. The effect of fertilizer could become more visible in the following years and soil scarification is very important in shelterwood systems on mineral soils to prevent the competition from ground vegetation. In conclusion, a well planned shelterwood system could be a promising alternative to clear cut fellings in protected and populated areas. In future, monitoring of the study area must continue to understand more about the effects of different shelterwood systems in Scots pine stands in Estonia.
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