Raiete mõju männipuude radiaalkasvule Järvselja harvendusraie katseala andmeil
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Kuupäev
2017
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Bakalaureusetöö eesmärk on analüüsida, kuidas Järvselja harvendusraie katsealal läbi
viidud raied on mõjutanud sealsete männipuude radiaalkasvu. Töös kasutatavad
puursüdamike andmed koguti Keskkonnainvesteeringute Keskuse projekti „Puistus
toimunud häiringute tuvastamine dendrokronoloogiliste meetoditega“ raames aastal 2011.
Katseala jaguneb kolmeks: esimesel alal viidi läbi tugev harvendusraie, teisel alal
mõõdukas ning kolmas ala jäeti kontrollalaks, kus raieid läbi ei viidud.
Raiete mõju puude radiaalkasvule analüüsiti Excel ja R vahenditega graafiliselt ning
kasutati suhtelise häiringu meetodit (Relative Growth Change - GC) ning kattuvate
ajajärkude analüüsi meetodit (Superposed Epoch Analysis - SEA).
Töö tulemustes selgub, et raied on mõjutanud puude radiaalkasvu positiivselt. Arvutatud
keskmised diameetrid ning aastarõngaste laiused näitavad, et suurimad on need tugevalt
raiutud alal ja väikseimad kontrollalal. Suhtelise häiringu meetodil leidsime suhtelise
juurdekasvumuutuse protsentides. Tugevalt raiutud ala suhteline juurdekasvumuutus on
võrreldes teiste aladega suurim ning enim kõikuv, joonistuvad välja raiejärgsed
kasvuvabanemised. Mõõdukalt raiutud alal on juurdekasvumuutus ühtlasem, peale
viimast raiet suuremaid kõikumisi näha ei ole. Kõige ühtlasema kasvuga puud olid
kontrollalal. Kõigil kolmel alal täheldati suuremat kasvumuutuste protsenti varasematel
aastatel. Olenemata sellest, et kontrollalal raieid läbi ei viidud, leidus katsealade
kasvutrendide vahel sarnasusi, mis võib viidata muule mõjutajale. Kattuvate ajajärkude
analüüsiga vaadeldi kuidas raied kajastuvad juurdekasvuindeksite seerias 5 aastat enne
raiet ning 5 aastat pärast raiet. Nähtavad tulemused saadi ainult tugeva raiega ala puhul,
mis näitas positiivseid muutusi pärast raiet esimese ning teise aasta jooksul. Mõõdukalt
raiutud ala puhul märkimisväärseid muutusi juurdekasvuindeksite seerias ei täheldatud
ning kontrollalal ei olnud võtmesündmusi, mida analüüsida.
The aim of this thesis is to analyse how thinning on Järvselja experimental plot has affected Scots pine radial growth. The samples were collected in 2011, during the project of Environment Investment Centre’s “Ascertainment of stand disturbances using dendrochronological methods”. The experimental plot is divided into three separate areas: first area was heavily thinned, on second area moderate thinning was made and the third area was control area where no thinning was made. Thinning effect on radial growth was analysed graphically using Relative Growth Change (GC) and Superposed Epoch Analysis (SEA) methods with Excel and R tools. In results we see that thinning had positive impact on scots pine radial growth. Calculated mean diameter increments and ring widths were bigger on heavily thinned area and the smallest on control area. Using relative growth change we found relative increment changes in percentages. Relative increment changes were the biggest on heavily thinned area and growth releases after thinning were revealed. On moderately thinned area the growth change is slightly smoother and after the last thinning no bigger fluctuations can be seen. The most uniform growth had the control area trees. Bigger increment growth change percentages were seen in previous years and that phenomenon occurred on all three areas. Despite the fact that on control area no thinning was made, all three areas had similarities in their growth trends, which indicates on another growth limiting factor. With superposed epoch analysis we analysed how thinning reflects in increment index series 5 years before thinning and 5 years after thinning. Positive results were found only heavily thinned area. It showed us that, on first and second year after thinning increment changes were positive. On moderately thinned area no remarkable changes were found and on control area we did not have event to analyse.
The aim of this thesis is to analyse how thinning on Järvselja experimental plot has affected Scots pine radial growth. The samples were collected in 2011, during the project of Environment Investment Centre’s “Ascertainment of stand disturbances using dendrochronological methods”. The experimental plot is divided into three separate areas: first area was heavily thinned, on second area moderate thinning was made and the third area was control area where no thinning was made. Thinning effect on radial growth was analysed graphically using Relative Growth Change (GC) and Superposed Epoch Analysis (SEA) methods with Excel and R tools. In results we see that thinning had positive impact on scots pine radial growth. Calculated mean diameter increments and ring widths were bigger on heavily thinned area and the smallest on control area. Using relative growth change we found relative increment changes in percentages. Relative increment changes were the biggest on heavily thinned area and growth releases after thinning were revealed. On moderately thinned area the growth change is slightly smoother and after the last thinning no bigger fluctuations can be seen. The most uniform growth had the control area trees. Bigger increment growth change percentages were seen in previous years and that phenomenon occurred on all three areas. Despite the fact that on control area no thinning was made, all three areas had similarities in their growth trends, which indicates on another growth limiting factor. With superposed epoch analysis we analysed how thinning reflects in increment index series 5 years before thinning and 5 years after thinning. Positive results were found only heavily thinned area. It showed us that, on first and second year after thinning increment changes were positive. On moderately thinned area no remarkable changes were found and on control area we did not have event to analyse.
Kirjeldus
Bakalaureusetöö
Loodusvarade kasutamise ja kaitse õppekaval
Märksõnad
bakalaureusetööd, harvendusraie, radiaalkasv, raiete mõjud, häiringud, kattuvad järgud, analüüs, Järvselja