Püsiproovitükkide andmetel üksikpuude vanuste täpsustamine dendrokronoloogiliste meetoditega
Laen...
Kuupäev
2023
Kättesaadav alates
06.09.2023
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Puu vanuse määramine välitingimustes on üldiselt problemaatiline, suure veaga
metsaregistri andmetes. Usaldusväärsete metsamudelite loomiseks on vajalik ka
kontrollitud algandmestik, mille põhjal koostada näiteks kõrguse-vanuse mudeleid, milleks
on puistu kasvukäigu püsiproovitükkide andmestik. Dendrokronoloogiliste meetoditega on
võimalik tuvastada täpne kalendriaasta, mil aastarõngas on moodustunud. Käesolevas
lõputöös analüüsitakse juurdekasvupuuriga võetud puursüdamikelt aastarõngaste
tuvastamisega seotud probleeme (säsi puudu, mädanik). Samuti, kui palju erinevad
puurproovilt dateeritud metsaelemendi ja metsaregistri vanus. Varasemalt on teada, et
metsaregistri vanused ei pruugi olla usaldusväärsed metsamudelite jaoks, sest need on
enamasti alla hinnatud metsakorraldajate poolt. Lisaks analüüsiti tunnuste vahelisi seoseid
(vanuse ja puuliigi, kasvukohatüübi, diameetri, kõrguse). Töös kasutati 64 puurproovi
andmeid, mis koguti 39 puistu kasvukäigu püsiproovitükilt Jõgeva- ja Tartumaalt.
Juurdekasvupuuriga kogutud puurproovidelt loeti laboris aastarõngad, et täpsustada puude
vanuseid ja võrreldi neid vanuseid metsaregistri vanustega. Samuti tuvastati, millised
proovid olid terved (säsiga) või ilma säsita (vajalik interpreteerida puuduvad aastarõngad)
ning kahjustatud (mädanikuga). Puu rinnaskõrguselt (D1,3) saadud proovidele
interpreteeriti vanus juurekaelale, et võrrelda metsaregistri metsaelemendi vanusega. Tööks
kogutud proovidest õnnestus saada ainult 22% terveid proove, mis olid koos säsiga, vanuse
dateerimiseks. 66% proovidest olid küll terved, kuid neil puudus säsi, mistõttu tuli neil
proovidel interpreteerida puudu olevate aastarõngaste arv. Antud töös leiti, et
puursüdamikult dateeritud ja metsaregistri antud metsaelemendi vanused erinesid.
Keskmiselt erinesid vanused üle kogu andmestiku 7,1 aastat. Enamasti, 62,5% juhtudest,
oli metsakorralduse vanus väiksem (alla hinnatud), kui puursüdamikelt täpsustatud vanus,
samas 37,5% oli metsaregistri vanus suurem (üle hinnatud). Statistiliselt oluline seos ilmnes
ka vanuse ja puuliigi, kasvukohatüübi, kõrguse ning diameetri vahel. Kindlasti oleks
vajalikud jätku-uuringuid täiustatud metoodikaga, et täpsustada puistu vanust
suuremahulisemal andmestikul eri puuliikide, kasvukohatüüpide, looduslikes ja/või
kultuurpuistutes, võrrelda aastarõngaste arvu rinnaskõrgusel ja juurekaelal.
Dendrokronoloogilised meetodid oleks selliseks uuringuks kõige usaldusväärsemad.
Determining the age of a tree in outdoor conditions is problematic, with a large error in the data of forest register. In order to create reliable forest models, it is also necessary to have controlled initial data, with those data modeling height can be composed, which is a database of permanent forest growth plots. By using dendroconological methods, it is possible to identify the exact calendar year when exactly the annual ring was formed. The aim of this thesis is to analyse problems (missing core, rot) related to the identification of annual rings from increment cores taken with an increment borers. Also, how much the age differs of the forest element dated from the increment core samples and the forest register. It is already known that forest register ages may not be reliable for forest models, because they are mostly underestimated by forest managers. In addition, relationships between characteristics were analyzed (age and tree species, forest site type, diameter, height). In this study there were used 64 increament core samples, which were collected from 39 forest growth plots in Jõgeva County and Tartu County. In the laboratory, annual rings were measured to determine the ages of the trees and were compared with the ages of the forest register. It was also identified which samples were whole (with pith) or without pith (missing annual rings need to be interpreted) and damaged (with rot). For the samples obtained from tree breast height (D1.3), the age of the stem base was interpreted to compare it with the age of the forest element of the forest register. There were only 22% whole samples, which were with the pith, for age dating. 66% of the samples were almost whole, but they missed the pith, so the number of missing annual rings had to be interpreted on these samples. In this study, it was found that the age dated from the increment cores and the forest elements age given in the forest register differed. On average, ages differed by 7.1 years across the entire dataset. 62.5% of the cases, the age of the forest management was lower (underestimated) than the age specified from the increment cores. However, 37.5% of the cases, the age of the forest register was higher (overestimated). A statistically significant relationship was also revealed between age and tree species, forest site type, height and diameter. It is definitely necessary to do further research with improved techniques to specify the number of annual rings at breast height and at the stem base, use different tree species and forest site types and also natural and/or cultured stands on a larger scale database. Dendrochronological methods would be the most reliable for such a study.
Determining the age of a tree in outdoor conditions is problematic, with a large error in the data of forest register. In order to create reliable forest models, it is also necessary to have controlled initial data, with those data modeling height can be composed, which is a database of permanent forest growth plots. By using dendroconological methods, it is possible to identify the exact calendar year when exactly the annual ring was formed. The aim of this thesis is to analyse problems (missing core, rot) related to the identification of annual rings from increment cores taken with an increment borers. Also, how much the age differs of the forest element dated from the increment core samples and the forest register. It is already known that forest register ages may not be reliable for forest models, because they are mostly underestimated by forest managers. In addition, relationships between characteristics were analyzed (age and tree species, forest site type, diameter, height). In this study there were used 64 increament core samples, which were collected from 39 forest growth plots in Jõgeva County and Tartu County. In the laboratory, annual rings were measured to determine the ages of the trees and were compared with the ages of the forest register. It was also identified which samples were whole (with pith) or without pith (missing annual rings need to be interpreted) and damaged (with rot). For the samples obtained from tree breast height (D1.3), the age of the stem base was interpreted to compare it with the age of the forest element of the forest register. There were only 22% whole samples, which were with the pith, for age dating. 66% of the samples were almost whole, but they missed the pith, so the number of missing annual rings had to be interpreted on these samples. In this study, it was found that the age dated from the increment cores and the forest elements age given in the forest register differed. On average, ages differed by 7.1 years across the entire dataset. 62.5% of the cases, the age of the forest management was lower (underestimated) than the age specified from the increment cores. However, 37.5% of the cases, the age of the forest register was higher (overestimated). A statistically significant relationship was also revealed between age and tree species, forest site type, height and diameter. It is definitely necessary to do further research with improved techniques to specify the number of annual rings at breast height and at the stem base, use different tree species and forest site types and also natural and/or cultured stands on a larger scale database. Dendrochronological methods would be the most reliable for such a study.
Kirjeldus
Bakalaureusetöö
Metsanduse õppekaval
Märksõnad
bakalaureusetööd, aastarõngad, dendrokronoloogia, metsaregister, vanus, püsiproovitükid, Roheline Ülikool (töö toetab EMÜ Rohelise Ülikooli põhimõtteid), keskkonnateadvus, keskkonnaharidus