Hariliku kuuse rinnasdiameetri juurdekasvu modelleerimine jänesekapsa kasvukohatüübis
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Kuupäev
2015
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Teatava tinglikusega võib kogu metsanduslikku uurimistegevust vaadelda mudelite
koostamisena, et uurida metsa ja sellega piirnevaid nähtusi, nende kontrollimist ja
juurutamist. Järjest laiemalt võetakse kasutusele kasvusimulaatoreid, mis prognoosivad puude
kasvu üksikpuutasemel, kuna sellised mudelid on paindlikumad ning võimaldavad arvestada
ka segapuistutega. Töö eesmärk on uurida hariliku kuuse juurdekasvu jänesekapsa
kasvukohatüübis üksikpuu tasandil. Töös kasutatakse püsiproovitükkide võrgusiku andmeid,
millest on välja eraldatud jänesekapsa kasvukohatüüp, kus kasvab kuuski, sõltumata sellest,
kas kuusk on peapuuliik või mitte. Täpsema tulemuse saamiseks tuli korrigeerida perioodilist
juurdekasvu täpselt viieaastasele tsüklile. Diameetri juurdekasvumudelite hindamiseks
kasutati Akaike informatsioonikriteeriumit. Mudeli valmimisel selgus, et ülakõrguse
kasutamine on õigustatud, sest annab parema tulemuse kui tavaline boniteerimismudel.
Parimaks osutus mudel, mis sisaldab järgmisi tunnuseid: suhteline diameeter, diameetri
juurdekasv, puuliik, täius ja ülakõrgusindeks. Eestis puuduvad mudelid, mis hindavad
kuuskede juurdekasvu segapuistutes. Käesolev töö keskendub ainult jänesekapsa
kasvukohatüübile, kuid edaspidi oleks mõttekas teha mudeleid ka teistele kasvukohatüüpidele.
For forest management planning and assessment of wood production, precise estimation of tree growth is needed. Growth simulators are more and more widely used, which prognoses are based on individual tree growth modelling. Such models are more flexible and can be applied for mixed stands. In Estonia growth traditionally is estimated, based on yield tables, which are static models . More detailed predictions can be achieved when stand growth is estimated based on individual tree information. In Estonia, there is a lack of models which could estimate growth of Norway spruce in mixed stands. The aim of this study was to develope a tree-level distance independent radial growth model, which could be used to predict increment of individual Norway spruce trees on Oxalis site type. Tree-level data from forest permanent sample plot network in Estonia were used. Since Norway spruce is not the only dominant tree species on this site type, radial growth for other most common tree species were also considered. For more accurate results, periodic diameter increment was adjusted into exact five-year intervals. Model fit was estimated based on Akaike information criteria. Stand top height was better predictor compared to average stand height. The final model describing periodic radial increment included the following dependent variables: relative diameter, tree species, relative density and top height index. The developed model can be used for diameter increment prediction of trees growing on Oxalis site type. Its suitability for other forest site types shuld be tested.
For forest management planning and assessment of wood production, precise estimation of tree growth is needed. Growth simulators are more and more widely used, which prognoses are based on individual tree growth modelling. Such models are more flexible and can be applied for mixed stands. In Estonia growth traditionally is estimated, based on yield tables, which are static models . More detailed predictions can be achieved when stand growth is estimated based on individual tree information. In Estonia, there is a lack of models which could estimate growth of Norway spruce in mixed stands. The aim of this study was to develope a tree-level distance independent radial growth model, which could be used to predict increment of individual Norway spruce trees on Oxalis site type. Tree-level data from forest permanent sample plot network in Estonia were used. Since Norway spruce is not the only dominant tree species on this site type, radial growth for other most common tree species were also considered. For more accurate results, periodic diameter increment was adjusted into exact five-year intervals. Model fit was estimated based on Akaike information criteria. Stand top height was better predictor compared to average stand height. The final model describing periodic radial increment included the following dependent variables: relative diameter, tree species, relative density and top height index. The developed model can be used for diameter increment prediction of trees growing on Oxalis site type. Its suitability for other forest site types shuld be tested.
Kirjeldus
Märksõnad
puistud, kuusk, kasv, modelleerimine (teadus), kasvukohatüübid, magistritööd