Puistu piirtiheduse mudelite hindamine metsa kasvukäigu püsiproovitükkide andmeil
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Kuupäev
2022
Kättesaadavus
06.09.2022
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Metsa modelleerimise eesmärgiks on läbi aastate olnud täpsemate puistumudelite
väljatöötamine, mis annaksid puistu seisukorra hindamisel võimalikult reaalsusele lähedase
tulemuse ja aitaksid kaasa metsakorralduslike tööde täpsemale planeerimisele. Oluline
näitaja on puistu tihedus, mille iseloomustamiseks kasutatakse Eestis Metsa korraldamise
juhendi põhjal täiust. Käesoleva bakalaureusetöö eesmärgiks on võrrelda erinevate Eestis
üldtuntud kasvukäigutabelite kaudu tuletatud mudelite asjakohasust Eesti tingimustes
kasvavate männikute, kuusikute ja kaasikute kasvukäigu kirjeldamisel.
Töö käigus uuriti puistu hõreduse ja diameetri vahelist seost erineva boniteediga puistude
näitel erinevate kasvukäigutabelite andmetel. Samuti võrreldi erinevate kasvukäigutabelite
autorite andmetel koostatud mudeleid Eesti metsa kasvukäigu püsiproovitükkide
mõõtmisandmetega ning kontrolliti, kas metsa korraldamise juhendi põhjal kasutatava
täiuse asendamine Artur Nilsoni puistu piirhõredust kasutava puude arvu suhtega oleks
võimalik.
Selgus, et puistu hõreduse ja diameetri vaheline seos kasvukäigutabelite andmetel on
lineaarne ning proovitükkide mõõtmisandmetega ühildub kõige paremini Tjurini
kasvukäigutabelite andmetel koostatud M4 mudel. Puude arvu suhe on puistu kasvukäigu
proovitükkide andmeil sobiv alternatiiv praegu kasutatavale täiusele.
The aim of forest modeling has been through years to develope more accurate stand models, which would give the most realistic result for the evaluation of stand condition and would help to plan forest management more accurately. Stand density is an important factor. In Estonian forest survey guidelines stand density is prescribed by relative density. The aim of this Bachelor's thesis is to evaluate if models based on yield tables by different authors are reliable sources for describing the growth of pine, spruce and birch stands in Estonia. In the course of research the relationship between stand density and diameter at stands with different site index values based on the data of yield tables was investigated. The models compiled based on the data of yield tables by different authors were compared with the measurement data from The Network of permanent forest growth plots in Estonia. It was checked if it would be possible to replace relative density as the factor of density with the relationship between the number of trees on forest growth plots and the number of trees according to the yield table. As it came out according to the data from the yield tables the relationship between stand density and diameter is linear. The model M4 based on the data of Tjurin’s yield tables described the data from the network of permanent forest growth plots most accurately. The relationship between the number of trees on forest growth plots and the number of trees according to the yield table compensated for the inaccurances caused by relative density.
The aim of forest modeling has been through years to develope more accurate stand models, which would give the most realistic result for the evaluation of stand condition and would help to plan forest management more accurately. Stand density is an important factor. In Estonian forest survey guidelines stand density is prescribed by relative density. The aim of this Bachelor's thesis is to evaluate if models based on yield tables by different authors are reliable sources for describing the growth of pine, spruce and birch stands in Estonia. In the course of research the relationship between stand density and diameter at stands with different site index values based on the data of yield tables was investigated. The models compiled based on the data of yield tables by different authors were compared with the measurement data from The Network of permanent forest growth plots in Estonia. It was checked if it would be possible to replace relative density as the factor of density with the relationship between the number of trees on forest growth plots and the number of trees according to the yield table. As it came out according to the data from the yield tables the relationship between stand density and diameter is linear. The model M4 based on the data of Tjurin’s yield tables described the data from the network of permanent forest growth plots most accurately. The relationship between the number of trees on forest growth plots and the number of trees according to the yield table compensated for the inaccurances caused by relative density.
Kirjeldus
Bakalaureusetöö
Metsanduse õppekaval
Märksõnad
bakalaureusetööd, piirtihedus, hõredus, modelleerimine, kasvukäigutabel