Varisevood erinevates lehtpuupuistute metsaökosüsteemides
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Kuupäev
2016
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Märkimisväärne osa süsinikuvarudest on seotud metsaökosüsteemides ning süsiniku sidumine
metsade puitsesse biomassi ja metsamulda on põhiline kliimamuutuste vähendaja. Antud
bakalaureusetöö keskendub ühe vähem uuritud metsa süsinikuvoo – metsa varisevoo
uurimisele erinevates metsaökosüsteemides.
Käesolev bakalaureusetöö põhineb 5 arukase (Betula pendula), 5 sookase (Betula pubescens)
ja 6 halli lepa (Alnus incana) puistu maapealse metsavarise voo vaatlusandmetel aastatel
2009–2015. Uuritavad puistud asuvad Lõuna-Eestis: Põlva, Tartu ja Valga maakonnas.
Bakalaureusetöö eesmärgiks oli analüüsida arukase, sookase ja halli lepa puistute
variseproduktsiooni ja sesoonset dünaamikat. Lisaks uurida võimalikke seoseid puistu
maapealse variseproduktsiooni ja puistu vanuse ning ilmastikutingimuste vahel.
Uurimuses ilmnes, et puistu variseproduktsioon ja koostis varieeruvad suuresti erineva vanuse
ja peapuuliigiga puistutes. Aastane varise hulk 14- kuni 65-aastastes arukaasikutes jäi
vahemikku 2,33–3,61 t ha-1
, 15- kuni 70-aastastes sookaasikutes 3,03–4,17 t ha-1
ja 8- kuni
40-aastastes hall-lepikutes 1,77–5,35 t ha-1
. Varise hulk oli suurim keskealistes puistutes, kus
võrastik oli liitunud ja juurdekasv maksimaalne. Varise sesoonses dünaamikas eristus selgelt
sügisene maksimum, mis on omane lehtpuudele, arvestades, et suurema enamuse varisest
moodustavad lehed.
Täiendavate vaatlusandmete lisandumisel on oodata loodud varisevoo mudelite statistilise
usaldusväärsuse paranemist, aidates paremini mõista Eesti metsade süsinikubilanssi.
A significant portion of carbon stocks are located in forest ecosystems. Carbon fluxes accumulated in woody biomass and forest soils are mitigating climate change. Present study focuses on litterfall and its dynamics, which is one of the least researched carbon fluxes in forests. The study is based on litterfall observations in 5 silver birch (Betula pendula), 5 downy birch (Betula pubescens) and 6 gray alder (Alnus incana) stands. In addition to litterfall dynamics the changes in litter quantity in relation to stand age and weather conditions were studied. The results showed a connection between stand age and litter production as well as litter composition. Total amount of litter collected in a time period of one year was 2,33– 3,61 t ha-1 in silver birch stands between ages of 14–65; 3,03–4,17 t ha-1 in downy birch stands aged 15– 70 years and 1,77–5,35 t ha-1 in grey alder stands aged 8–40 years. The amount of litter was highest during the time of canopy closure where stand increment was the highest. There was a clear maximum in seasonal litterfall dynamics in autumn, when it is typical for deciduous tree species to drop a large ratio of leaf litter. The reliability of current modules regarding litter fluxes is expected to improve with additional observation information in the future and shall assist in better understanding forest carbon cycle in regards to climate change.
A significant portion of carbon stocks are located in forest ecosystems. Carbon fluxes accumulated in woody biomass and forest soils are mitigating climate change. Present study focuses on litterfall and its dynamics, which is one of the least researched carbon fluxes in forests. The study is based on litterfall observations in 5 silver birch (Betula pendula), 5 downy birch (Betula pubescens) and 6 gray alder (Alnus incana) stands. In addition to litterfall dynamics the changes in litter quantity in relation to stand age and weather conditions were studied. The results showed a connection between stand age and litter production as well as litter composition. Total amount of litter collected in a time period of one year was 2,33– 3,61 t ha-1 in silver birch stands between ages of 14–65; 3,03–4,17 t ha-1 in downy birch stands aged 15– 70 years and 1,77–5,35 t ha-1 in grey alder stands aged 8–40 years. The amount of litter was highest during the time of canopy closure where stand increment was the highest. There was a clear maximum in seasonal litterfall dynamics in autumn, when it is typical for deciduous tree species to drop a large ratio of leaf litter. The reliability of current modules regarding litter fluxes is expected to improve with additional observation information in the future and shall assist in better understanding forest carbon cycle in regards to climate change.
Kirjeldus
Märksõnad
metsakõdu, lehtpuud, puistud, metsaökosüsteemid, süsinikuringe, bakalaureusetööd