Majandamisviiside mõju põlengujärgse metsa uuenemisele Vihterpalu katsealade näitel
Laen...
Kuupäev
2012
Kättesaadav alates
ainult raamatukogus, only in library
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Käesolevas töös on analüüsitud Eestis Vihterpalu katsealade põlengujärgse metsa
uuenemist. Kuna Vihterpalu aladel on põlengud sagedased ja puuduvad selged
soovitused põlenud metsaalade uuendamiseks Eestis, on teema aktuaalne. Magistritöö
eesmärgiks on uurida erinevate majandamisviiside mõju põlengujärgsele metsaalade
uuenemise arvukusele ja kõrguskasvule.
Vihterpalusse on rajatud põlengualade uuenemise jälgimiseks kokku 24 proovitükki
(20x40 m), millest igal on kaks alamproovitükki suurusega 2,5x40 m puittaimede
loodusliku uuenduse mõõtmiseks. Alasid majandati põlengujärgselt erinevalt: põlenud ja
koristatud (BC), põlenud ja koristamata (BU), põlenud ja koristamata vana puistu
(BUO), põlenud ja koristamata elusate puudega puistu (BUA) ja kontrollalad (CO) ilma
põlenguta aladele.
Leiti, et Vihterpalu põlengualadel uuenesid kask (Betula spp.), harilik mänd (Pinus
sylvestris L.) ja harilik haab (Populus tremula L.). Erinevad majandamisviisid mõjutavad
nende liikide looduslikku uuenemist ning uuenduse kasvu põlengualadel. Selgus, et
üldiselt on uuenemise arvukus madalam koristatud aladel (BC) võrreldes koristamata
aladega (BU, BUO ja BUA). Seda eriti vahetult peale põlenguid. Koristamata aladel on
kase uuenemine algusaastatel edukam. Et vältida tuleohtu puhtmännikutes tuleks jätta
koristamata alasid looduslikule uuenemisele, kuna parema kõrguskasvuga ja arvukalt
uuenev kask vähendab seal tuleohtu. Seega tagab metsade kiirema loodusliku uuenemise
alade koristamata jätmine, mis tagab ka suurema bioloogilise mitmekesisuse. Kuna aga
BC aladel on kõikide liikide kõrguskasv suurem paremate valgustingimuste tõttu, võiks
osadel aladel raiet mõne aasta võrra edasi lükata ja teha seda lumerohkel talvel. Kuna
bioloogiline mitmekesisus on otseselt seotud surnud puiduga ei tohiks kõiki alasid
koristada. Mänd ja haab ei uuene vahetult peale põlengut vaid alles 3-10 aasta möödudes.
Peale esimese aastakümne möödumist mänd asendab puistus lehtpuud, kuna on sellistes
tingimustes paremini kohastunud. Kontrollaladel esines uuenemist minimaalselt, mis
näitab, et suktsessioon ilma tule häiringuta toimub Vihterpalu aladel väga aeglaselt ning
põlengud on ökosüsteemi lahutamatu osa.
Uurimuse jätkamine asjakohane, et anda veelgi põhjendatumaid soovitusi põlenujärgsete
metsade majandamiseks ja leida põhjendusi eeldustele, mis antud töö tulemustele lisaks
tekkisid.
Regeneration after forest fires in Estonia Vihterpalu, has been analyzed. Since fire is frequent in Vihterpalu and there is no clear advice on how to manage burnt areas in Estonia, the topic is actual. The objective of the master thesis is to investigate the influence of different management regimes on the regeneration and height of trees after fire. There are total 24 sample plots (20x40 m) created on the area of Vihterpalu to monitor the regeneration, in which each of them has two sub-plots on the size of 2,5x40 m for the mensuration of natural regeneration. Areas were managed differently: burned and cleaned (BC), burned and un-cleaned (BU), burned and un-cleaned with old stand (BUO), burned and un-cleaned with trees alive (BUA) and control plots without fire (CO). It was found that in Vihterpalu fire damaged area birch (Betula spp.), Scots pine (Pinus sylvestris L.) and European aspen (Populus tremula L.) regenerated. Different management regimes have an effect on the natural regeneration and the growth of these species. It was found that generally regeneration is lower in burned and cleaned areas (BC) compared to burned un-cleaned areas (BU, BUO and BUA). Especially right after the fire. In un-cleaned areas the regeneration of birch was better on the first years. To suppress fire in pure pine stands the un-cleaned areas should be left for natural regeneration. Birch, which has better height growth and regenerates numerously, lowers the risk of fire there. Therefore leaving some areas un-cleaned guarantees faster natural regeneration, which guarantees more biodiversity. As the growth of height in BC areas is better for all the species due to better light conditions, some areas should be cut. The cutting should be executed few years after the fire and with heavy snow. As the biodiversity is directly connected to the occurrence of dead wood, all the areas should not be cut. Pine and aspen do not start to regenerate immediately after fire, it takes approximately 3-10 years. After the first decade pine starts to dominate and replaces deciduous trees. Regeneration was minimal in the control (CO) areas, which shows that the succession without fire disturbance in Vihterpalu areas is very slow and fires are normal and inseparable part of the ecosystem. The continuation of this research is relevant to give more well-grounded advice on how to manage forests after fire disturbance and find reasons on the hypothesis that came up in addition to the results of this thesis.
Regeneration after forest fires in Estonia Vihterpalu, has been analyzed. Since fire is frequent in Vihterpalu and there is no clear advice on how to manage burnt areas in Estonia, the topic is actual. The objective of the master thesis is to investigate the influence of different management regimes on the regeneration and height of trees after fire. There are total 24 sample plots (20x40 m) created on the area of Vihterpalu to monitor the regeneration, in which each of them has two sub-plots on the size of 2,5x40 m for the mensuration of natural regeneration. Areas were managed differently: burned and cleaned (BC), burned and un-cleaned (BU), burned and un-cleaned with old stand (BUO), burned and un-cleaned with trees alive (BUA) and control plots without fire (CO). It was found that in Vihterpalu fire damaged area birch (Betula spp.), Scots pine (Pinus sylvestris L.) and European aspen (Populus tremula L.) regenerated. Different management regimes have an effect on the natural regeneration and the growth of these species. It was found that generally regeneration is lower in burned and cleaned areas (BC) compared to burned un-cleaned areas (BU, BUO and BUA). Especially right after the fire. In un-cleaned areas the regeneration of birch was better on the first years. To suppress fire in pure pine stands the un-cleaned areas should be left for natural regeneration. Birch, which has better height growth and regenerates numerously, lowers the risk of fire there. Therefore leaving some areas un-cleaned guarantees faster natural regeneration, which guarantees more biodiversity. As the growth of height in BC areas is better for all the species due to better light conditions, some areas should be cut. The cutting should be executed few years after the fire and with heavy snow. As the biodiversity is directly connected to the occurrence of dead wood, all the areas should not be cut. Pine and aspen do not start to regenerate immediately after fire, it takes approximately 3-10 years. After the first decade pine starts to dominate and replaces deciduous trees. Regeneration was minimal in the control (CO) areas, which shows that the succession without fire disturbance in Vihterpalu areas is very slow and fires are normal and inseparable part of the ecosystem. The continuation of this research is relevant to give more well-grounded advice on how to manage forests after fire disturbance and find reasons on the hypothesis that came up in addition to the results of this thesis.
Kirjeldus
Märksõnad
metsapõlengud, looduslik uuenemine, põlengualade majandamine, magistritööd