Puistute tootlikkus kuuse-kase segametsas ja nende puhtpuistutes
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Kuupäev
2024
Kättesaadavus
03.09.2024
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Viimaste aastakümnete jooksul on atmosfääris kasvuhoonegaaside, eelkõige CO2 osakaal oluliselt tõusnud, mille tagajärjel on kliimamuutuste tulemusena keskkonnaseisund halvenenud. Kliimamuutuste leevendamiseks on oluline vähendada fossiilse süsiniku emissioonide osakaalu ning suurendada taastuvate materjalide (nt puit) kasutamist ning samuti suurendada metsade süsiniku sidumisvõimet. Puhtpuistute asendamine segametsadega on üks võimalik meetod tõstmaks metsaökosüsteemide vastupanu võimet kliimamuutustele, kuid seni on vähe uuringuid, mis võrdlevad istutatud puht- ja segapuistute produktiivsust ja mõju mullaomadustele.
Bakalureusetöö eesmärgiks oli hinnata hariliku kuuse ja arukase puhtpuistute ning kuuse-kase segametsa mõju produktiivsusele ja mulla keemilistele omadustele ca 20 aasta vanustes istutatud puistutes. Välitööde käigus mõõdeti kõigilt kolmelt puistutüübilt kümne proovitüki puude kasvuandmed ehk rinnasdiameeter ja kõrgus ning koguti mullaproovid pH, süsiniku (C), lämmastiku (N), fosfori (P) ja kaaliumi (K) määramiseks. Kasvuandmete põhjal arvutati puistutüüpide tagavarad ning keskmised aastased juurdekasvud. Andmetöötluse läbiviimiseks kasutati programmi MS Excel ning andmete statistiline analüüs teostati Rstudio programmis.
Tulemustes selgus, et kuuse puhtpuistu kogutootlikkuse ja kasvava metsa aastane keskmine juurdekasv ning tagavara on oluliselt suurem teistest puistutüüpidest. Kase kasvunäitajate põhjal selgus, et vähenenud liigisisese konkurentsi tulemusena oli kaskede kasv parem segametsas. Mulla keemilised omadused ei erinenud sega- ja puhtpuistute vahel. Kokkuvõttes võib tulemuste põhjal väita, et kuuse puhtpuistu on antud vanuses tootlikum kui segamets ja kase puhtpuistu. Kiirekasvuline pioneerpuuliik (arukask) võidab kasvus segametsas, sest väheneb liigisisene konkurents. Seevastu aeglasema kasvuga puuliigile (harilik kuusk) on konkurents segametsas suurem ning seega kaotab ka kasvus.
During the last decades, the proportion of greenhouse gases, especially CO2, has significantly increased in the atmosphere, leading to deterioration in envrionmental conditions due to climate change. To mitigate climate change, it is important to reduce the share of fossil based carbon emissions and increase the use of renewable materials (e.g. timber) and also increase the carbon sequestration capacity of forests. Replacing pure stands with mixed forests is one possible method to increase the resilience of forest ecosystems to climate change, but so far there are few studies that compare the productivity and impact on soil properties of planted pure and mixed stands. The aim of this bachelor´s thesis was to evaluate the effect of pure stands of Norway spruce and silver birch and a mixed spruce-birch forest on the productivity and chemical properties of the soil in approximately 20-year-old planted stands. During the field inventory, the growth data (diameter at breast height and height) of ten plots from all three stand types were measured and soil samples were collected to determine pH, carbon (C), nitrogen (N), phosphorus (P) and potassium (K). On the basis of the growth data, the standing volume and mean annual increment of stand types were calculated. The MS Excel program was used for data processing, and the statistical analysis of the data was tested in the Rstudio program. The results revealed that the mean annual increment and the total volume productivity of the spruce monoculture is significantly higher than other stand types. Based on birch growth indicators, it was revealed that as a result of reduced intraspecific competition, the growth indicators were greater in mixed forests. Soil chemical properties did not differ between mixed and pure stands. In summary, based on the results, it can be stated that a pure stand of spruce is more productive at the given age than a mixed forest and a birch pure stand. The fast-growing pioneer tree species (silver birch) wins in growth in a mixed forest because intraspecific competition decreases. On the other hand, the slower-growing tree species (Norway spruce) has greater competition in a mixed forest and therefore loses in growth.
During the last decades, the proportion of greenhouse gases, especially CO2, has significantly increased in the atmosphere, leading to deterioration in envrionmental conditions due to climate change. To mitigate climate change, it is important to reduce the share of fossil based carbon emissions and increase the use of renewable materials (e.g. timber) and also increase the carbon sequestration capacity of forests. Replacing pure stands with mixed forests is one possible method to increase the resilience of forest ecosystems to climate change, but so far there are few studies that compare the productivity and impact on soil properties of planted pure and mixed stands. The aim of this bachelor´s thesis was to evaluate the effect of pure stands of Norway spruce and silver birch and a mixed spruce-birch forest on the productivity and chemical properties of the soil in approximately 20-year-old planted stands. During the field inventory, the growth data (diameter at breast height and height) of ten plots from all three stand types were measured and soil samples were collected to determine pH, carbon (C), nitrogen (N), phosphorus (P) and potassium (K). On the basis of the growth data, the standing volume and mean annual increment of stand types were calculated. The MS Excel program was used for data processing, and the statistical analysis of the data was tested in the Rstudio program. The results revealed that the mean annual increment and the total volume productivity of the spruce monoculture is significantly higher than other stand types. Based on birch growth indicators, it was revealed that as a result of reduced intraspecific competition, the growth indicators were greater in mixed forests. Soil chemical properties did not differ between mixed and pure stands. In summary, based on the results, it can be stated that a pure stand of spruce is more productive at the given age than a mixed forest and a birch pure stand. The fast-growing pioneer tree species (silver birch) wins in growth in a mixed forest because intraspecific competition decreases. On the other hand, the slower-growing tree species (Norway spruce) has greater competition in a mixed forest and therefore loses in growth.
Kirjeldus
Bakalaureusetöö
Metsanduse õppekaval
Märksõnad
bakalaureusetööd, puistute tootlikkus, segamets, puhtpuistu, harilik kuusk, arukask