Wood formation in pedunculate oak and its relation with climatic factors in Latvia
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Latvijas Universitāte
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eng
Abstract
Šajā darbā ir analizēta parastā ozola (Quercus robur L.) augšanas saistība ar klimatiskajiem faktoriem Latvijā (43 vietas), izmantojot dendrohronoloăijas un dendroekoloģijas metodes. Klimata ietekmes novērtējumam, izmantoja divus atšķirīgus gadskārtu mērījumus: gadskārtu platumu un pavasara koksnes traheju dobumu laukumu. Ozola augšana uzrādīja atšķirības gar austrumu-rietumu gradientu saistībā ar klimata kontinentalitāti. Balstoties uz šo gradientu Latvijas teritoriju var iedalīt divās daļās (rietumu un austrumu reģionā). Gadskārtu platumu rietumu reģionā, galvenokārt, ietekmēja pavasara un vasaras gaisa temperatūra, bet austrumu reģionā klimatisko faktoru, kas ir saistīti ar sausumu vasarā, ietekme bija visizteiktākā. Pavasara koksnes traheju dobumu laukumu noteica miera perioda un agra pavasara gaisa temperatūra. Pēdējo 30 gadu laikā krasas izmaiņas gan gadskārtu platumā, gan pavasara koksnes traheju laukumā, ir notikušas Latvijas austrumu reģionā, un to cēlonis ir saistāms ar ekstrēmiem laika apstākļiem. Atslēgas vārdi: parastais ozols, klimats, gadskārtu platums, pavasara koksnes traheju izmērs, Latvija.
The study was conducted at the University of Latvia, Faculty of Biology during 2008–2012. In this study growth of pedunculate oak (Quercus robur L.) in relation to climatic factors in Latvia (43 sites) was investigated by dendrochronological and dendroecological methods. Effect of climatic factors on two tree-ring proxies: tree-ring width and earlywood vessel lumen area was evaluated. Growth of oak in Latvia differed across an East-West gradient according to continentality of climate and two regions of Latvia (western and eastern) were distinguished. Tree-ring width in western Latvia is mainly affected by spring and summer temperature, while in eastern region the effect of climatic factors related with drought in summer was more expressed. Earlywood vessel lumen area is controlled by temperature in the dormant period and early spring. During past 30 years, changes in both proxies occurred in eastern region, which were likely caused by climatic extremes. Keywords: pedunculate oak, climate, tree-ring width, earlywood vessel size, Latvia.
The study was conducted at the University of Latvia, Faculty of Biology during 2008–2012. In this study growth of pedunculate oak (Quercus robur L.) in relation to climatic factors in Latvia (43 sites) was investigated by dendrochronological and dendroecological methods. Effect of climatic factors on two tree-ring proxies: tree-ring width and earlywood vessel lumen area was evaluated. Growth of oak in Latvia differed across an East-West gradient according to continentality of climate and two regions of Latvia (western and eastern) were distinguished. Tree-ring width in western Latvia is mainly affected by spring and summer temperature, while in eastern region the effect of climatic factors related with drought in summer was more expressed. Earlywood vessel lumen area is controlled by temperature in the dormant period and early spring. During past 30 years, changes in both proxies occurred in eastern region, which were likely caused by climatic extremes. Keywords: pedunculate oak, climate, tree-ring width, earlywood vessel size, Latvia.