Krajsky Urad Stredoceskeho Kraje

Prague, Czech Republic

Krajsky Urad Stredoceskeho Kraje

Prague, Czech Republic
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Bednarova E.,Mendel University in Brno | Kucera J.,Turisticka 5 | Merklova L.,Krajsky Urad Stredoceskeho Kraje
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

A phenological study on the onset and duration of particular phenological stages of European beech (Fagus sylvatica L.) was carried out using sample trees growing in a research area of the Faculty of Forestry and Wood Technology, MENDELU Brno for a period of 17 years (1991-2007). The paper describes the onset and duration of particular phenological stages depending on effective temperatures. In spring phenological stages, the high dependence was proved on air temperatures. To evaluate temperature requirements of studied species the cumulative sum of temperatures which activated the beginning of a respective phenological stage was used. It is evident that the onset and the course of particular phenological stages were very variable being subject to the effect of temperature changes, particularly in the spring season. In recent years, the earlier onset is noted of spring phenological stages and the length of their duration shortens. Effects of temperature on the onset and duration of the stage of budbreak and the beginning of foliage became evident in European beech most markedly. 2007 was a very extreme year from the aspect of the early onset of spring vegetative phenological stages. In that year, a marked shift was noted in the onset of particular staged as compared to previous years. To specify phenological observations, records of phenological data of a camera placed in the central part of a crown were used. Results obtained show that some spring phenological stages take only several hours, which corresponds with higher temperatures during spring months in last years. In the area described, higher temperatures were measured even in autumnal months as compared with a long-term average. Owing to high temperatures in the pre-dormancy period, the extension of a growing season occurs and thus also shortening the dormancy playing an irreplaceable role in forest trees. Shortening the dormancy can result in the disturbance of physiological processes and subsequently the decline of trees.


Bednarova E.,Mendel University in Brno | Merklova L.,Krajsky Urad Stredoceskeho Kraje
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2011

Vegetative phenological stages were evaluated in a spruce monoculture of the third age class in the region of the Drahanska vrchovina Upland. Methods of the ČHMU (Czech Hydro-Meteorological Office) were used. Temperature requirements of Norway spruce for the onset of particular phenological stages were evaluated on the basis of sums of air effective temperatures higher than 5 oC and at soil temperatures, values exceeding 1 oC were taken into account. In the paper, years 2005 to 2007 were evaluated. Results obtained were compared with long-term monitoring for the period 1991-2004. The onset and duration of phenological stages differed in particular years depending on the course of weather. Evaluation of the 17-year period shows that onsets of phenological stages in particular years differed markedly. An interval for the "onset of budbreak stage" was 13 days, at the "stage of 50% foliation" 14 days, the "stage of 100% foliation" 17 days. At the stage "full foliation", the interval amounts to 33 days in the period 1991 to 2007. The start of budbreak and foliation is affected by air and soil temperatures, which was also proved by statistical evaluations. High dependence between the onset of budbreak and air temperatures is confirmed by statistically significant correlation coefficients R2 = 0.854 (2005-2007) and R2 = 0.754 (1991-2004). Dependence of the onset of budbreak and foliation on the soil temperature is proved by a correlation coefficient R2 = 0.658 (2005 to 2007) and R2 = 0.687 in the period 1991 to 2004. Results show that in recent years, the earlier onset of spring phenological stages occurs at the higher sum of effective temperatures. The length of their duration shortens.


Bednarova E.,Mendel University in Brno | Merklova L.,Krajsky Urad Stredoceskeho Kraje | Truparova S.,Mendel University in Brno
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

The paper deals with results of phenological studies of Norway spruce (Picea abies /L./ Karst.) in a mixed stand. This broad range was important in spring phenological stages. High correlations were determined between the mean air temperature, soil temperature and the start of phenological stages. Relationships between the onset of phenological stages and changes in meteorological parameters were expressed by the sum of effective air temperatures exceeding 0 and 5°C To evaluate the relationships by means of the sum of effective temperatures >5°C, the stage of budbreak was most important. The onset of budbreak in Norway spruce occurred on average in the 125th day in the period 2005 to 2008. First, the stage of budbreak in spruce began the 121st day and at the latest the 128th day in 2005. The most often budbreak was in 2007. The onset of foliage in spruce began between the 128th day and the 136th day. Full 100% foliage occurred in 2007, viz. the 159th day, i.e. 12 day earlier than in the previous year. In 2005, full foliage occurred the 171st day. The air and soil temperatures affected spring phenological stages during the early spring, which was demonstrated by high correlation coefficients.


Bednarova E.,Mendel University in Brno | Truparova S.,Mendel University in Brno | Merklova L.,Krajsky Urad Stredoceskeho Kraje
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2012

The paper evaluates the onset and duration of spring vegetation phenological stages in a spruce monoculture of the third age class in relation to changing parameters of the environment in the region of the Drahanská vrchovina Upland. Temperature requirements of Norway spruce necessary for the onset particular phenological stages were evaluated on the basis of sums of effective temperatures > 5 °C. The period of 2005-2011 is processed in relation to long-term monitoring since 1991. Based on results obtained, there is considerable variability owing to changing climatic conditions in the onset of spring phenological stages in the course of monitored years. In recent years, the earlier onset of spring phenological stages occurs and their duration gets shorter. This phenomenon is caused by higher air temperatures in spring months. The statistical processing of results obtained demonstrated the high dependence of the onset of particular phenological stages on the temperature of air and soil.Particular factors affecting budbreak and foliation cannot be detached and thus, it is necessary to be evaluated as a complex of influences. Long-term phenological studies of forest trees can serve as the bioindicator of climatic changes.

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