Monitoring the damage to epicuticular waxes at silver birch (Betula pendula Roth.) in the changing air pollution spectrum of the Ore Mountains

The paper deals with the study of damage to the assimilatory apparatus of silver birch (Betula pendula Roth) using the study of changes of epicuticular waxes in the period 1997 to 2009. During the period, changes in the air pollution spectrum occurred in the area of the Ore Mountains. At the beginning of the monitoring, above-limit concentrations of sulphur oxides were the main anthropogenic factor. These concentrations resulted in the degradation of epicuticular waxes. Statistical evaluations demonstrated the high dependence of damage to epicuticular waxes on high concentrations of sulphur oxides. Damage to epicuticular waxes by air pollution increased with the increasing altitude of a forest stand. Since 2001, measured values of SO2 decreased to a minimum but a new phenomenon appeared damaging the assimilatory apparatus of forest stands, namely above-limit concentrations of ground ozone. These above-limit concentrations of ground ozone damage the assimilatory apparatus including epicuticular waxes at all silver birch stands occurring at altitudes above 800 m. This finding was also proved by the high coefficient of determination

Evaluation of vegetative phenological stages in a spruce monoculture depending on parameters of the environment

Vegetative phenological stages were evaluated in a spruce monoculture of the third age class in the region of the Drahanská vrchovina Upland. Methods of the ČHMÚ (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

Měření koncentrací přízemního ozonu pasivními dozimetry pro potřeby monitoringu zdravotního stavu lesů

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Results of a phenological study at a young Norway spruce (Picea abies/L./Karst)

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

Monitoring the spring phenological stages in a spruce monoculture in the Drahanská vrchovina upland in 2005–2011

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 oC. 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

The onset and duration of vegetative phenological stages in European beech (Fagus sylvatica L.) under changing conditions of the environment

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

Results of a phenological study of the European larch (Larix decidua Mill.) growing in a mixed stand

This paper presents an evaluation of the onset and duration of phenological stages of the European larch (Larix decidua Mill.) growing in a mixed stand in Drahanská vrchovina highlands. It covers the period of 2007–2010 and refers to results obtained in the preceding study period of 1991–2006. In individual years of this study, beginnings and durations of individual phenological stages differed in dependence on climatic conditions. Temperature requirements of European larch regarding the onset of individual phenological stages were evaluated on the base of sums of air temperatures above 0° C and of effective air temperatures higher than +5° C. Obtained results indicate that the onset and duration of spring phenological stages are dependent on air and soil temperatures already in the early spring. As far as the European larch is concerned, the breaking of buds is dependent on temperatures of air and soil; the corresponding correlation coefficients were R2 = 0. 8684 (y = −3.788x + 97.165) and R2 = 0.7627 (y = −6.667x + 101.88), respectively. The obtained results indicate that recently the onset of spring phenological stages occurred earlier and earlier in the study area of Drahanská vrchovina highlands and that their course was also shorter and shorter. In spring months, higher temperatures influence the phenological stage of flushing at most while in the autumn individual phenological stages occur later and later so that the growing season is longer and longer. This finding was corroborated by results of long-term studies

How timing of stem girdling affects needle xylem structure in Scots pine

While needles represent a proportionally large fraction of whole-plant hydraulic resistance, no studies to date have investigated how source–sink disturbances affect needle xylem structure. In this study, we evaluated structural changes in xylem in current-year needles of Scots pine 227 and 411 days after stem girdling (hereafter referred to as DAG). Maximum and minimum tracheid lumen diameters and therefore also the size of tracheid lumen areas increased in needles 227 DAG compared to control needles. In contrast, tracheid dimensions were similar in needles 411 DAG as in the control needles, but smaller xylem area and lower number of tracheids resulted in the lower theoretical needle hydraulic conductivity of those needles. Several needle xylem parameters were intercorrelated in both control and girdled trees. These observed changes provide a new understanding of the processes that occur following a source–sink disturbance. Considering anatomical parameters such as the number of tracheids, tracheid dimension, or needle xylem area, which are rarely described in physiological studies, could be helpful, for example, in understanding to tree hydraulic systems or for modeling gas exchange. Finally, empirical equations were developed to calculate needle theoretical hydraulic conductivity and the number of tracheids in needles using an easily measurable parameter of needle xylem area