Wyniki wyszukiwania - BazTech

1

Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus petraea) in the Czech Republic

Rybníček M., Čermák P., Žid T., Kolář T., Trnka M., Büntgen U.

Geochronometria

|

2015

|

Vol. 42, no.1

17--27

EN

Unraveling climatic effects on growth of oak — Europe’s most ecologically and economically important forest species — has been the subject of many recent studies; however, more insight based on field data is necessary to better understand the relationship between climate and tree growth and to adapt forest management strategies to future climate change. In this report, we explore the influence of temperature, precipitation and drought variability on the productivity and vitality of oak stands in the Czech Highlands. We collected 180 cores from mature oaks (Quercus petraea) at four forest stands in the Czech Drahany Highlands. Standard dendro-methods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Crown vitality was also evaluated, using the modified ICP Forests methodology. Late spring precipitation totals between May and June as well as the mean July temperature for the year of ring formation were found to be the most important factors for oak growth, whereas crown condition was significantly affected by spring and summer drought. This study is representative for similar bio-ecological habitats across Central Europe and can serve as a dendroclimatological blueprint for earlier periods for which detailed meteorological information is missing.

2

Growth responses of Norway spruce (picea abies (l.) karst.) to the climate in the south-eastern part of the Českomoravská Upland (Czech Republic)

Rybníček M., Čermák P., Kolář T., Žid T.

Geochronometria

|

2012

|

Vol. 39, no. 2

149-157

EN

The research was conducted in selected 80- to 110-year-old spruce stands in the south-eastern part of the Českomoravská Upland at altitudes from 350 m a.s.l. to 465 m a.s.l. The regional standard tree-ring chronology shows very low increments for years 1974, 1976 and 1992. After 1992, there is a sharp rise in increments with a climax in 1997. Afterwards, increments gradually decrease, reaching minima in 2003 and 2008. The years with low increments were also confirmed by the analysis of negative pointer years when over 80% of the analysed trees responded by a sharp decrease in increment, mainly in years 1976 and 1992. We can usually find values of monthly precipitation or monthly temperature average which can explain or help explain these falls in the radial growth. The correlations of diameter increments with average monthly precipitation gain only positive statistically significant values, namely for the months of May, June, July and August of the particular year. The correlations of diameter increments with average monthly temperatures gain only negative statistical-ly significant values, namely for the months of June, July and September of the previous year and January and August of the particular year. In the examined area there is a significant negative correlation between average temperatures and monthly precipitation in July, August and September. The results of the habitual diagnostics show that with respect to the climatic conditions the health condition of the monitored stands is relatively good. On average, the defoliation does not exceed the values as-certained in different territories of the Czech Republic.

3

Adial growth and health condition of norway spruce (Picea abies (L.) Karst.) Stands in relation to climate (Silesian Beskids, Czech Republic)

Rybníček M., Čermák P., Žid T., Kolář T.

Geochronometria

|

2010

|

Vol. 36

9-16

EN

The research was conducted in selected spruce stands of the Silesian Beskids aged over 70 at altitudes from 403 m a.s.l. to 794 m a.s.l. in 2008. The samples were taken and processed in compliance with standard dendrochronological methodology. Tree rings were measured and the treering curves were synchronized using the PAST4 application. The age trend was removed in the ARSTAN application and the climatic influences were modelled in the DendroClim application. The regional standard tree-ring chronology shows an obvious decrease in the radial increment from the beginning of the 1970s to the mid-1990s. The gradual increase in radial increment which followed in the second half of the 1990s was interrupted in 2000, 2003, and 2006. Most of the years with the decreased radial increment have been confirmed by the analysis of significant negative years. The radial increment statistically significantly correlates with the precipitation in July and September of the previous year, precipitation in June of the year in question and precipitation during the vegetation period. Moreover, the growth of spruce is statistically significantly affected by temperatures in October of the previous year and March of the year in question. Additionally, the paper includes habitual monitoring of trees and the volume of salvage cutting in these districts. The condition of the habit of trees and the development of salvage cuttings agree with the hypothesis about strong stress load or its considerable increase in 2003 and the following years.