WOOD RESEARCH Volume 61, Number 3, 2016
Robert Kalbarczyk and Monika Ziemiańska

The effect of air temperature, precipitation and humidity on ring widths in the black locust (Robinia pseudoacacia L.) growing in urban conditions

This study characterizes the basic biometric traits of the black locust growing in urban conditions of the city of Wrocław (south-western Poland) and sets out the relationship between annual tree ring widths and air temperature, air humidity and precipitation. Materials consisted of 54 wooden discs taken from felled straight-trunked trees at four sampling sites at a height of 1.3 m from the ground in the area of a defunct garden established at the turn of the 20th century. Meteorological indicators were calculated based on daily data obtained from the Wroclaw meteorological station, part of the national atmospheric monitoring network. Tree ring widths were determined separately in heartwood and sapwood using LINTABTM 6 and TSAP-Win software, to an accuracy of 0.01 mm. Just over 85 % of the analyzed trees were at least 61 years old. In the heartwood layer the average tree ring width of 2.44 mm was about 1.08 mm wider than in the sapwood layer. Results confirmed the significant effect of warm winter and cool July on the ring widths of the black locust. The greatest demand for water was statistically proven in the period June to August in the year preceding the formation of the tree ring, and in the months January and September in the year of the tree ring formation.

WOOD RESEARCH Volume 63, Number 1, 2018
Monika Ziemiańska and Robert Kalbarczyk

Biometrics of tree-ring widths of (populus x canadensis moench) and their dependence on precipitation and air temperature in south-western poland

The aim of this study was to explore the structure of the basic biometric characteristics of Canadian poplar (Populus x canadensis Moench) growing on former farmland, and the influence of meteorological elements on the variability of tree-ring widths (TRW). The test was performed on stem discs. Measurements of TRW were made with the use of LINTABTM 6. The impact of meteorological conditions on the TRW of the examined poplars was determined using correlation analysis for the dependent variable – residual chronology and independent variables – rainfall and air temperature in the current year and the year preceding the formation of rings. The average TRW of the Canadian poplar was 6.70 mm, with a coefficient of variation of 45.6%. The average TRW in sapwood was 5.37 mm, 2.11 mm less than in heartwood. The site chronology represented the period 1967-2014 (48 years). Our study demonstrated a significant correlation between rainfall and temperature on TRW in Populus x canadensis. The greatest demand for water by the Canadian poplar was observed in April and September of the current year. In contrast, the effect of air temperature most negatively affected TRW in June-July of the previous year (especially July) and April-May of the current year. In the designated chronology we established 13 pointer years, 7 positive and 6 negative. Negative years were determined in the years in which the shortage of rainfall was up to 50% of the norm, and positive indicator years where precipitation was higher than in the multi-annual period, even >150%. Both the correlation analysis and the analysis of indicator years indicated rainfall as a factor determining the size of the tree-ring width in Canadian poplars. In recent years, Poland has seen a resurging interest in planting poplars, following a long-term global trend in forestry and the paper industry which requires fast-growing tree plantations. The authors of this study attempted to address the gap in knowledge about the impact of meteorological elements on the tree-ring widths of Populus x canadensis in the conditions of south-west Poland.