Phenological development of fagus sylvatica L. and Aesculus hipocastanum L. in relation to mean monthly temperatures for the Kočevje locality during 1961-1990

Long-term phenological development of forest trees and shrubs is an important indicator of changes in the onset of specific phenological phase at different sites in relation to meteorological conditions. Correlation analysis and linear multiple regression were used to establish relationship between phenological phases for Fagus sylvatica and Aesculus hippocastanum and mean monthly air temperatures for the Kočevje locality in the period 1961-1990. Correlation coefficients between the onset of phenological phases with air temperature of the previous 2-3 months were relatively high. For Fagus sylvatica, the highest variability was explained with phenological model for the beginning of leaf colouring (58 %) with first independent variable mean monthly temperature for the months of February, April and May and as second independent variable mean monthly temperature for the months of July, August and September. For Aesculus hippocastanum, the highest variability was explained with phenological model for the beginning of flowering (65 %) with first independent variable mean monthly temperature for the months of April and May and as second independent variable mean monthly temperature for the months of January, February and March. In general, the beginning of leaf colouring in Fagus sylvatica is a good indicator of temperature characteristics of the site

Phenological development of fagus sylvatica L. and Aesculus hipocastanum L. in relation to mean monthly temperatures for the Kočevje locality during 1961-1990

Analiza nastopa fenoloških faz gozdnega drevja in grmovja v dolgem časovnem nizu nam pojasnjuje odvisnost med časom pojavljanja določene fenofaze ter meteorološkimi razmerami. Na lokaciji Kočevje smo ugotavljali korelacijo med nastopom fenofaz za bukev (Fagus sylvatica L.) ter navadni divji kostanj (Aesculus hippocastanum L.) ter povprečnimi eno-, dvo- in tromesečnimi temperaturami zraka za obdobje od leta 1961 do 1990. Korelacije so tesnejše, če uporabimo povprečja temperatur dveh ali treh zaporednih mesecev. Največji delež pojasnjene variabilnosti pri bukvi smo dosegli z modelom za napoved začetka rumenenja listja (58 %). Kot prva pojasnjevalna spremenljivka se pojavlja povprečna temperatura v mesecih februarju, marcu in aprilu, kot drugapa povprečna temperatura mesecev julija, avgusta in septembra. Pri navadnem divjem kostanju smo največji delež pojasnjene variabilnosti dosegli zmodelom za napoved začetka splošnega cvetenja (65 %), na katero najbolj vplivajo povprečne temperature mesecev aprila in maja ter mesecev januarja, februarja in marca. Na splošno je začetek rumenenja listja pri bukvi dober kazalec temperaturnih razmer rastišča.Long-term phenological development of forest trees and shrubs is an important indicator of changes in the onset of specific phenological phase at different sites in relation to meteorological conditions. Correlation analysis and linear multiple regression were used to establish relationship between phenological phases for Fagus sylvatica and Aesculus hippocastanum and mean monthly air temperatures for the Kočevje locality in the period 1961-1990. Correlation coefficients between the onset of phenological phases with air temperature of the previous 2-3 months were relatively high. For Fagus sylvatica, the highest variability was explained with phenological model for the beginning of leaf colouring (58 %) with first independent variable mean monthly temperature for the months of February, April and May and as second independent variable mean monthly temperature for the months of July, August and September. For Aesculus hippocastanum, the highest variability was explained with phenological model for the beginning of flowering (65 %) with first independent variable mean monthly temperature for the months of April and May and as second independent variable mean monthly temperature for the months of January, February and March. In general, the beginning of leaf colouring in Fagus sylvatica is a good indicator of temperature characteristics of the site

Heat waves analysis and the heat load of agricultural workers during the heat waves in 2017 (using index WBGT)

Workers in agriculture are regularly exposed to heat stress during summer, which can affect reduced labour productivity and income losses. Air temperatures in Slovenia have been rising in recent decades, and climate change projections show that this trend will continue along with an increase in the number of days with heat stress risk. Changes in the number of heat waves in central and south-western Slovenia for the period 1961–2017 were analysed as well as the risk of the heat stress for workers during heat waves in the year 2017. The heat wave occurs if the temperature threshold for the average daily temperature is reached or exceeded on at least three consecutive days, with the threshold for the mild continental climate (Ljubljana) 24 °C and the mild Submediterranean climate (Bilje) 25 °C. The WBGT (Wet Bulb Globe Temperature) index, assessing the risk of heat stress, was calculated from relative humidity and air temperatures. At both locations, the number of days in heat waves increased as well as their intensity, average daily air temperatures were significantly higher than in the first half of the considered period. The time span, in which the heat waves occur, also extended, as until 1990 they did not appear in early June and late August, as in recent years. The calculated values of the WBGT show that for most days in the heat waves in 2017 in Ljubljana and Bilje, the WBGT 23 °C threshold was exceeded practically all day, which shows a high level of heat stress risk for physically intense work. In the case of exceeded WBGT reference values, employers or farmers themselves should take actions to reduce the risk of heat stress

The effect of hot days on occupational heat stress in the manufacturing industry: implications for workers' well-being and productivity

Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981–2010. Observed trends (1961–2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.The work was supported by the European Union Horizon 2020 Research and Innovation Action (Project number 668786: HEATSHIELD)