The Impact of Climate Change in Phenophases of Forestry Species in Urban Areas

Phenology is the study of the temporal occurrence of biological events that repeat each year, the occurrence of which depends on biotic and abiotic factors [1,2]. Plant Phenology is the scientific study of biological stages, such as flowering, leaf unfolding, seed set, and senescence in relation to climatic conditions [3]. Environmental factors such as temperature and humidity can affect phenological stages [4,5]. Climate change affects bioclimatic conditions during the growing period of trees [6,7]. Temperature is the major abiotic factor that affects the phenological stages of the trees [8]. Global warming is disrupting the phenological phases [8,9]. The time of leaf development, the time of the beginning of flowering, the time of development of fruit, the time of leaf fall are the main phenological stages [3]. The recording of the start date of phenological stages and relating them to temperature has an important role in plant phenology study [10]. The sensitivity of phenology to temperature changes makes it an indicator of vegetation response to environmental changes and can be used to monitor the effects of climate change globally [11,12]. As phenology is an indicator to detect climate variability and climate change the monitoring of phenophases of species is important to extract results for climate change.

The Phenological Monitoring Area was created in School of Forestry on December 2020, within the framework of the project LIFE CliVut (Climate Value of Urban Trees) LIFE18 GIC/IT/001217. It contains 100 individuals (5 per species), 10 species of trees and 10 species of shrubs. The forest species are presented in Table 1.

Trees were planted at a distance of 5m from each other and shrubs were planted at a distance of 4m. The phenological stages of the plants were studied from March to December 2021 and throughout 2022 till now. For each individual, leaf development, flower development, development of fruit and leaf fall were recorded on a weekly basis taking into consideration BBCH scale. BBCH scale as a standard system for describing the phenological stages of plant development has been introduced by The Global Phenological Monitoring Network [13]. Zadoks et al. (1974) developed the decimal code, which is divided into principal and secondary growth stages [14]. (Table 2)

The results of the two-year monitoring in PMA of School of Forestry are presented below. (Tables 3 & 4)

According to the above data the differences between two years are presented below:
Acer campestre, Alnus glutinosa and Quercus ilex developed their leaves earlier in 2021.
Prunus avium, Fraxinus angustifolia, Carpinus betulus, Sorbus domestica and Populus canescnes developed their leaves earlier in 2022 than 2021.
Tilia cordata, Quercus pubescens did have not a big difference in leaf development between two years.
Punica granatum, Spartium junceum, Cornus sanguinea, Salix caprea, Berberis vulgaris, Phyllirea latifolia, Sambucus nigra developed their leaves earlier in 2022 than 2021.
Ligustrum vulgare, Euonymus europaeus did have not a big difference in leaf development between two years.
Corylus avellana developed its leaves later than 2021.

None.

The authors declare no conflict of interest.

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