Considering specific role of forest in carbon cycling, the scope of the study is evaluation of assimilation of carbon dioxide in a single grey alder stand. The National statistical forest inventory demonstrates that total area of afforested farmlands is 314 thousands of ha, including 212 thousands of ha are grey alder stands. Empiric data are collected in 2011 in 15 years old grey alder stand representing Aegopodiosa site type, site index II. Dendrometric characteristic of the stand are estimated using a method of 6 sample tree plots. Average height of dominant trees is 9.6 ± 0.14 m, diameter at breast height - 6.7 ± 0.18 cm, volume of stem - 0.02002 ± 0.00673 m3, number of trees per ha – 5806 ± 560, growing stock - 116.2 ± 20.0 m3 haE-1. Density of the grey alder stem wood is 411.0 ± 2.2 kg mE-3, average relative moisture - 51.6 ± 0.13%. Dry biomass of grey alder in the evaluated stand is 73.4 tons haE-1, including stem biomass - 65.3%, branches - 11.1%, leaves - 2.3%, stump - 6.8% and roots - 14.6%. In average evaluated stands accumulated 36.9 tons haE-1 of carbon removing from atmosphere 135.5 t ha-1 of CO2. Wood density is estimated according to ISO 3131:1975 standard, moisture content – according to EN13183-1:2002 standard.

Plant factories provide possibilities to get optimal yield of green leafy vegetables entire year independent from the season. The technology of light-emitting diode (LEDs) light has become one of the most powerful tools in photophysiological researches of various horticultural plants. In order to manage plant physiology and improve productivity, it is necessary to develop new LEDs technologies in horticulture. The aim of the study was to investigate different lighting intensities and elevated red light (660 nm) effect on tatsoi photosynthetic parameters. All plants were grown under the same light sources where overall photosynthetic photon flux density (PPFD) varied from 200 to 300 µmol mE-2 sE-1. Three days before harvesting red light intensity (640 and 660 nm) was increased until 132 µmol mE-2 sE-1 and 660 nm until 188 µmol mE-2 sE-1 at 16 hours photoperiod. In the last treatment merely 24 hours photoperiod was applied. The photosynthetic indices in tatsoi were determined by non-destructive methods using LI-6400XT portable photosynthesis system, OS5p fluorometer, DUALEX optical sensor and CID leaf spectrometer. Research was performed in 2017 – 2018 winter season. The obtained data revealed that the total photosynthetic photon flux density (PPFD) at level of 200 µmol mE-2 sE-1 was sufficient for optimal CO2 assimilation in tatsoi plants. The increased PPFD of LED light at pre-harvest stage resulted in reduced photosynthetic parameters of plants.

The effects of different climatic conditions on birch (Betula pendula Roth) and poplar (Populus) hybrids seedlings were studied. This study consists of two parts, firstly, an experiment with poplars and, secondly, the experiment with birch seedlings. The aim of this study was to evaluate the growth of birch and poplar seedlings under the current and modelled climatic conditions. Results showed that the simulation of short-term warmer weather conditions and higher CO2 concentration led to more intensive growth of silver birch saplings. Different climatic conditions did not significantly change photosynthetic and transpiration rate of one year old silver birch seedlings. Contrary the transpiration and photosynthesis rate of poplar seedlings significantly depended on drought and clone but not on hybrid. Drought altered the transpiration and photosynthesis intensity, water use efficiency, and correlation among most of the traits. The P. maximowiczii × P. trichocarpa, P. balsamifera × P. trichocarpa hybrids increased their water use efficiency under the drought conditions and were characterized by faster growth hybrids. The sensitivity of poplar hybrids to UV-B radiation varied and depended on the origin of their parental trees: poplar hybrids from the northern latitudes were more sensitive to the increased UV-B radiation than those of southern origin. The best growth after simulated warm winter was obtained for the P. deltoides × P. nigra and P. nigra × P. nigra hybrids, originating from the southern areas. The findings from this experiment are more applicable to young birch and poplar trees, but stress on young trees may be reflected in future tree growth.

Light is one of the most significant environmental factors affecting the growth of plants, as it is the driving force of photosynthesis. Among others, the red and blue light are the most relevant, as these spectral regions are absorbed by chlorophyll the most. In addition, red and blue light trigger specific photomorphogenic responses that allow plants to capture the available light efficiently. Accordingly, the proportion of red and blue light (R:B ratio) is considered one of the most important characteristics of light for plants, as optimal R:B provides balanced growth and photosynthesis. The aim of this study was to evaluate how the in vitro cultures of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) are affected by different R:B ratios under fixed illumination intensity. We examined the growth characteristics of plantlets under wide spectrum LED luminaires with three different R:B proportions – 1:1, 7:3 and 9:1. While photosynthesis-related variables were significantly affected by light, the effect on morphology was less pronounced. Overall, increased proportions of red light decreased the photosynthetic performance of plantlets without giving significant benefits in the form of longer shoots that could be used to facilitate propagation effectiveness. Nonetheless, the effect of light treatment remains at least partially clones-specific and should be considered in case of further application for propagation purposes.