Flame Heat Sources as a Sustainable Method of Protecting Fruit Orchards against Frost in Poland

One of the key factors affecting the yield of fruit orchards is their protection against spring frosts. This paper presents the methods currently used (like anti-frost nets, chemical agents, etc.) and proposes an alternative method of raising the temperature around fruit trees using flame heat sources with a suitable heating power. Flame heat sources in the form of metal containers filled with paraffin were utilised in this experiment. The effect of the flame heat sources on the relative increase in the temperature of a wooden surface (simulating trees located in Rzeszow, Poland) depending on the distance from the heat source was measured and estimated based on mathematical models. Based on the results of experimental work, an optimal placement of flame heat sources (1.58 m from each tree) was proposed for orchards of semi-dwarf fruit trees. The proposed modifications of the flame heat sources to incorporate infrared radiation converters resulted in a greater increase in the temperature of the wooden surface. The analysis of the available economic and environmental data showed that the proposed method may be a competitive alternative to the standard method of protection. If the flame heat sources are filled with combustible materials derived from renewable sources, such as those produced from fats, the overall CO 2 emission balance for this solution will be significantly more favourable. The use of flame heat sources does not necessitate the introduction of permanent changes in the environment, as is required in cases when irrigation infrastructure is installed.