INFLUENCE OF WEATHER CONDITIONS ON THE QUALITY OF SCOTS PINE (PINUS SYLVESTRIS L.) AND NORWAY SPRUCE (PICEA ABIES (L.) KARST.) SEEDS

One of the factors that could affect spruce and pine stands and consequently seed quality is a long-term climate change. The aim of the presented study is to evaluate the seed quality data of these tree species between the years 1973 and 2015 in relation to the temperature and precipitation in the territory of the Czech Republic during that period. The average absolute weight of Scots pine seeds during the reference period corresponded to the value provided in the Czech Standard CSN 48 1211 (2006); on the contrary, decrease in weight of Norway spruce seeds was apparent. No significant changes in germination energy and germination capacity have been observed over the years in regard to Scots pine. Germination energy has declined significantly in Norway spruce, and a stronger correlation has also emerged with germination capacity of full seeds. It turned out that the germination capacity of pine seeds is influenced by higher temperatures in the summer after blossom (June to August), while, in turn, the germination energy by the subsequent lower average temperatures in October to December. The correlation between total rainfall and seed quality was negative in February of the year preceding the harvest and in August of the year of harvest. Results in regard to Norway spruce showed a negative correlation between germination energy and average temperatures in March to August of the year of maturing. Correlation between precipitation and seed quality was not proved.