# New Detection Method for Fungal Infection in Silver Fir Seeds
## 2 Silver Fir in the Bialowieza Forest  
There are only two known countries in Europe where silver fir grows naturally in low-lying areas: France (Normandy) and Poland (Yata, Topor, Mienia, Rudka, and Tisovik reserves) [19; 20; 21; 22]. Forests growing in the lowlands dominate in Poland at 84.8%, while the area of mountainous forests is 8.5% [23]. For almost 200 years, there has been a decline in wood resources and the area occupied by silver fir in European forests, known as the phenomenon of \"the decline of silver fir in its natural range\" [24]. According to some studies, the period of stagnation in some regions of Europe (Serbia) reaches 330 years [25]. It is assumed that this phenomenon was caused by a whole complex of biotic and abiotic factors, including the influence of humans [18; 22; 24]. However, the actual cause remains unclear to this day. Since 1981-1989, there has been a positive trend in the status of silver fir stands both in Poland and throughout Europe, which has improved significantly [24; 26]. In the Belarusian part of the Bialowieza Forest (which means wider forest) is the Tisovik tract (until 1939, called Cisowka), which is of interest because of two crucial circumstances: (1) this is the northernmost \"island\" of autochthonous silver fir growing in the lowlands (120 km from the nearest natural stand in the Jata Reserve) [27; 28; 29]; and (2) the only currently surviving relict population of _A. alba_ is present in the Tisovik tract, which is a part of the Bialowieza Forest, one of the largest forest areas in Central and Eastern Europe [30; 31]. For various reasons the silver fir population has never been large. From 1823 to World War II the number of silver fir trees fluctuated between 100 and 300 [32]. Currently only about 20 mature trees remain (unpublished data). In 1922, [PERSON] [33] found another very small group of silver fir trees in the Hubar tract, of the Bialowieieza Forest. According to the researcher, it was undoubtedly of natural origin. As we learned from the oral communication of colleagues from the National Park \"Belavezskaja Pusca\" (Belarus), this fragment has not survived. According to [PERSON] [34], who based, based his information on [PERSON] [33], the oldest silver fir tree, blown down by the wind in Tisovik in 1924, had a trunk circumference of 120 cm and a height of 33.5 m, corresponding to an age of at least 250 years. This means it became established in the second half of the 17 th century. This tree was a descendant of a silver fir which began to produce seeds at about 70 years of age [35]. Consequently, the beginning of the female parent's life of this 250-year-old tree was at the end of the 16 th to the beginning of the 17 th century. Thus, based on these estimates, the age of the silver fir population in Tisovik is over 400 years, but is likely much longer. As noted by [PERSON] [28], the appearance of silver fir in the Forest dates back to the climatic optimum of the Holocene. Such long preservation in the Forest of this unique stand, first described in 1829 by [PERSON] [27], and then studied in detail by [PERSON] [28], allows an assumption that particular genetic traits allowed for survival. However, it has often been suggested that this is a consequence of a favorable location, i.e., a small sandy island covered with forest on the watershed in the middle of impassable swamps and watercourses, which provided high air humidity and frequent indirect precipitation (dew, frost) [32], as well as a high level of groundwater. However, for more than half a century now, those swamps have undergone senescence and infill, and the level of the groundwater has dropped significantly. Tisovik, currently does not have favorable hydrological conditions for silver fir [36] and is at the extreme northern end of a range which allows silver fir to regenerate naturally [32]. This unique relict population may have highly suitable genetic properties [37] and is a promising source of seed and vegetative material.