# Peat Thickness Changes at the \"Wolosate\" Raised Bog in the Western Bieszczady Mountains
## 2 Materials and Methods
The study demonstrated that the annual increments in the acrotelm layer on the \"Wolosate\" bog were the lowest (3.16-3.90 mm per annum) compared to the Bieszczady Mountain peatlands located in the San River valley (3.99-5.55 mm per annum). A floristic study [43] demonstrated that almost the entire area of the peatland is covered with sphagnous swamp (_Sphagnum magellanici_), while in the central part of the dome, there occurs a patch of continental marsh species (_Ledo-Sphagnum magellanici_). A palynological study on the \"Wolosate\" bog was also conducted by [PERSON] [44,45]. In the process of peat formation, the occurrence of a short phase of marsh spruce and wet leafy forest with _Almus glutinosa_, followed by the formation of a raised bog, can be observed. All studies into the rate of peat subsidence on the,,Wolosate\" bog applied the most up-to-date, precise survey technique. In 1967, the classical angular and linear measurement method was employed. At the same time, the basic, characteristic levelling and stratigraphic cross-section was established [31]. Along the longitudinal cross-section, 12 control points were set out at fixed distances of 20 m, using a precise theodolite and measuring tapes. The last 13 th point was set at a distance of 25 m from the point no. 12. Thus, the total length of the tested cross-section was 245 m. Later, the points underwent permanent anchoringin the mineral substrate with appropriate rods. The rods were installed in previously drilled holes, pre-prepared with an \"Instore core\", and then widened with an Edelman soil auger with a diameter \(\phi\) of 10 cm. Values for grand level in the set-out control points were determined based on direct levelling surveys by the geometric technical levelling method with increased accuracy. Referring and controlling the surveys took place in relation to the temporary benchmark located at the abutment of a permanent, reinforced concrete culvert under the regional road No. 897, and directly adjacent to the object under study. In this way, the sub-millimetre accuracy (4-5 mm) of the determined measuring point elevations was obtained. Subsequent surveys in the years 1980 and 1988 were also carried out by classical land surveying methods. To determine the elevations of the control points (No. 1-13), researchers used geometric levelling method on the examined cross-section in these periods; this lead to obtaining an accuracy of 3-5 mm. The last survey was carried out in 2016 using a modern GNSS (Global Navigation Satellite Systems) satellite technique by the method of kinematic measurements in real time. To this end, a multi-functional active geodetic network established in Poland in the form of ASG-EUPOS system was used. The network is, at the same time, part of the European continental EPN (EUREF Permanent GNSS Network) network and the global ICS (International GNSS Service) network. This approach has offered access to the European Terrestrial Reference System 1989 (ETRS89) which is a standard precise GNSS coordinate system for the whole of Europe. At the same time, ETRS89 provides the basis for geolocation data throughout Europe, both at the national and international level. The measurements on \"Wolosate\" raised bog used a multi-system GNSS (GPS + GLONASS + Galileo + BeiDou) receiver, and Trimble R10 satellite set with TSC3 controller. This set, using a support system in the form of terrestrial satellite network ASG-EUPOS, ensured an accuracy of 1 cm in the 3D coordinated determination on the studied object, in the global spatial reference system WGS84 (Word Geodetic System 84). Then, the obtained survey results (WGS84) were transformed to the systems currently valid in Poland i.e., flat coordinate system PL-ETRF2000 and normal height system PL-KRON86. In this case, elevations of the control points (no. 1-13) on the tested cross-section were determined using the satellite leveling method with an accuracy of 5-6 mm.