Local chronologies of Sawara cypress
Five stands of Sawara cypress [Chamaecyparis pisifera (Siebold & Zucc.) Endl.], from northwestern and central Poland were selected for study:
1. Arboretum Glinna (GL), ϕ 53°17'N, λ 14°43'E, 68 m a.s.l., 12 sampled trees;
2. Drawsko Pomorskie (DR), ϕ 53°52'N, λ 15°82'E, 115 m a.s.l., 21 sampled trees;
3. Sieraków (SI), ϕ 52°65'N, λ 16°09'E, 48 m a.s.l., 23 sampled trees;
4. Arboretum Wirty (WI), ϕ 53°89'N, λ 18°37'E, 131 m a.s.l., 21 sampled trees;
5. Arboretum Rogów (RO), ϕ 51°49'N, λ 19°53'E, 194 m a.s.l.), 20 sampled trees.
Samples were taken from 97 trees (dendrochronological analysis was based on a total of 167 cores, which yielded over 11300 measured tree-rings), using Pressler borers at breast-height. Tree-ring widths were measured down to 0.01 mm. Tree-ring width in the studied populations of Sawara cypress varies (from 1.94 to 4.47 mm). The oldest Sawara cypresses grow in Glinna Arboretum and are nearly 130 years old. The youngest ones grow in Rogów Arboretum (67 years old) and Wirty Arboretum (58 years old).
The longest chronology was obtained for the GL plot. It spans 122 years (1899-2020), for EPS>0.85: 75 years (1946-2020), and the shortest chronology – spanning only 58 years – was compiled for the WI plot (1961-2018), for EPS>0.85: 50 years (1969-2018). Chronology DR spans 1116 years (1905-2020), for EPS>0.85: 89 years (1932-2020), chronology SI spanning 82 years (1939-2020), for EPS>0.85: 75 years (1946-2020) and chronology RO spans 67 years (1953-2019), for EPS>0.85: 58 years (1962-2019).
