The age and genetics of individual larches in four rural parks and at the Järvselja Educational and Experimental Forest Centre in Estonia

Abstract The article investigates the historical presence and current status of larch trees within the parks of five former manors in South Estonia: Kastre and its Peravalla forest district (now Järvselja Educational and Experimental Forest Centre), Mäksa, Kabina and Mõniste. Before 1918, South Estonia was part of the province of Livonia in the Russian Empire. The analysis encompasses taxonomy, habitats and the introduction of various larch species. Selected larch trees within these parks were dated using dendrochronological methods. The research revealed a consistent pattern of larch tree planting over a century, occurring in seven distinct rounds between the 1820s (Kastre Park) and the 1940s (Järvselja) as follows: 1) 1820 and 1895 (Kastre), 2) 1907 and 1920–1940 (Järvselja), 3) 1825–1840 (Mõniste), 4) 1855–1865 (Kabina), and 5) 1870–1880 (Mäksa). Genetic characterization was applied to determine individual tree species based on morphometric determinations. The majority of larch trees within the parks were genetically confirmed as European larches, which was consistent to the morphological assessments conducted at Kastre, Järvselja and Mäksa. The analysis revealed that a younger, naturally propagated larch located at Kastre with morphological characteristics of European larch showed subtle genetic indicators of Japanese larch. The cause of this unexpected finding remains vague. It is hypothesized that this specific tree might represent a hybrid of European and Siberian larches, given its inclusion within a stand hosting both species in proximity. At Järvselja, the genetic method confirmed the morphological identification of four larches as Japanese and two as Dunkeld larches. Six Siberian larches (sensu lato) located at Kastre and Järvselja were genetically identified as hybrids of Japanese and European larches while the cause of this hybridization remains unclear. Utilization of genetic markers not validated for Russian ( L. archangelica ), Siberian ( L. sibirica s. str. ), and hybrid ( L. decidua × L. sibirica and L. sibirica × L. decidua ) larches makes the obtained results inconclusive. In the case of Mäksa, both morphological and genetic analyses confirmed the presence of Japanese and Euro-Japanese larches, which was previously confirmed. It is important to note that the classification of L. leptolepis × L. decidua proposed by Bobrov is considered incorrect. Trees displaying similar characteristics, especially older specimens, should be classified according to Bobrov’s description as L. decidua f. kaempferi or f. marschlinsii .