The experience of larch growing in Ukraine as introduced crop shows positive results. The essential influence of geographical origin of the seeds on productivity, quality, and resistance of the created plantations was found.
The aim of our study was to analyze 60-year dynamics of growth and development of larch provenances in provenance trial plantations in Left-bank Forest-Steppe of Ukraine and determination of the promising species and provenances to bring under cultivation in forest plantations.
Materials and Methods
The objects of research were the larches provenance trial plantations in the State Enterprise “Trostyanets Forest Economy” of Sumy region, created by 2-year-old seedlings on an area of 1.73 hectares in fresh fertile forest site type in 1954. From the 24 variants of the seeds which were received from different geographical locations of the former USSR and represented almost the entire natural range of the species, 15 variants had been planted: 5 larch species and their ecotypes: Larix decidua L.(1) L. Sukaczewii Djil. (6), L. sibirica Ldb. (3), L. ? Czekanowskii Sz. (2) and L. dahurica Turcz. (3). As a control, seedlings of L. Sukachevii Djil. of the third generation from the State Enterprise “Trostyanets Forest Economy” were used from.
The dynamics of inventory parameters of 15 provenances of genus Larix over a 60-year period was studied. The surveys were done in 1971, 1978, 1983, 1993, 2003 and 2013. The patterns of age dynamics were revealed. The larches provenances which had high growth intensity at a young age retained leadership up to 60 years. The following larch provenances which had been the best in 7 years old confirmed their high inventory parameters at the age of 60 years: L. decidua L. from Transcarpathia (diameter 4.8–36.1 cm; height 4.2–28.7 m), L. ? Czekanowskii Sz. from Irkutsk region (diameter 5.9–39.5 cm; height 4.5–29.7 m), L. dahurica Turcz. from Khabarovsk region (diameter 4.5–33.2 cm; height 4.3–28.8 m) and L. Sukachevii Djil. from Perm region (diameter 3.3–34.3 cm; height 3.9–25.0 m). Offspring of L. sibirica Ldb. from Khakassia region (diameter 3.2–25.5 cm; height 4.2–25.0 m) and L. dahurica Turcz. from Buryatia region (diameter 2.9–28.0 cm; height 3.6–25.6 m) had persistently low inventory parameters (excluding died out variants). The remaining variants for the entire observation period have been grown at the control level (diameter 4.3–29.0 cm; height 4.6–28.7 m). By average trunk volume, L. x Czekanowskii Sz. from Irkutsk region (1.66 m3) and L. decidua L. from Transcarpathia (1,3 m3) provenances significantly exceeded the control variant and more than 2 times, the least productive variant of L. sibirica Ldb. from Khakassia region (0.6 m3). The average trunk volume of the other variants was as of the control.
The positive relationships between the diameters were revealed throughout the whole observation period. Thus, the correlation between the diameters at 60 and 7 years is moderate (r = 0.56), in subsequent years the correlation is strong (r = 0.88, 0.92, 0.88, 0.92, and 0.87, respectively, for 60 and 18, 25, 40, and 50 years). This indicates a high probability that individuals which had high diameter values at a young age to be leaders in the future as well, while those that had low values would not become better. The height correlation is positive too, but its indexes are some lower. Only a trend have been observed (r = 0.22) between the height at 7 and 60 years, but later on, there were strong and moderate correlations between the height in 60 and 18, 25, 30, 40, and 50 years (r = 0.78, 0.63, 0.74, 0.66, and 0.65, respectively). Strong positive relationships have been observed between the average trunk volumes of provenances throughout the whole observation period (r = 0.92–0.95).
- Retaining leadership was revealed for individual provenances for the 60-year period, that providing the possibility of early diagnosis of provenances with high adaptive capacity and productivity by diameter and average trunk volume from 10 years and by height from 15–20 years.
- In Left-bank Forest-Steppe of Ukraine, the following larches are perspective by growth intensity: L. ? Czekanowskii Sz. (Irkutsk proveniences, the zone of introgressive hybridization of L. sibirica Ldb. and L. dahurica Turcz.), L. decidua L. (Transcarpathian proveniences), L. Sukachevii Djil. (Yekaterinburg region.), and L. dahurica Turcz. (Khabarovsk region).
- The progenies of L. Sukachevii Djil. from Komi Republic, Yekaterinburg and Perm regions, L. dahurica Turcz. from the Chita region and mountain proveniences of L. sibirica Ldb. from Altai appeared to be nonresistant in Left-bank Forest-Steppe fresh fertile site conditions.