Seeds study, forest genetics and selection of the coniferous

Growth and variability of Korean Dahurian larch

(Larix olgensis A.Henry) in culture

Popkov B.V., Orekhova T.P.

Botanical Garden, FEB RAS, Vladivostok

Institute of Biology and Soil Science FEB RAS, Vladivostok, Russia

orekhova@ibss.dvo.ru

Much research has been focused on the genus Larix Mill., because larch is a very valuable and tolerant tree. Larch can be adapted not only for a wide range of environmental conditions and successfully survives pests, being capable to form "secondary" needles

Under favorable conditions larch can show intensive apical growth. The Korean Dahurian larch has a limited area and is included into the Russian Red book. The investigation of variability of this species is at the initial stage now (Milyutin, Koropachinsky, 2006; Semerikov, Poleshaeva, 2006). The Korean Dahurian larch has not been studied in culture.

The Korean Dahurian larch trees were planted on the territory of the Mountain-Taiga station of the FEB RAS on the area of 0.1 ha in spring 1999. The 1-year old seedlings (221 p.) from a natural population ("Pad' listvennaiy",Olgensky forestry farm of the Primorsky territory) were planted ( 2.1x 2.5 m).

The morphological parameters of seedlings (apical growth, stem diameter growth) were measured annually. The survival period in the Mountain-Taiga station was 2 years. The capacity of survival of the seedlings was 92 % during the seven years of observation.

The apical growth varied from 36.5 cm (min) to158 cm (max). The maximum growth of the leading shoot was observed only in 2005. The average height of seedlings was 6.6 ±0.1 m, ranging from 4.5 to 8.1 m. The average stem diameter (at 1.3 m height) was 6.1±0.3 cm, ranging from 3.4 to 10.1 cm. The leading shoot growth indicated 2 groups of trees: with shoot (105 ± 5 days) and slow (135 ± 5 days) periods of growth. The average apical growth in the first group was 81 ± 5 cm, and in the second group it was 108 ± 4 cm.

The studies of the phenotypic variability of the Korean Dahurian larch trees showed that the color of annual shoots varied from red-brown to yellow-green, while the colour of needles varied from dark-green to light-green. There were trees both with the spreading and dense and with the narrow and thin crowns. The morphological variations of the young bark of trees were found as well. The bark of a tree may be similar crack, plate and shell bark. The differences in the angles of attachment of branches to the tree stem were found to be either right or acute.

Our results concerning the growth and morphological variations of the Korean Dahurian larch confirmed that it is a prospective species for selection and forest restoration in future.