Growth of larch climatypes in the east siberia

Bobrinev V.P., Pak L.N.

Institute of Natural Resources, Ecology and Cryology, SB RAS, Russia pak_lar@bk.ru

Larch is the main forest-forming tree species in Russia, judging by its area and wood stock.

Its ability to grow in different climatic zones results in the broad species variability of genetically determined properties, inherited by the progeny via seed reproduction. The studies of larch variability and productivity related to the tree provenance is very important for increasing forest sustainability and productivity in the East Siberia.

The regular studies of climatypes of the main forest-forming tree species have begun in Russia since 1973 by the Order of the USSR State Forestry Agency dated February 6, 1973. The field experiment with different larch climatypes in the East Siberia (Chita Oblast, Russia) has been part of the program, having no analogues in the region.

The seeding and setting up of the plantations was carried out according to the program and instructions, authorized by the Council of Forest Genetics, Selection and Seed Production on April 5, 1972, and titled “The studies and establishment of new geographical cultures”. The larch climatype plantations were established by seeding in 1977 in the Chita Forestry (Ingodinsky forest seed subzone) and by now are represented by 4 species and 9 climatypes.

Mass seedlings of all larch samples appeared in the period of July 15-20. The larch samples of latitudally remoted origin (the Mountain Altai, Ivanovo and Sverdlovsk Oblasts) had longer periods of seedling. The 2-yo seedlings from the Chita Forestry had the best characteristics. The first estimation showed quite good survival of trees planted in 1980 (58.5-89.7%). The best survival rate was shown by the Siberian larch from the Krasnoyarsk Krai (90%) and the Mountain Altai (88%). Rather good survival rate was observed for the Chekanovsky larch from the Petrovsk-Transbaikalia Forestry of the Chita Oblast (73.5%), the Gmilin’s larch from the Chita forestry of the Chita Oblast (68.5%), the Siberian larch from the Kachug’s Forestry of the Irkutsk Oblast. Despite good survival of larch climatypes, the number of trees then decreased. Dying-off of larch trees had been observed every year at different rates. Analysis of climatypes height growth over 5 years showed that the Chekanovsky larch from the Petrovsk-Transbaikalia Forestry of the Chita Oblast was leading in this respect. At the age of 30 yo the best trunk diamether growth rate was shown by the Sukachev larch from the Sverdlovsk Oblast. Presently the best quality of tree stand is displayed by the Gmilin’s larch from the Chita forestry of the Chita Oblast and the Chekanovsky larch from the Petrovsk-Transbaikalia Forestry of the Chita Oblast.

The obtained results allow to conclude that different populations of the 4 larch species had become quite different in biological and ecological properties and economical peculiarities in the course of their long evolution. The fast-growing climatypes differed in growth rate since the moment of seedling. Worse growing conditions (temperature, moisture) in the region of planting as compared to the region of a climatype’s origin resulted in the decreased growth rate and sustainability of larch populations.