by Dr. Yevgeny TITOV, Voronezh State Forest Technology Academy
We all know about botanical gardens which are planted and maintained by specialists for scientific and aesthetic considerations. Their fruit-trees and brushes yield wonderful fruits, nuts and berries. But only experts are familiar with the remarkable forest-gardens of Siberia. They are not only unique in their structure, but can become the main source of these rare and most valuable nutritious cedar nuts, to say nothing of the air in their grounds filled with unique and health-giving resinous aroma.
Only few of the pine varieties on this planet yield edible seeds. They are located in the subtropical belt of the Rocky Mountains in the United States, in Afghanistan, Himalayas, China and in the Mediterranean region. The largest territory on this planet (36 mn hectares) is occupied by what experts call the Swiss Stone Pine of Siberia (sibirica) or cedar-resident of the boreal zone of Russia. For centuries its nuts have been hailed as delicacy and a remedy from ailments in different countries, including Europe. As such they were in great demand and for centuries have been a major economic attraction on Russia's domestic and foreign markets.
Then came the period of 1960 - 1970s when the total yield dropped by nearly ten times (down to 1 - 3 thous. tons a year). The drop was caused by the felling of the most valuable forest plantations and today cedar nuts come from mainly inaccessible areas (at rates of only 100 - 200 kg/ha)*. As experts point out, over the next few decades yields of such areas will begin to drop due to reasons of age and biological factors. And with the level of consumer demands being unlimited, effective steps have to be taken to replenish the sources of the "rare natural delicacy". The obvious solution of the problem lies in planting cedar forest-gardens.
And there are two ways of solving this problem: effective management of undergrowth plantation and starting
* See: Ye. Titov, "The Future of Siberian Cedar", Science in Russia, No. 2, 2004. - Ed.
what specialists call industrial grafting plantations with emphasis on scientific principles and research.
The first of these ways originally belonged to what was known as spontaneous "native" selection methods. In 18th - 19th centuries peasants in the Urals and Siberia "honored" cedars as fruit-trees and gradually cleared the ground from fir-trees, birches and damaged cedars clearing the ground for their "favorites". With plenty of sunlight and air crowns of cedars blossomed as never before and their crop yields-regular and abundant. According to a Ural expert of the mid - 20th century, Mikhail Petrov, almost every cedar at such plantations produced up to a thousand cones (some 20 kg of pure nuts). The productivity of such cleared lots was several times greater than of the untended "taiga" ones. In some years their yields reach 500 to 1,500 kg of seeds per hectare, and young cedar woods from 50 to 60 years of age yield about the same amounts of cones as mature taiga forests two centuries of age.
What are called the cultivated forest-gardens today stretch from the near-Ural region and up to the Yenisei River. In the Tomsk region, for example, they exist in large plots, forest "dachas". But the total area of such "plantations" in this country does not exceed 50 thous. ha (a little greater than one thousandth of the total territory of the areal of the Siberian cedar). And that means that this provides only a minor share of Russia's total crop of cedar nuts.
That being so, time has obviously come for cultivating new areas of taiga. Young cedars have "sprung up" now after half a century of selective and clean cuttings. But under the dense cover of leaf-bearing trees young cedars yield no crops. And that means that the timely removal of foliage canopy would help boost crop yields
of nut, and that in regions with developed roadnets.
As experts point out, one even more effective solution consists in developing "specialized" plantations on the principles of genetic selection. As different from "near-village" cedar plantation consisting of the best trees of limited numbers of select species, scientists now focus their efforts on a rich spectrum of what they call "plus samples" selected from tree populations of "ununiform" origin. Their concentration on a certain area by way of vegetative selection (cloning) makes it possible on graftage of only 20 - 25 years to obtain considerable crops of nuts- 3 to 4 decades earlier than on plantations of the earlier type.
This becomes possible thanks to the preservation in the vegetative progeny of the seed productivity of trees and their free location on lots (6x6 or 6x8 m) but mainly due to the composition of clones. The Siberian cedar is a monoecious species with both female and male generative organs forming upon it. But their numbers and ratios are not the same: by the prevalence of male shoots, or sprouts, over female ones one can distinguish species of different reproductive or mixed type.
Such reproductive "specialization" guarantees the existence of the species in seed proliferation. The main function of the female plants is to produce seeds. These are mostly high-yielding genotypes. In natural plantations the dependability of cross-pollination with them is ensured by cedars of the male and mixed type. They produce a vast mass of viable pollen with modest crops of nuts, as has been established by scientists of the Chair of Forestry of the Voronezh State Forestry Technology Academy. And large crops of nuts can be produced only though the interaction of plants of different types.
The composition of clones is determined on the basis of the distance separating the plots from dependable sources of proliferation-adult cedars. In the areal of a given species, at the close location of pollinators (up to 1 km on plain ground and up to 400 m on slopes in the mountains) they clone female species-chiefly positive by the abundance of high-quality seeds. When there is not enough of natural pollinators high yields can be obtained by placing on plantations from an early age of different clones (optimal ratio of high and medium yields 3:1).
In natural cedar forests abundant crop occur once in four years, and even in 7 to 10 years. The thing is that a tree spends plenty of plastic substances on the formation of cones and nuts and these "spendings" have to be replenished. The "replenishment" period depends on the individual fea-
tures of a genotype and the state of the environment during maturation of crops.
An important advantage of plantations is the possibility of getting nuts on a regular basis. For that it is desirable to clone not only "copies" which often yield seeds and pollen, but also high-yield ones in certain seasons which are "non-productive" for most cedars.
The geography of the possible location of cedar forest-gardens is very broad, but the best effect is attained in the zone of ecological optimum of the species which is the southern plain-land taiga of Western Siberia and the Altai-Sayan low-mountain relief (up, to altitude of 800 m) with their fertile soils and conducive regimes of warm weather and precipitation. And the climate and weather conditions are also favorable in the belt of conifer broad-leaved forests. And in European Russia's forest-steppe zone, with too much heat and not enough moisture, it is more preferable to graft European cedar to common pines (more drought-resistant than Siberian cedar). And the seedling stock, quick-growing and adapted to the local conditions is a good incentive for the development of scions (graft). For example at experimental plots of our Academy in the Voronezh Region no less that 40 cones (400 - 600 g of nuts) maturate on a 10-year graft. After 20 years the yields exceed 3 kg and then continue to grow.
The establishment of such plantations will put the branch onto a new qualitative level-variety grading. This approach to the forestry branch became realistic back in the 1990s when experts in different regions selected in a planned manner the best trees, tested their vegetative progeny, planted grafting plots and developed the theoretical basis of formation of cedar forest-gardens. In the Altai Republic alone-the genetic center of origin of the Siberian cedar, such plots were opened up at the rate of 5 - 6 a year. Unfortunately this work was later abandoned because of the lack of federal funds and this will have a negative effect on cedar nuts production in this country as a whole.
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