Introduction is an important way to make full use of natural conditions and improve the productivity of forest products(6 cell trays bulk). By the 1950s, due to the drastic increase in the cost of timber and the shrinking of the woodland area, the problems of increasing the wood output per unit woodland area and afforestation on non-forestry land mentioned the important schedule(72 cell plant tray), and forest tree breeding had developed rapidly.
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Now, some tree species such as poplar(8 cell trays bulk), eucalyptus, spruce, flowering pine (North American yellow cedar), and larch have far surpassed their respective natural distribution areas, spread all over the world, and become an important international afforestation tree species. In the south, according to trees, wetland pine, Pinus elliottii, Caribbean pine, Casuarina, etc(heavy duty plug trays). in the north, Robinia pseudoacacia, Japanese larch, etc. have become important afforestation tree species.(cheapest plastic 50 cell plug flats suppliers canada)
his work is of great significance for understanding the laws of geographic variation within tree species(12 cell trays bulk), for providing high productivity and adaptable provenances for afforestation areas, for zoning seed areas, and for providing breeding materials for further breeding(16.5cm plastic grow pots). Therefore, the occurrence and development of forest tree breeding are closely integrated with forestry production practices. Now, it has become one of the important measures for forest management.
Countries that lack wood or afforestation species attach great importance to the introduction work. But so far it is still the main method of tree species improvement(18 cell trays bulk). TDuring the "Sixth Five-Year Plan" period, China selected more than 11,000 superior trees from 13 coniferous species in the north and south, and established 136,000 acres of primary seed orchards throughout the country, providing more than 300 excellent families such as Chinese fir(v15 nursery pots).
(cheapest plastic 50 cell plug flats suppliers canada)The use of provenance variation plays a significant role in improving forest productivity and stability(36 cell trays bulk). Since the 1970s, China has conducted provenance tests on about 20 tree species. Experiments on Chinese fir, masson pine, Chinese pine, white elm, and arborvitae have achieved good results, and for the first time they have made seed zoning(19cm plastic grow pots). The selection of a sub-park has made significant progress abroad since the 1950s.
All or part of the main tree species for afforestation in the United States, Sweden, Finland, Japan and other countries are provided by the seed garden(40 cell trays bulk). After decades of efforts, the main foreign afforestation tree species, including trees with small natural distribution areas, such as Pinus radiata, Japanese larch, etc. have carried out this experiment, many of which have reached the intended purpose of the experiment(nursery tray). China has made great achievements in the introduction work.(cheapest plastic 50 cell plug flats suppliers canada)
Significantly increased seed production(40 cell tray in bulk), such as the seeds produced by the seed orchard affiliated to the North Carolina State University Fire Pine Improvement Collaboration Group, 271 in 1979, 50.5t in 1981, and 80.t in 1984, of which produced by the second generation seed orchard The seeds reached 2850kg: Now the second generation of seed orchards have started to be thinned out(germination tray price). According to incomplete statistics, about 50 countries have established seed orchards.
