earticle

영어

Korean pine (Pinus koraiensis Sieb. et Zucc.) is the climax species in primary forest mixed by it and the broadleaved tree species such as Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, Quercus mongolica and Acer mono in humid temperate areas in East Asia. It is a well-known high-quality timber production species which provided the main part of the 70% timber yield in China that was harvested in Northeast China’s forest area during 1950’ to 1990’s. Currently, it is also a very important edible pine nut production species, for its nut (seed) yield has occupied 69% of the pine nut yield in China during 2010 to 2019 and has become the most important support for local development for its high value in nut market. Specialized nut production plantation (nut garden) may be an effective approach, but compatible production of timber and seed by the same tree in the same forest may be the best approach in China for the following reasons: (1) morphology: mostly the cones of Korean pine are inserted on apical part of the crown and can be cultured in a relatively high stand density like the timber production plantation; (2) physiological feature: our investigations showed that the Korean pine support its cone growth by the enhanced photosynthesis and not by the redistribution of the nutrient from other organs; (3) economic demand: Korean pine timber, especially the large-sized clear wood, is also in good demand by the timber market but need a very long production rotation with a little income, but it can be compensate by frequent production of edible pine nut; (4) least but maybe most important, planting sites: there are just limited open area of planting sites for pure plantation but huge area of planting sites under canopy of secondary forest (at least 12 million ha). Breeding of Korean pine was started in 1950’ for the primary improved base of natural seed production forest selection and artificial seed forest establishment. The indeed breeding was started with the establishment of seed orchard in 1980’s but primarily for timber production. The breeding activities are mainly selection, but hybridization was conducted recently and has obtained some results. Fifteen national improved seed bases of Korean pine have been established in Northeast China’s forest region in forms of seed production forest and seed orchards (mainly the first generation, a few secondary generation). Many improved varieties in seed forest, seed orchard, family and clone level were selected but just national level approved Lushuhe Seed Orchard and others are all in provincial level approved or affirmed improved varieties, including 38 clones selected by nut indexes, 2 seed forest selected by timber and nut indexes, and 19 seed forests and/or seed orchard as well as 2 clones selected by timber indexes. There are also many clones and hybrids selected are waiting for approve or confirm. There are 2 types of sites for compatible forests of Korean pine in Northeast China: full-light or under-canopy, the former is limited by non-enough area land but rich land for later. A silvicultural system by site quality evaluation, density regulation, stem and top pruning, crop tree selection and operation with a series of control indexes of diameter, tree height, crown length and width, top pruning opportunities, stem pruning height, etc., has been establishment for full-light pure stand during the last 10 years but still in testing. An individual tree regulation system is in establishing for the under-canopy planted Korean pine tree but lagged by unproper policies of natural forest protection.