catalogue
1. Living habits
2. Morphological characteristics
3. Distribution range
4. Planting techniques
5. Main values
6. Crop cultivation
Living habits
Poplar likes light. Temperate climate and cold tolerance are required. The requirement for water is very strict, because its photosynthesis and transpiration are higher than those of other broad-leaved trees. Poplar seeds are small, and the capsules will crack when they mature, so the seeds are collected from cutting ears or ground. Seeds are easy to lose germination ability, so they should be sown with the harvest.
morphological character
The terminal buds of poplar twigs have more than two bud scales. Simple leaves alternate, ovate or suborbicular. Catkin, dioecious. Capsule seeds are small and have crests. In China, the distribution range spans 25 ~ 53 N and 76 ~ 134 E, covering northeast, northwest, north and southwest. In recent years, the introduction of Populus deltoides has moved the cultivation area south to the plains of Hubei, Hunan and other provinces. Populus euphratica is divided into five groups: Populus euphratica, Populus alba, Populus nigra, Populus cathayensis and Populus macrophylla.
distribution range
Poplar is the most widely distributed and adaptable tree species in the world. Mainly distributed in temperate and cold temperate forest trees in the northern hemisphere, latitude 22-70, altitude as low as 4800 meters.
Poplar natural forest covers an area of more than 20 million hectares (poplar is the dominant tree species in the world), and there are about 100 natural tree species. The countries with the widest distribution of natural poplar varieties are Russian, China, Canadian, American, Italian, French and other countries.
Planting technique
The fast growth and high yield of poplar depend on improved varieties and good methods, and only with the cooperation of good methods can improved varieties give full play to their yield-increasing potential. There must be many measures to improve the yield of poplar plantation, and only comprehensive optimization and high-yield cultivation measures can achieve the highest yield. The characteristics of fast-growing and high-yield cultivation techniques are to exchange higher input for the highest output. This high-yield cultivation mode emphasizes:
(1) Adopt improved poplar varieties to exert genetic benefits;
(2) Improve afforestation technology, plant strong seedlings and choose suitable density;
(3) Take the excellent materials without knots as the cultivation target, and timely and reasonably prune them.
1. Selection of afforestation site: the afforestation site should be selected in floodplain, terraced fields or abandoned rivers, or cutting land, low-yield forest land and farmland, and returning farmland to forests.
2. Soil preparation: (1) all-round deep ploughing and soil preparation; (2) deep turning of strip; (3) large hole soil preparation; (4) Deep cultivation of foreign soil.
3. Afforestation with strong seedlings: It is best to use strong seedlings with DBH 3-4cm and height of 5-6m for high-yield forests.
4. Afforestation method: Poplar planting generally advocates "three big ones and one deep one", that is, large spacing between plants, large holes, large seedlings and deep planting.
5. Density: The plant spacing of 5m, 6m, 4m, 8m, 6m, 7m and 7m can be adopted for cultivating large diameter timber.
6. Loosening soil and weeding: after afforestation, loosing soil and weeding should be done in time to eliminate early, small and small weeds, once a year 1-3 times. The loosening depth is generally 5- 10Cm.
7. Reasonable irrigation: In order to achieve high yield of poplar, the stand should supply 800- 1000 mm of water every year.
8. Rational fertilization: Nitrogen fertilizer is mainly applied to poplar, and farmyard manure is used as base fertilizer in soil with low organic matter content, and topdressing nitrogen and phosphorus fertilizer will obviously promote the growth of poplar.
9. Pruning: (1) reshaping: it is to cut off the competitive side branches that affect the growth of the top main shoot to ensure that the trunk is straight. (2) Pruning: Pruning is to cultivate moderate materials such as plywood and match industry for processing. (3) Pruning shoots sometimes grow in situ due to the stimulation of pruning, so these shoots should be cut off as soon as possible.
10, thinning and main cutting: (1) thinning: It is feasible to cut in time for stands with high young forest density. (2) Main cutting: refers to the age when the stand reaches maturity and is cut.
Main value
The industrial utilization of poplar mainly includes: large-diameter poplar is mainly used to produce plywood, laminated veneer lumber and furniture; Small-diameter poplar is used to produce fiberboard, particleboard, paper making and matches.
Generally, large plant spacing is used for planting. In developing countries, close planting is the main method, and the rotation period is short, producing medium-diameter wood for civilian use. There are some transitional types between the two.
Poplar can be widely used in ecological protection forest, three-north protection forest, agriculture and forestry protection forest and industrial timber forest. Poplar is an excellent tree species for road greening and landscape. Its characteristics are tall and majestic, neatly marked, fast forest formation, sandstorm prevention and waste gas absorption.
plant culture
Symbolic significance of poplar: Poplar stands tall and straight, symbolizing integrity and justice; At the same time, poplars are always so tall and strong, symbolizing the indomitable fighting spirit.