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991.
992.
A field trial was conducted investigating the single season growth response of 1+0 313 PSB Engelmann spruce (Picea engelmannii Parry ex Engelm.) and lodgepole pine (Pinus contorta Dougl. ex Loud.) seedlings planted into two different soil thermal regimes at three high-elevation locations spanning 200 km in the Engelmann Spruce-Subalpine Fir (ESSF) biogeoclimatic zone in the Cariboo Mountains of central British Columbia. Temperature treatments represented the extremes of soil temperature commonly found in high-elevation clear-cuts. A warm soil treatment (clear day, mid-afternoon soil temperature in mid-summer of 18 to 25 °C at –10 cm) consisting of a bare mineral soil hummock (average dimensions of 100 cm × 100 cm × 40 cm) was contrasted with a cool soil treatment (clear day, mid-afternoon soil temperature in mid-summer of 10 to 13 °C at –10 cm) comprised of organic forest floor overlying mineral soil. By the end of the growing season, seedlings of both species planted into the warm treatment generally exhibited greater root, stem, foliage, and total seedling biomass than cool treatment seedlings. Measurements of root growth at 30, 60, and 90 days after planting showed that total root number and total root length were consistently greater for warm treatment seedlings than for cool treatment seedlings. Root growth was greater from the bottom rather than from the side of the root plug for all seedlings. These results suggest that the effect of low soil temperatures on outplanted styroblock conifer seedlings is pronounced and may be limiting growth performance in high-elevation plantations in British Columbia. We recommend silvicultural treatments that secure natural regeneration, ensure that warmer microsites are always planted, and utilize seedling stocktypes able to make rapid lateral root growth into warmer surface organic horizons. 相似文献
993.
lNTRODUCTIONTherhythInofKorcanpinegrowingandtrpearchitectUreissubjectedtoitsownl1crcd-ityandforeststructUre.Tl1cil11portantefTcctsofgapdynamicsarethereasonsthatmaketl1cKoreanpinetrceformhighqualityoftimbcr.Whilecurrentn1anagemcntofKoreanpincforestmainlyfocusesonpurestand,thccco-logicalrelationshipsbetWcenKoreanpineandothcrsPecicsinaconununityareneglected,thcprimitivebiologicalconditionislost.TheKo-reanpinetrecsinplantationcasilydivergeonthctOpofmainsten1,thesescverelyaITectthcgrOedqu… 相似文献
994.
Combined production of timber and forage species is considered to be a desirable land-use system to offset some of the current land management problems of Italy. This paper reports the early results of a study on intercropping young plants of walnut with alfalfa (Medicago sativa L.), with or without polyethylene mulching, in an experimental plantation in central Italy. Two genotypes of walnut were used:Juglans regia L. and the French hybrid NG23×RA. The seasonal changes of absolute and relative growth rates of walnut stem diameter and apical shoot length were investigated.During both growing seasons, alfalfa intercropping strongly decreased walnut growth, whereas polyethylene mulching promoted stem height and diameter growth. Stem growth of intercropped-and-mulched walnut was the same as that of sole walnut under clean cultivation management. The use of polyethylene mulching reduced or avoided the competitive effect of associated alfalfa on walnut growth. During both growing seasons, the intercropped-and-mulched walnut had higher relative growth rates than intercropped-unmulched walnut. The results show the effectiveness of polyethylene mulching in promoting early growth of walnut, even when intercropped with alfalfa during early stages of plantation establishment. 相似文献
995.
Maarit Kytö 《New Forests》1993,7(3):275-286
The effect of Lygus rugulipennis Popp. feeding and artificial damage on the apical bud of Scots pine (Pinus sylvestris L.) late in the growing season was studied on two-year-old seedlings. Lygus feeding in late July and August caused inhibition of bud formation in the subsequent year's shoots, which led to loss of apical dominance and formation of interfascicular buds. Mechanical damage caused by piercing the apical bud with a needle in July, August and October produced scars and malformations on subsequent year's shoots and buds, but did not inhibit bud formation. Damage to the apical meristem could not be detected visually on the dormant bud before shoot elongation. 相似文献
996.
杉木幼林年生长规律及气候因素对生长的影响,是合理制订杉木产区区划,改善杉木造林规划设计布局,正确实施经营管理措施的基础。 本项研究,将全国杉木西部试区的四川高县作为试验点,从1985~1988年,连续4年在5~8年生不同密度林分中,作了胸高直径及树高生长的旬期定期观测。经对这些实验数据作均值处理,聚类分析,关联分析和多元回归分析结果表明:对生长在中国杉木中带西部产区,处于中亚热带湿润气候区环境条件下的杉木幼林年生长规律的论证及对影响生长的主要气候因子的分析判断和预测,具有可靠性和区域代表性。 相似文献
997.
998.
中国木材产业规模化经营的战略性思考 总被引:1,自引:0,他引:1
归纳了规模经济效应与产业成长的关系,分析了木材产业规模化经营对产业变革的意义;通过对中国木材产业规模化经营现状的分析,指出了当前所存在的问题;最后,就如何实现中国木材产业的规模化经营进行了战略设计,并提出了战略实施的相关支持性条件. 相似文献
999.
1000.
配方施肥对毛竹林新竹生长及经济效益的影响 总被引:2,自引:0,他引:2
通过"3414"施肥试验,研究了不同N、P、K配方施肥对福建三明毛竹林新竹生长及竹林经济产出的影响。结果表明,N、P、K不同配方对新竹的成竹率、新竹胸径与新竹产量以及对竹林经济产出的影响差异显著。14个配方处理中,N2P3K2的新竹数最高,为对照的1.69倍;N2P2K2的新竹胸径和产量均为最大,分别为对照的1.09和1.91倍,且新竹叶片的N、P、K、Mg浓度最为均衡。该试验条件下,施尿素540 kg/hm2、硫酸钾135 kg/hm2、过磷酸钙450~675 kg/hm2,能较为有效地促进新竹生长与产量持续。各配方施肥对毛竹林的增产幅度为18.1%~192.4%,增产效益明显,N2P2K2的竹林产值最高,是对照的2.92倍,资金产出率(产投比)前3位为N2P2K2、N2P3K2和N2P2K3,分别是3.83,3.43和3.26,N素对新竹生长的影响最大,缺N素、P素试验的资金产出率低于无施肥处理。 相似文献