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杨树超短轮伐期经营的生产力及材性的研究 总被引：16，自引：0，他引：16
以美洲黑杨２个无性系为供试材料，研究杨树超短轮伐期经营中地上部分生物量生产、分配模式、Ｎ、Ｐ、Ｋ的输出量及材性。结果表明，在３种密度和３种轮伐期的组合中，２个无性系均以造林密度为１００００株·ｈａ－１、轮伐期为３年的林分生物生产力最高，Ｉ－６９杨为１０．５２ｔ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨约为１２．００ｔ·ｈａ－１·ａ－１；在生物量的分配比率和作为造纸材的经济生物量上也以这种组合模式最为合理，经济生物量最大，Ｉ－６９杨为７．１４ｔ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨为８·４７ｔ·ｈａ－１·ａ－１。养分输出量的多少与林分的生物量生产和分配比率密切相关。轮伐期为３年，密度为１００００株·ｈａ－１的林分Ｎ、Ｐ、Ｋ的输出量最高，Ｉ－６９杨为３３．９７ｋｇ·ｈａ－１·ａ－１，ＮＬ－８０３５１杨为３８．５０ｋｇ·ｈａ－１·ａ－１，但ＮＬ－８０３５１杨每生产１吨经济生物量所输出的Ｎ、Ｐ、Ｋ总量略低于Ｉ－６９杨。杨树超短轮伐期经营中生产出的木材都可用作中、低档的造纸原料，其中Ｉ－６９杨的制浆性能优于ＮＬ－８０３５１杨。 相似文献
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赵体顺 《中南林业调查规划》1988,(3)
目前我国对农田林网的研究多集中在防护效益和粮食产量方面,对农田林网中林木的物质生产、积累与分配以及光能利用等则研究较少。揭示农田林网生态系统中林木的物质生产、积累、分配、循环的规律有助于挖掘土地生产潜力,提高光能利用率,进一步提高农田林网生态系统的生产力。杨树是华北平原农田林网的主要树种,所以我们对杨树生物量进行了初步研究。 相似文献
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在农田林网中进行Ｉ－２１４杨、加杨、小美旱杨、北京杨４个杨树品种的造林对比试验，２０ａ生Ｉ－２１４杨的平均胸径为４２．１ｃｍ；平均树高为２７ｍ，平均单株材积为１．３６９６ｍ３，约是加杨、小美旱杨、北京杨的４～８倍。 相似文献
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以望江县为例，探讨皖中沿江地区农田林网的合理模式，认为农田林网的主带距为４５０－６００ｍ，副带距５００－９００ｍ，８０％以上网格面积在２０－５３．５ｈｍ＾２之间。林带疏透度０．３，江堤防护林应乔灌草相结合。 相似文献
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平原农田林网建设的理论与实践 总被引：1，自引：0，他引：1
通过对农田林网建设实践的调查分析，总结出农田林网的4种主要建设模式和三大效益，并对农田林网建设存在的问题及如何合理配置进行了探讨，提出了建设好农田林网的对策。 相似文献
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对中原地区农田林网的调查表明,应用D、D~2H 与林木生物量之间的相关关系,可以估算该地区林网的生物量。调查还表明,以人工复合生态系统林网生产力较高,达28.1848吨/公顷·年,生物现存量达42.3187吨/公顷,是中原、华北地区可以推广的农田林网模式。 相似文献
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针对农田林网采伐还林难的现状，对湖北省公安县农田林网建设情况进行了综合调研，调查涉及16个乡镇以及40多个行政村。调查结果显示：农田林网建设面临空前严峻的挑战，如不采取有力措施，5年内农田林网将萎缩80％以上，花几十年时间、几代人精力精心构建的农田林网格局将不复存在，届时农业丰产稳产将得不到保障，后续生态灾难更是难以预料。 相似文献
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浅议振兴平原地区农田林网建设 总被引：1，自引：0，他引：1
农田林网是平原绿化的主体,也是农业生产的屏障。本文分析了农田林网的效益,指出了农田林网建设中存在的问题,提出了振兴平原区农田林网建设的建议。 相似文献
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海滨湿地杨树、柳树新无性系苗期耐盐性研究 总被引：3，自引：0，他引：3
在海滨湿地分别4个盐度梯度，12种杨树、柳树新无性系田间扦插试验结果表明：在苗期，不同杨树、柳树无性系的成活率、保存率、生长量等均与土壤含盐量呈负相关；在出苗期的耐盐能力，1-74杨、1-69杨可达0．241％，35杨为0．188％，J30-16、J35-13、J4-34、J31-17柳为0．089％，其余5个柳树无性系均在0．060％以下；在苗木生长期，其耐盐极限分别为0．343％，0．333％和0．201％。 相似文献
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Impact of spacing and rotation length on nutrient budgets of poplar plantations for pulpwood 总被引：2，自引：0，他引：2
IntroductionPoplarshavemanycharacteristicsSuitableforplantationcultureascomparedtootherforestspecies,suchasfastgroWth,adaptabifitytodifferentenvironmentalconditionsandtodifferentsilviculturalsystems,whichenabletheproductionoflargequantitiesofwoodinshortperiodsoftime.Poplarscanbeusedfordifferentformsofprocessingintimberindustry,aswellasinpulpandpaperindustryandasasourceofenergy(Gambles&Zsuffa1984,Moran&Nautryal1985,Fangetal1993).Sincesomepoplarcloneswereintroducedinthe1970"s,poplarshavebeent… 相似文献
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黑杨派杨树新无性系物候期及生物学特性观测研究 总被引：1，自引：0，他引：1
对黑杨派杨树I-63杨和I-69杨人工杂交获得的优良单株LH04-13,以I-69杨、I-63杨、南林895、中石7号杨等为对照营建试验林,观测研究各无性系萌芽展叶、生长、封顶落叶、开花结实等物侯期及生物学特性适应性、抗逆性等,以期为杨树无性系的选育及造林推广提供理论依据。 相似文献
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Forest plantations in the northeastern United States comprise a small proportion of the total forest area. Most plantations are typically softwood dominated and managed for sawlog and pulpwood production, while high-yield hardwood plantations for bioenergy feedstocks have not been as widely investigated. The objective of this study was to compare the biomass production of planted white spruce (Picea glauca (Moench) Voss) and hybrid poplar (Populus spp.) plantations (four clones) in monoculture, and in mixture of the two on a typical reforestation site in Maine. Three years following planting, hybrid poplar height and ground line diameter growth rates began to diverge among clones, and by 6?years, the Populus nigra?×?Populus maximowiczii (NM6) clone clearly outperformed three Populus deltoides?×?Populus nigra clones (D51, DN10 and DN70) both in pure stands and in mixtures with white spruce. In mixture, we found the yield of white spruce to decline as the yield of hybrid poplar increased. Overall, yields of white spruce monocultures were comparable to those reported in eastern Canada, while the hybrid poplar biomass yields were substantially lower than those reported from studies on abandoned agricultural lands, likely due to the harsher soil conditions at our site. The dominance of rocky and poorly drained sites (like the one tested in this study) across Maine will likely limit the feasibility of widespread hybrid poplar plantations, and thus constrains their potential use as a bioenergy feedstock. 相似文献
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In a poplar clonal plantation with different species and hybrids, established at 13,333 cuttings ha?1, biomass production was assessed at the end of the first rotation (3 years) and the potential of the different clones for sugar production was evaluated. The highest biomass production was observed for clones ‘AF2’ and ‘Viriato’ (46.5 and 42 t dm ha?1, respectively). After a mild acid pretreatment and an enzymatic saccharification, the highest sugar digestibility was found for ‘Viriato’ and ‘Unal’. A clear relation between sugar digestibility and xylan removal during pretreatment was observed, while no relation with lignin content was found. Taking into account the results, the highest production of sugars per hectare was estimated for the poplar clone ‘Viriato’, being 18–48% higher than that achieved with the other clones. Therefore, this clone is a promising candidate to be used as feedstock for sugar production in a forest biorefinery. 相似文献
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Forty-nine new poplar clones, bred in Belgium and screened there for resistance to bacterial canker caused by Xanthomonas populi, were additionally screened in southern England, using British isolates of the bacterium. Thirty-five of the test clones ranked better than the clone ‘Boelare’, which is already registered in the UK as an approved clone, and is regarded as having acceptable resistance. The registered clone ‘Ghoy’ was more susceptible, and outranked only four test clones. Preliminary measurements of canker length and stem girdling index showed differences between five bacterial isolates. 相似文献
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To improve the productivity of poplar plantations, a field experiment of split-plot design with four tree spacings and three poplar clones was established, and four soil enzyme activities and microbial biomass were monitored in the trial.Soil enzyme activities, in most cases,were significantly higher in topsoil(0–10 cm) than in lower horizons(10–20 cm).Soil cellulase, catalase and protease activities during the growing season were higher than during the non-growing season, while invertase activity followed the opposite trend.Soil invertase, cellulase and catalase activities varied by poplar clone but soil protease activity did not.Cellulase and protease activities in the plantation at 5×5 m spacing were significantly higher than in the other spacings.The highest catalase activity was recorded at 6×6 m spacing.At the same planting density, invertase activity was greater in square spacings than in rectangular spacings.Soil microbial biomass was also significantly affected by seedling spacing and poplar clone.The mean soil MBC was significantly lower in topsoil than in the lower horizon, while MBN showed the opposite pattern.Significantly positive correlations were observed among soil cellulase, protease and catalase activities(p0.01), whereas soil invertase activity was negatively and significantly correlated with cellulase, protease and catalase activities(p0.01).Soil microbial biomass and enzyme activities were not correlated except for a significantly negative correlation between soil MBC and catalase activities.Variations in soil enzyme activity and microbial biomass in different poplar plantations suggest that genotype and planting spacing should be considered when modeling soil nutrient dynamics and managing for long-term site productivity. 相似文献
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Disease prevention, biodiversity, productivity improvement and ecological considerations are all factors that contribute to increasing interest in mixed plantations. The objective of this study was to evaluate early growth and productivity of two hybrid poplar clones, P. balsamifera x trichocarpa (PBT) and P. maximowiczii x balsamifera (PMB), one improved family of Norway spruce (Picea glauca (PA)) and one improved family of white spruce (Picea abies (PG)) growing under different spacings in monocultures and mixed plots. The plantations were established in 2003 in Abitibi-Témiscamingue, Quebec, Canada, in a split plot design with spacing as the whole plot factor (1 × 1 m, 3 × 3 m and 5 × 5 m) and mixture treatments as subplot factor (pure: PBT, PMB, PA and PG, and 1:1 mixture PBT:PA, PBT:PG, PMB:PA and PMB:PG). Results showed a beneficial effect of the hybrid poplar-spruce mixture on diameter growth for hybrid poplar clones, but not for the 5 × 5 m spacing because of the relatively young age of the plantations. Diameter growth of the spruces decreased in mixed plantings in the 1 × 1 m, while their height growth increased, resulting in similar aboveground biomass per tree across treatments. Because of the large size differences between spruces and poplars, aboveground biomass in the mixed plantings was generally less than that in pure poplar plots. Leaf nitrogen concentration for the two spruce families and hybrid poplar clone PMB was greater in mixed plots than in monocultures, while leaf nitrogen concentration of clone PBT was similar among mixture treatments. Because of its faster growth rate and greater soil resources demands, clone PMB was the only one showing an increase in leaf N with increased spacing between trees. Fine roots density was greater for both hybrid poplars than spruces. The vertical distribution of fine roots was insensitive to mixture treatment. 相似文献
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In order to identify the optimum cutting density for producing the highest number of plantable seedlings of poplar clones,
a split-plot randomized block design was used to establish four cutting densities in plots. Based on data on the survival,
leaf area, seedling height, caliper, and biomass of 1-year-old seedlings of clones Nanlin-95, Nanlin-895, Nanlin-1388 and
NL-80351, the growth characteristics and seedling quality under four cutting densities were analyzed. Results indicated that
the leaf area, stem and leaf biomass, and caliper of seedlings of all four poplar clones increased with the decrease in cutting
density. Leaf area index reached its highest level at the spacing of 40 cm×40 cm, while the aboveground biomass of the seedling
on an area basis increased as the cutting density increased. Seedling quality at low cutting density was higher than that
at closer cutting density. The quantity of first-grade seedlings (grade I) for clones Nanlin-95 and Nanlin-895 was achieved
at the spacing of 40 cm×50 cm; for NL-1388 and NL-80351, it was 50 cm×50 cm. According to the seedling quality and the number
of plantable seedlings produced, the suggested cutting density for these four poplar clones was 50,000 stems/hm2. 相似文献
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21个杨树无性系在湖北西部山区造林对比试验 总被引：1，自引：0，他引：1
在湖北省西部山区的宜昌市夷陵区进行了21个杨树无性系的造林试验。7年的调查结果表明,只要品种选择合适,杨树可以在山地生长,且速生、经济效益显著。‘鲁山’杨、‘M81—18’杨、‘351’杨、‘375’杨、‘中汉17号’5个优良无性系生长性状优良且稳定,不仅适合超短轮伐期经营,也适合中短轮伐期经营及短轮伐期经营。‘中嘉8号’、‘中嘉5号’、‘中监1号’、‘中监3号’、‘天演’杨、‘辽河’杨、‘108’杨的造林存活率低或者长势差。不宜在该山区推广应用。研究结果为湖北省西部山区营建杨树人工林提供了优良品种选择依据。 相似文献