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Comparison of stand structure and growth between artificial and natural forests of Pinus sylvestiris var, mongolica on sandy land 总被引:2,自引:0,他引:2
ZHUJiao-jun FANZhi-ping ZENGDe-hui JIANGFeng-qi MATSUZAKITakeshi 《林业研究》2003,14(2):103-111
Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in “Three North” regions (North, northwest and northeast of China), but many prob-lems occurred in the earliest Mongolian pine plantations in 7hanggutai, 7hangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively.Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11,22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings‘‘ disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas. 相似文献
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ZHU Jiao-jun KANG Hong-zhang TAN Hui XU Mei-ling WANG Jun 《林业研究》2005,16(4):253-259
Natural regeneration in Mongolian pine, Pinus sylvesttis var. mongolica, forest at Honghuaerji of China (the original of the natural Mongolian pine, forest on sandy land) was studied in 2004. The total mean values of regeneration indexes were higher in mature stands (more than 80% individual stems were older than 50 years), the maximum of regeneration index reached 29 seedlings, m^ 2, with lowest values in the younger stand, e.g., in 32-year old and 43-year old stands. The stand age was an important factor determining the natural regeneration, which was the best in the older stands in this investigation (e.g. about 80-year old). The regeneration index seemed not to be closely in relation to canopy openness although Mongolian pine is a photophilic tree species. In each type of gaps, natural regeneration was very well. Regeneration indexes were satisfactory at the south and east edges in the circle gaps; and at the east edge of the narrow-square gaps. Results indicated that Mongolian pine, seedlings could endure shading understory, but it would not enter the canopy layer without gap or large disturbance, e.g., fire, wind/snow damage or clear cutting etc. These results may provide potentially references to the management and afforestation of Mongolian pine, plantations on sandy land in arid and semi-arid areas. Researches such as the comprehensive comparisons on regeneration, structure and ecological conditions and so on between natural Mongolian pine, forests and plantations should be conducted in the future. 相似文献
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Sandy forest-steppe ecotone in Baiyinaobao Natural Reserve of Inner Mongolia Autonomous Region of China is one of the special landscape types in forest-steppe vegetation zone in China. Vegetation landscape types, landscape patches and patch size were measured by the field investigation, forest photograph, and airscape. The structure of landscape patches in sandy forest-steppe ecotone, including composition structure, and size structure, was studied and the dynamics and transformation of landscape patches were analyzed. The data obtained in this study could provide theoretical basis for the research on vegetation landscape in forest-steppe ecotones and other vegetation types. 相似文献
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孢粉、考古及历史文献等资料显示,先秦两汉时期中国北方地区林木分布广泛,种类繁多。春秋以后北方多数地区气温有所波动,树种结构也相应地发生了变化。春秋至东汉时期,东北地区受气候变冷影响,乔木植被中针叶林比率有所增加,落叶阔叶林减少,同时森林分布范围缩小;黄淮海平原地区针、阔叶乔木随气候变化互有消长;黄土高原区未有森林生长,河谷及山地植被以阔叶树种占优的混交林为主。除气候因素外,人类活动也影响着天然植被的变化。受秦汉时期经济、政治、军事等活动的影响,除东北地区天然林木保存较好外,北方其余地区林木破坏较为严重。 相似文献
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Effects of drought stresses induced by polyethylene glycol (PEG) (0.0%, 10%, 15%, 20%, 25%, and 30%, with four replicates)
on germination of Mongolian pine (Pinus sylvestris var. mongolica) seeds produced in plantations (southern Keerqin sandy land) and natural forests (Hulunbeier sandy plain) were observed.
The results indicated that the seeds from both provenances did not germinate when PEG concentration was more than 25%. The
time of initial germination and that of its completion of stressed seeds from both provenances were delayed when compared
with the unstressed seeds. The germination capacity and germination rate of natural seeds were significantly higher than those
of plantation seeds for all treatment levels (P < 0.05). The mean growth rates of radicle and hypocotyl from natural seeds were significantly higher than those from plantation
seeds at all treatment levels below 20% PEG treatment (P < 0.05). The ratios of radicle to hypocotyl of 20% PEG treatment were significant higher than those of the corresponding
controls for both provenances (P < 0.05). These results suggested that Mongolian pine seeds/seedlings had stronger resistance to PEG drought stresses; 10%
PGE stress did not significantly influence germination. Natural seeds exhibited more resistance to PEG stress than plantation
seeds. It was concluded that drought stress on seed germination might be one cause of obstructed natural regeneration of Mongolian
pine plantations on sandy land. It is recommended that natural seeds be used for afforestation, and light drought stress (e.g.,
10% PEG stress) may be useful in improving seed germination and the growth of radicles and hypocotyls. 相似文献
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Establishing evaluation index system for desertification of Keerqin sandy land with remote sensing data 总被引:2,自引:0,他引:2
科尔沁位于我国东北部,地处东北平原向内蒙古高原的过渡地带(42°41'-45°15'N,118°35'-123°30'E),是受荒漠化影响较重的地区。利用外业调查数据,依据地表形态和生态状况的变化,确定了植被盖度、裸沙地占地百分比和土壤质地3 项评价指标,并建立了基于遥感的科尔沁沙质荒漠化评价指标体系,其中裸沙地占地百分比用混合像元分解的方法获得。利用外业调查的数据对该指标体系进行验证,结果表明该指标体系适于研究区域的荒漠化评价。表4参11。 相似文献
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为探寻科尔沁沙地东南部草地生产力自然恢复的主要限制因素,该文采用3因素2水平析因设计研究了水、氮、磷添加对沙质草地的影响。8种处理分别为添加水(W)、加氮肥(N)、加磷肥(P)、加水+氮肥(WN)、加水+磷肥(WP)、加氮肥+磷肥(NP)、加水+氮肥+磷肥(WNP)和对照(CK),每种处理6次重复,随机分配在48个4m×4m的样方中,样方之间留2m缓冲带。研究结果表明:科尔沁沙质草地生产力的恢复受氮素的限制,与水和磷无关;2005年生长季所有添加氮肥的样方,生物量和地上净初级生产力均较对照明显增加(P<0.05);禾本科根量在地下生物量中占优势。受限于地下生物量测定,目前的研究可能低估了我国北方草地的净初级生产力。 相似文献
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以松溪县为例,分析闽北重点林区天然林资源和经营现状,针对当前存在的天然林总量不足、分布不均、经营粗放和技术措施落后等问题,提出相应的经营管理对策。 相似文献
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文章叙述了通辽市沙化土地现状及变化情况,对其沙化土地状况进行了评价,并提出防治对策。 相似文献
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Margot Vanhellemont Joris Van Acker Kris Verheyen 《Scandinavian Journal of Forest Research》2016,31(6):561-567
The conversion of homogeneous plantations of conifers to mixed or broadleaved forests is part of sustainable forest management strategies in Western Europe. For the conversion of pine plantations on sandy soils, birch seems a convenient choice. Yet, thus far, little is known about the growth of mature birches outside Northern Europe. We sampled 32 birch trees in forests throughout the sandy ecoregion in northern Belgium at sites that varied in soil and local stand conditions. Half of the birches showed the characteristic pattern in growth (expressed as basal area increment) with a sharply increasing growth till around the age of 25 years followed by a steep decrease in growth. The growth was strongly related to tree age and crown dimensions, only weakly related to soil conditions, and not related to the local stand conditions. 相似文献
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历史时期中国竹林分布对气候变化的响应 总被引:5,自引:2,他引:5
气温是决定植被分布的一个重要因素。通过研究我国历史上各个时期竹林分布范围的变动状况表明 ,历史上我国的气候条件经历了温暖和寒冷的几度波动 ,竹林的分布范围也相应地发生着变化。在气候较温暖的秦汉时期、隋唐时期和元朝时期 ,竹林分布到较高纬度的地方 ;在气候较寒冷的魏晋南北朝时期、南宋时期及明清时期 ,竹林的分布北界则向南移动。在温室效应引起的全球气候变暖的前景下 ,未来我国竹林的分布北界将可能会逐步北移。 相似文献
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Nitrogen was the main limiting nutrient of net primary production in the southeastern Keerqin Sandy Lands, Northeast China. Species richness declined and biomass increased after five consecutive years of nitrogen fertilization of these sandy grasslands (2004-2008). After fertilization had been stopped for three years (2009-2011), we surveyed vegetation on previously fertilized plots to quantify changes in commu- nity composition. Respect species richness showed an increasing trend over time since the cessation of fertilization. Respect vegetation height and coverage showed decreasing trends over time since the cessation of fertilization. Species composition changed after fertilization ceased, the dominant species shifting from Cannabis sativa, Phragmites communis and Chenopodium acuminaturn in 2008 to Cannabis sativa, Phragmites communis and Artemisia scoparia in 2011. Dominance of dominant species declined from 66.2% in 2008 to 57.5% in 2011. The importance value of annual plants in the earlier nitrogen addition plots was higher than in control plots, but the differences were not significant in 2011. The importance value of perennial plants differed significantly between treatments from 2009 to 2011. The reversion rate not only differed be- tween community characteristics, but also between functional groups in the same community characteristic. Although the residual effect of nitrogen addition on vegetation was still observed three years after fertilization ceased, the vegetation showed signs of recovery. 相似文献
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The role of ectomycorrhizal fungi in alleviating pine decline in semiarid sandy soil of northern China: an experimental approach 总被引:1,自引:0,他引:1
Jiao-jun Zhu Feng-qin Li Mei-ling Xu Hong-zhang Kang Xiang-yun Wu 《Annals of Forest Science》2008,65(3):304-304
The decline of Mongolian pine (Pinus sylvestris var. mongolica) trees on sandy land in northern China has caused serious ecological concerns. Mongolian pine is an ectomycorrhizal fungus (ECM)-dependent species. Three ECM species (Boletus sp., Lactarius deliciosus and L.sp.) were collected from Mongolian pine plantation stands to test their beneficial effects on Mongolian pine seedlings and their responses to environmental factors such as pH, drought stress and temperature. The results indicated that ECM inoculation significantly increased the rate of ECM colonization and the length of seedling shoots. The three ECM could grow in a pH range from 4 to 7, but did not grow under heavy drought stress (?1.53 MPa). High temperatures (over 37 °C) caused death of ECM. When related to soil pH, soil water content and temperature in the Mongolian pine plantations, water conditions and temperature were unfavorable for ECM growth in surface soil, but suitable in deeper soil. Therefore, it was concluded that the failure of natural regeneration in Mongolian pine plantations might be influenced by the lack of ECM in the surface soil because of high temperatures causing ECM death. Moreover, the majority of the root area is distributed in deeper soil, which alleviates the stresses on ECM development and arrests pine decline; this is beneficial for tree growth. 相似文献
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中国热带林资源和利用现状及2000年发展前景朱敏慧(中国林科院科信所,北京100091)1中国热带林资源概况中国的热带林处于热带北缘,属干湿交替型的热带向干热带过渡地带,按区域划分大体可分为3个地带:(1)东部过渡性热带季雨林、雨林区,包括福建东南部... 相似文献
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三北防护林体系工程发展现状及对策 总被引:2,自引:0,他引:2
为了改善生态环境,中国政府于1978年开始在三北地区建设林体系。15年来,共计完成人工造林1330hm^2,零星植树30亿株,森林被覆盖率已由15年前的5.005%提高到8.6%,不仅取得了明显的生态效益和经济效益,也走出一条有中国特色的林建设道路。今后的发展对策为:强化政府行为;调整经济政策;优化林种树种结构;增加科技含量。 相似文献