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落叶松落叶病测报与防治指标的研究 总被引:1,自引:0,他引:1
1986—1989年对落叶松落叶病测报技术进行了系统研究,建立了落叶病测报管理决策支持系统。本系统可预测该病测报因子当年值;继而对全省和各地区平均病情指数,轻、中、重发病面积,应防面积发出长、中期预报;并可制定防治指标,编制防治计划,预测防治效益,资料查询等。 相似文献
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以Logistic模型为代表的种群(x)生长模型,仅依赖于时间(t),X=f(t),它是表达某一环境下生物过程的数学模型,其增长率参数(μ)为常数。本文发展了一种包含生态因子的广义Logistic模型,X=f(P,t),p表示生态因子,认为增长率是与生态因子有关的参数:μ=μ0f(p),该模型可以概括在不同环境下种群增长的重复试验,使用作物分期播种资料,建立了水稻干物质积累过程与生育阶段(时间)、播种期、太阳辐射、温度之间的关系,结果表明:该模型可以解释干物重变异的96.9%。 相似文献
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秦岭落叶松林土壤真菌种群及其生态特性研究 总被引:8,自引:0,他引:8
森林枯落物及土壤有机质分解主要靠微生物(尤其是真菌)来完成。微生物分布和活动是森林生产环境综合评价的主要依据之一[1]。开展森林土壤(包括枯落层)微生物生态研究对于森林保护,食品化工和医药工业产品的生产、开发提供新信息和菌种资源等有重要现实意义。本研... 相似文献
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以关帝山区8种林分密度(128、240、320、400、480、560、640和720株·hm-2)华北落叶松纯林为研究对象,分析了不同密度下华北落叶松天然更新优劣及其影响因子。结果表明: 更新指数随林分密度增大先升高后降低,中密度(400~560株·hm-2)林分更新效果明显优于过疏和过密林分;林下光环境、草本植物及凋落物对落叶松更新有双重作用,光照过强、草本植物盖度过大或凋落物过厚不利于林下更新,土壤有机质可使土壤质地松软、水分含量充足并形成低磷高氮环境促进林分更新;各因子对更新指数的影响依次为:土壤含水量(0.798)>全氮(0.621)>凋落物厚度(-0.597)>土壤孔隙度(0.504)>土壤有机质(0.493)>全磷(-0.404)>林下总光照(-0.274)>草本植物盖度(-0.021)。在后续森林经营中,可通过抚育间伐或补植将林分密度控制在480株·hm-2左右,并适当清理林下凋落物,改善土壤条件,促进华北落叶松天然更新。 相似文献
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不同地理种源长白落叶松生理生态特性的研究 总被引:5,自引:0,他引:5
在人工气候室中测定了10个种源长白落叶松二年生硬枝扦插苗的光合、水分生理生态参数。结果表明,不同种源的长白落叶松生理生态参数变异较大,但有一定规律可循。各种源的总光合速率>最大净光合速率>净光合速率>半饱和光强时的净光合速率>光呼吸速率>呼吸速率,只偶有例外。各参数中呼吸速率在各种源间变异最小,光呼吸速率变异较大,总光合速率变异最大。各参数在种源间的变化趋势均与净光合速率一致,即净光合速率大的种源其它参数也大,净光合速率小的种源其它参数也小。相对光呼吸在各种源间变异较大,其释放的CO2相当于光合固定CO2的总量的1/3。光补偿点、饱和点和半饱和点在各种源间的变异较大。水分利用率在各种源间的较大变异主要是由净光合速率引起,与蒸腾速率关系不大。净光合速率占总光合速率的百分比、呼吸功效、CO2补偿点、蒸腾速率和水势在各种源间变异不大 相似文献
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落叶松落叶病、枯梢病、褐锈病、兴安落叶松鞘蛾、落叶松球蚜、大蚜同为落叶松冠层的主要病虫害,但各具不同的生态位.不同害虫( 包括虫态) 、病害对落叶松冠层的作用时序均具交错出现、相互回避的现象.对生态环境亦各有不同选择,鞘蛾和球蚜大都喜于平坦、阳坡的林分,林分郁闭度0 .8 ~0 .5 为宜,尤以鞘蛾更喜于林缘和林分的天窗.通过对病虫害的综合作用研究,从落叶松生长期6 种病虫作用生命表中得知,自5 月下旬至7 月上旬,落叶松冠层中以害虫危害为主,自7 月下旬病害加入,使林木受害逐渐加重.仅有3 种害虫危害时,生命表中Kx 值为0 .016 ~0 .0197 ,病害加入后Kx 值增至0 .124 ,9 月7 日Kx 值达0 .26 .3 种病害的大量失叶时间为8 月,可连续影响3 年生长,影响最大者为第2 年,鞘蛾在5 月造成大量失叶. 相似文献
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以不同年龄、不同密度的落叶松(Larix olgensis)人工林为研究对象,基于19块标准地95株标准木的树干解析、枝解析的生物量数据,研究不同大小树木因子(胸径、树高、冠幅等)与单木各分量(树干、枝、叶)生物量之间的关系,应用统计分析软件建立落叶松单木各部分生物量的回归模型。利用单木各部分生物量回归模型方程估测落叶松人工林各林分的总生物量,并分析了不同年龄及林分密度下林分生物量的变化规律:林分的生物量随年龄的增加而不断增长,树干的生物量的比例是最大的,同时也是随着年龄的增长而不断的增加,而树枝和树叶的生物量的比例比较小,林分的生物量随林分密度的增加而不断增加。最后建立林分生物量模型,为落叶松人工林的研究提供基础资料,为了解落叶松人工林的生产力,对其进行合理经营提供科学依据。 相似文献
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不同年龄兴安落叶松树干呼吸及其与环境因子关系的研究 总被引:8,自引:0,他引:8
采用动态红外气体分析法研究了两个不同年龄兴安落叶松(Larix
gmelinii Rupr.)人工林内落叶松树干呼吸速率的季节变化,并分析了树干呼吸速率与环境因子的关系.两个年龄落叶松树干呼吸速率均是从春季到夏季逐渐升高,高峰值出现在7月(成熟林)和8月份(幼林),之后明显下降.幼林落叶松的树干呼吸速率(变化范围是1.99~6.15
μmol*m-2*s-1)显著高于成熟林(变化范围是1.52~3.38 μmol*m-2*s-1)(P<0.05).树干温度对树干呼吸影响较大,树干呼吸速率与树干温度呈指数相关关系;成熟林和幼林树干呼吸的Q10值分别为1.96和3.44.当空气相对湿度较低时,树干呼吸速率与其关系无明显规律,但当空气相对湿度很高时,能大大促进树干的呼吸作用. 相似文献
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落叶松人工林能否保持无机动态平衡、稳定生长,主要取决于每年还原于土壤中凋落物营养元素成分和数量。本研究目的在于揭示凋落物变化的各种规律,以及营养元素的潜在还原量。为改善林地条件,建立最佳结构模式的林分提供科学依据。为此我们对黑龙江省东部尚志县帽儿山兴安落叶松人工林四年凋落物营养元素进行了分析研究。结果表明: 1.落叶松树种的凋落物数量,包括叶、枝、皮等,四年平均每公顷干重量为3099.5kg,林内天然阔叶树为237.4kg,总计为3336.9kg。 2.不同种类凋落物营养元素的含量差异显著,叶含量最多,枝次之,皮中含量最小。 3.平均每年每公顷还原于林地的营养元素总量(N、P、K、Ca、Mg、Cu、Zn、Mn)为98.8697kg,其中落叶松叶为85.5998kg,阔叶树叶为8.385kg,落叶松落枝为2.0335kg,林内落叶松落皮为9.13kg,阔叶树枝为9.27kg。 相似文献
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The extractive content of lignin and the brown-rot decay-resistance against Coniophora puteana and Poria placenta were studied in larch heartwood from different species and origin (Larix decidua var. decidua, L. decidua var. sudetica, L. kaempferi , L. × eurolepis). The study material consisted of 106 trees from a 39-year old provenance trial in France. The hot-water-soluble extractives were very variable (from5.66% to 20.50% of dry weight), but there was no significant variation between the investigated species and origins. In contrast, acetone extractives, the total amount of phenolics and lignin showed significant differences. The concentration of phenolics and lignin was significantly higher in L. kaempferi and in L. × eurolepis than in L. decidua. The total phenolics content was strongly correlated with decay-resistance in all investigated larch origins. A higher concentration of phenolics goes hand in hand with higher decay resistance and phenolics might therefore be a promising parameter to rapidly evaluate the level of decay-resistance in larch. 相似文献
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煤矿露天开采行为导致矿区岩体剥离、植被破坏和土壤物理化学性质的巨大改变,对采矿区土壤生态系统造成剧烈扰动,使其成为水土流失、滑坡等矿区潜在生态风险的主要受体。以内蒙古平庄西露天煤矿区土壤生态系统为研究对象,通过分析矿区主要景观单元的土壤理化性质、植被演替规律与土壤线虫群落结构特征,研究其生态脆弱性分布与变化规律。结果表明矿区土壤系统的成熟度与稳定度与其形成年限具有相关性,但与农田生态系统和未受扰动的自然生态系统相比,煤矿开采区与排弃物堆放区的土壤结构较差、土壤肥力偏低、动、植物群落成熟度和稳定性较差。受土壤养分条件及土壤微生物数量等因素的限制,其植被自然恢复速度慢,生态系统脆弱,需通过土壤改良、合理选种适生植物、改善土壤养分条件,促进植被重建。 相似文献
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落叶松是我国北方重要的针叶树种,天然落叶松倒木上生长有种类繁多的多孔菌,它们能够分解倒木中的纤维素、半纤维素和木质素,促进森林生态系统的物质循环,同时维持生态系统中的碳平衡,在森林生态系统中发挥重要的生态功能.本文针对我国5种主要落叶松树种上的多孔菌种类,综合分析了该类群的物种组成和分布特征,并对不同树种上的多孔菌种群进行对比分析.结果表明: 落叶松上共有多孔菌107种,分属11科43属,其中褐腐真菌种类49种,占到总数的45.4%,是中国已报道褐腐真菌种类的50%.91.7%的多孔菌生长在刚开始腐烂的倒木上.兴安落叶松上的多孔菌不论是种类还是数量均比其他4种落叶松多.兴安落叶松和长白落叶松以及新疆落叶松和西藏落叶松上的多孔菌种群相似度高,这与其林分的天然分布相一致. 相似文献
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The environment has a strong influence on the abundance and distribution of plant pathogenic organisms and plays a major role in plant disease. Climatological factors may also alter the dynamics of the interactions between plant pathogens and their hosts. Nothophaeocryptopus (=Phaeocryptopus) gaeumannii, the causal agent of Swiss needle cast (SNC) of Douglas‐fir, is endemic to western North America where it exists as two sympatric, reproductively isolated lineages. The abundance of this fungus and the severity of SNC are strongly influenced by climate. We used statistical and population genetic analyses to examine relationships between environment, pathogen population structure, and SNC severity. Although N. gaeumannii Lineage 2 in western Oregon and Washington was most abundant where SNC symptoms were most severe, we did not detect a significant relationship between Lineage 2 and disease severity. Warmer winter temperatures were inversely correlated with foliage retention (AFR) and positively correlated with the relative abundance of Lineage 2 (PL2). However when distance inland, which was strongly correlated with both AFR and PL2, was included in the model, there was no significant relationship between Lineage 2 and AFR. Spring/early summer dew point temperatures also were positively associated with total N. gaeumannii abundance (colonization index (CI)) and inversely correlated with AFR. Warmer summer mean temperatures were associated with lower CI and higher AFR. Our results suggest that the two lineages have overlapping environmental optima, but slightly different tolerance ranges. Lineage 2 was absent from more inland sites where winters are colder and summers are warm and dry, while Lineage 1 occurred at most sites across an environmental gradient suggesting broader environmental tolerance. These relationships suggest that climate influences the abundance and distribution of this ecologically important plant pathogen and may have played a role in the evolutionary divergence of these two cryptic fungal lineages. 相似文献
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BRANDY J. SAFFELL FREDERICK C. MEINZER STEVEN L. VOELKER DAVID C. SHAW J. RENÉE BROOKS BARBARA LACHENBRUCH JENNIFER MCKAY 《Plant, cell & environment》2014,37(7):1536-1547
Swiss needle cast (SNC) is a fungal disease of Douglas‐fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree‐rings of Douglas‐fir and a non‐susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ13C) of treated Douglas‐fir tree‐rings was greater than that of untreated Douglas‐fir tree‐rings during the fungicide treatment period. Both annual growth and tree‐ring Δ13C increased with treatment such that treated Douglas‐fir had values similar to co‐occurring western hemlock during the treatment period. There was no difference in the tree‐ring oxygen stable isotope ratio between treated and untreated Douglas‐fir. Tree‐ring Δ13C of diseased Douglas‐fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years. 相似文献
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Wood area index (WAI; total surface area of branches and bole per unit of land area) is an important yet often neglected forest structural attribute. Branchwood surface area, in particular, has significant implications for many ecophysiological processes including total respiration and interception of radiation and rainfall. Branch surface area was estimated at the branch-, tree-, and stand-level for 33 Douglas-fir (Pseduotsuga menziesii [Mirb.] Franco) plantations in the Oregon Coast Range. Patterns in WAI, leaf area index (LAI; total surface area of needles per unit of land area), tree area index (TAI=WAI+LAI) and various ratios of these dimensions were then investigated. The main axes of primary branches (those attached to the main stem) comprised 82±13% of total branchwood surface area. Tree surface area (needles + woody tissue) increased with increasing tree size and crown length, and decreased with greater intensity of Swiss needle cast (SNC). At the stand-level, woody surface area increased with greater stand density and decreased with more severe SNC, but on average it constituted 29±12% of total tree surface area. Branchwood surface area and bole surface area contributed equally to WAI. The variation in WAI for a given LAI has important implications for radiation and rainfall attenuation in these stands and for accurate partitioning of intercepted radiation between photosynthetic and non-photosynthetic tissues. 相似文献