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1.
基于楠木(Phoebe zhennan)人工林5块同定标准地25株枝解析数据,进行楠木人工林树冠体积与叶面积指数预估模型研究,研究结果表明:楠木人工林树冠体积和叶面积指数随着林木胸径、树高、冠幅和冠高的增大而增大;在分析树冠体积和叶面积指数与林木变量的基础上,利用SPSS统计软件建立了树冠体积(V)和叶面积指数(LAI)的预估模型:所建立的楠木人工林树冠体积的预估模型为:V=0.2750L2.253H10.770(L为冠幅,m;H1为冠高,m),叶面积指数的预估模型为:LAI=0.7845+0.5481H1-0.0288H12+0.0007H13;对预估模型进行检验,结果表明,两个模型的预估精度均大于88%,说明所建模型可以较好地预估楠木人工林树冠体积和叶面积指数. 相似文献
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广西桉树人工林物种多样性与生物量关系 总被引：7，自引：0，他引：7
对广西东门桉树人工林18个试验小区物种多样性、群落总生物量、乔木层生物量和林下植被生物量进行研究.结果表明:1)桉树人工林物种丰富度与乔木层、灌草层和群落总生物量呈极显著正相关(α=0.001),相关系数分别为0.693 5、0.702 8和0.710 6;2)叶面积指数与物种丰富度和林下植被生物量均表现为极显著正相关(α=0.001),相关系数分别为0.731 0和0.685 6;3)乔木层生物量与土壤有机质、土壤水解N以及物种丰富度与土壤有机质有较强的相关性.相关系数分别为0.641 6、0.620 3和0.635 9,在0.1水平上达到显著;林下植被生物量与9种土壤养分的相关性均较小,相关系数在0.4以下.以上结果表明:桉树人工林物种多样性的增加有利于林分生物量的提高;叶面积指数和土壤有机质在小尺度上的变化对桉树人工林的物种丰富度和生物量影响较大. 相似文献
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基于冠层分区的辽东山区长白落叶松叶面积模拟研究 总被引：1，自引：0，他引：1
《内蒙古林业调查设计》2017,(3):92-97
文章以辽东山区长白落叶松林(Larix olgensis)为研究对象,通过调查树冠及枝条解析因子、实测叶面积,构建基于最优冠层分区形式的枝条叶面积模型,结果表明:基径(BD)是枝条叶面积(BLA)的最佳解释变量,相对冠层深度(H)0.67是模拟效果最优的冠层分区界限,树冠上层枝条叶面积最优模型为CAR模型:BLA=0.006BD1.746,决定系数(R2)为0.796,预估精度(P)达到90.61%;下层枝条叶面积最优模型为二次曲线:BLA=0.009BD2-0.476BD+7.186,决定系数(R2)为0.709,预估精度(P)达到80.65%。 相似文献
4.
通过对华中神农架海拔1500米至2600米之间11个箭竹样方的研究，阐述了箭竹群落物种丰富度，物种多样性，物种均匀性，生活型谱及群落类型的海拔变化。从最低样方(1680米)到最高样地(2570米)，微管束植物从30种降为7种，服从线性模型：Y=55.99-1.83X(R2=0.84，P<0.001)；物种多样性从3.18降为1.78，服从线性模型：Y=4.67-0.10X (R2=0.72，P=0.001；物种均匀度在0.83至0.99之间变化，但与海拔并不相关。在生活型谱中，一年生植物，地下芽植物和大高位芽树木的百分比随海拔升高而升高；灌木和中高位芽树木随海拔升高而降低；多年生草本和半灌木与海拔关系不大。箭竹群落可分为5种类型：常绿阔叶林下，落叶阔叶林下，温性针叶林下，寒温性针叶林与混交林下，纯箭竹林。 相似文献
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【目的】精确估测银杏人工林有效叶面积指数(eLAI),以更好了解银杏人工林的生长和竞争、理解人工林生态系统的功能和生产力。【方法】基于多旋翼无人机激光雷达(LiDAR)系统获取的点云数据,结合45块地面实测样地数据,使用孔隙度模型法(通过计算点云的冠层穿透率,根据Beer-Lambert定律计算有效叶面积指数)和统计模型法(首先通过地面实测的有效叶面积指数和所提取的LiDAR特征变量建模,然后借助拟合的模型估测有效叶面积指数)对我国典型银杏人工林进行样地尺度的有效叶面积指数估测。【结果】1)使用统计模型法估测eLAI时,仅利用LiDAR高度特征变量估测精度为R2=0. 38(rRMSE=54%),引入其他特征变量(冠层密度特征、冠层容积比以及强度特征变量)后精度分别达到R2=0. 64(rRMSE=26%)、R2=0. 61(rRMSE=28%)、R2=0. 74(rRMSE=23%); 2)根据Cover将样地分组建模后发现,分组建模的精度优于不分组建模的精度;3)孔隙度模型法估测有效叶面积指数的精度为R2=0. 71(rRMSE=32. 0%)。【结论】结合多组LiDAR特征变量估测有效叶面积指数能够充分挖掘LiDAR数据包含的冠层结构特性,从而提升估测精度;同时,使用孔隙度模型法可以有效估测银杏人工林有效叶面积指数。无人机LiDAR点云在估测银杏人工林有效叶面积指数上具有较好的潜力。 相似文献
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[目的]以吉林省汪清林业局金沟岭林场40株10～40年生长白落叶松的健康针叶为研究对象,建立叶面积回归模型并估计其比叶面积。[方法]通过WinSEEDLE种子和针叶图像分析系统获取长白落叶松50束共150针的针叶面积、长度、宽度以及周长,再分别烘干至恒质量获得叶片干质量。建立以叶长L、叶宽W、叶周长P和叶片干质量X为自变量,叶面积LA为因变量的一元、二元和三元线性、指数和幂函数回归模型,并用平均误差、总体相对误差、平均系统误差、平均预估误差和均方根误差等统计量来评价模型误差和拟合优度。采用算术平均法、比估计法和最小二乘法计算比叶面积,并对3种方法的方差进行比较,获取最优估算值。[结果]一元、二元和三元模型均以指数函数最佳,模型分别为LA=5.929 e~(1.313W)(R~2=0.858),LA=6.194 e~((0.023L+0.637W))(R~2=0.936)和LA=6.445 e~((0.021L+0.598W+18.067X))(R~2=0.941)。[结论]算术平均法获取的比叶面积的精度最高,该方法得到的长白落叶松的比叶面积为8.026 m~2·kg~(-1)。 相似文献
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叶面积和比叶面积是植物生长过程中的重要参数.本研究基于河北木兰围场实测油松数据,通过winSEEDLE种子和针叶图像分析系统获得油松522个单个针叶的表面积LA、针叶长度L、针叶宽W、针叶周长P,分别建立了以针叶长、针叶宽、针叶周长等形状属性为自变量的叶面积估计模型和以针叶干质量为自变量的叶面积估计模型.用总相对误差、平均相对误差、平均相对误差绝对值、均方根误差、预估精度5个统计量来检验模型的误差和拟合优度,经检验模型LA=-2.761 +0.464 L +6.608W和LA =1.345 +0.501X分别为这两种模型中最好,X为针叶干质量.通过对算术平均法、比估计法、最小二乘法3种方法的比较,得到油松的比叶面积为7.08 m2 ·kg-1.本研究为油松叶面积的估计提供了一个简单可靠的方法. 相似文献
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2005-2006年夏季在河北塞罕坝地区运用固定样线法对退化森林生态系统人工针叶林恢复形成的40年生人工针叶林鸟类群落进行调查,并同自然恢复形成的天然落叶阔叶林和天然针阔混交林进行比较.共记录鸟类39种.分别隶属于8目17科.结果表明:人工针叶林恢复对退化森林生态系统鸟类群落具有重要影响;人工针叶林鸟类物种数为(4.14±0.60)种·hm-2,密度为(26.21±7.64)只·hm-2,均高于或显著高于(P=0.018)天然阔叶林,且密度与天然混交林无显著差异(P=0.902),人工针叶林中的沼泽山雀和黄眉柳莺的密度有了显著提高,分别从(2.78±0.67)只·hm-2和(1.21±0.45)只·hm-2增加到(13.57±5.58)只·hm.(P=0.027)和(5.95 4-1.56)只·hm-2(P=0.009,0.002),但人工针叶林鸟类群落物种多样性值(H')较小(0.98 4-0.10)、均匀度(J)显著较低(0.73 ±0.04)(P=0.003,0.045);在鸟类4个取食集团中,人工针叶林有2个取食集团的物种组成与自然恢复无显著差异,但密度却有较大的变化,人工针叶林可以显著提高食虫鸟的密度(P=0.041),但杂食鸟和食谷鸟密度均显著低于天然混交林(P=0.007,0.002). 相似文献
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2008年4月—2021年12月，在四川申果庄自然保护区内及周边区域布设了102个相机监测位点，累计25 588个有效相机工作日，共获得独立有效记录4 705次，识别出野生兽类5目15科20种，野生鸟类4目11科40种，包括2种国家I级和15种国家II级重点保护野生动物；IUCN红色名录濒危（EN）物种2种，易危（VU）物种6种，近危（NT）物种2种。血雉（Ithaginis cruentus）(RAI=2.149)、小熊猫（Ailurus fulgens）(RAI=1.622)、红腹角雉（Tragopan temminckii）(RAI=1.614)、毛冠鹿（Elaphodus cephalophus）(RAI=1.501)和白腹锦鸡（Chrysolophus amherstiae）(RAI=1.450)的相对多度位于鸟兽前5位；小熊猫（SO=63.73%）、野猪（Sus scrofa）(SO=47.06%)、毛冠鹿（SO=43.14%）、豹猫（Prionailurus bengalensis）(SO=42.16%)和血雉（SO=41.18%）的位点占有率位于鸟兽前5位。活动节律分析... 相似文献
10.
《中南林业科技大学学报(自然科学版)》2016,(10)
本研究基于辽东山区实测落叶松特征因子,通过枝条解析法获得了254组枝条的叶面积、枝条基径、枝条长度等属性数据,在枝条水平上采用一元非线性方程和二元及多元非线性方程建立以枝条属性因子为自变量的枝条叶面积模型。结果表明:枝条基部断面积(d2)与枝条叶面积有最高的相关性,最优一元枝条叶面积模型为:y=8.967/(1+50.901e-0.084d),其R2达到0.719,测算精度为86.34%(α=0.05)。引入相对着枝深度(RDINC),使得二元及多元模型的决定系数显著提高,最优二元枝条叶面积模型为:y=0.002(d2)2.260e-1.701RDINC,其R2达到0.796,测算精度为88.57%(α=0.05)。 相似文献
11.
华中神农架箭竹(Fargesia spathacea)群落之海拔多样性(英文) 总被引：5，自引：0，他引：5
通过对华中神农架海拔1500米至2600米之间11个箭竹样方的研究,阐述了箭竹群落物种丰富度,物种多样性,物种均匀性,生活型谱及群落类型的海拔变化。从最低样方(1680米)到最高样地(2570米),微管束植物从30种降为7种,服从线性模型:Y=55.991.83X(R2=0.84,P<0.001);物种多样性从3.18降为1.78,服从线性模型:Y=4.670.10X (R2=0.72,P=0.001;物种均匀度在0.83至0.99之间变化,但与海拔并不相关。在生活型谱中,一年生植物,地下芽植物和大高位芽树木的百分比随海拔升高而升高;灌木和中高位芽树木随海拔升高而降低;多年生草本和半灌木与海拔关系不大。箭竹群落可分为5种类型:常绿阔叶林下,落叶阔叶林下,温性针叶林下,寒温性针叶林与混交林下,纯箭竹林。图4表2参19。 相似文献
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The stable oxygen isotope ratio (delta(18)O) of tree-ring cellulose is jointly determined by the delta(18)O of xylem water, the delta(18)O of atmospheric water vapor, the humidity of the atmosphere and perhaps by species-specific differences in leaf structure and function. Atmospheric humidity and the delta(18)O of water vapor vary seasonally and annually, but if the canopy atmosphere is well mixed, atmospheric characteristics should be uniform among co-occurring trees. In contrast, xylem water delta(18)O is determined by the delta(18)O of water being drawn from the soil, which varies with depth. If co-occurring trees draw water from different soil depths, this soil-water delta(18)O signal would be manifest as differences in delta(18)O among the trees. We examined the variation in tree ring delta(18)O, over eight decades during the 20th Century, among three species co-occurring in natural forest stands of the northern Rocky Mountains in the USA. We sampled 10 Douglas-firs (Pseudotsuga menziesii (Mirb.) Franco var. glauca), 10 ponderosa pines (Pinus ponderosa Laws.) and seven western white pines (Pinus monticola Dougl.). As expected, variation in atmospheric conditions was recorded in the delta(18)O of the cellulose produced in a given year, but observed climatic correlations with delta(18)O were weak. Significant correlations with June climate data included: daily maximum temperature (r = 0.29), daily minimum temperature (r = -0.25), mean temperature (r = 0.20), mean daily precipitation (r = -0.54), vapor pressure deficit (r = 0.32) and solar radiation (r = 0.44). Lagged effects were observed in Douglas-fir and western white pine. In these species, the delta(18)O of a given annual ring was correlated with the delta(18)O of the previous ring. Ponderosa pine showed no significant autocorrelation. Although the species means were correlated among years (r = 0.67 to 0.76), ponderosa pine was consistently enriched in delta(18)O relative to the other species; differences were close to 2 per thousand and they are steadily increasing. Relative to the mean for the three species, ponderosa pine is becoming steadily more enriched (-1.0 per thousand). In contrast, Douglas-fir is being steadily depleted and western pine is intermediate, with an enrichment of 0.5 per thousand. Because all trees were exposed to the same atmospheric conditions, the differences in delta(18)O observed between species are likely due either to differences in the depth of water extraction or leaf function. If the former, presumably ponderosa pine has steadily taken up more water from near the soil surface and Douglas-fir has shifted uptake to a greater depth. If the latter, we suggest the pronounced changes in leaf-water delta(18)O are a result of changes in leaf structure and function with tree size and age. 相似文献
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We used chlorophyll fluorescence to examine photosynthetic responses to excess Mn accumulation in leaves of four tree species differing in successional traits. Betula ermanii Cham. (Be) and Alnus hirsuta Turcz. (Ah) were studied as representatives of early-successional species. Ulmus davidiana Planch. var. japonica (Rehder) Nakai (Ud) was selected as a mid-successional species, and Acer mono Maxim. var. glabrum (Lév. et Van't.) Hara (Am) was chosen as a late-successional species. In Be, Ah and Am, high foliar concentrations of Mn had little effect on maximum photochemical efficiency of photosystem II (PSII), as indicated by the values of dark-adapted F(v)/F(m), whereas a significant decrease was observed in Ud. Photochemical quenching (qP) and the excitation capture efficiency of open PSII (F'(v)/F'(m)) decreased with increasing leaf Mn concentration at photosynthetic steady state after a 15-min exposure to 430 &mgr;mol m(-2) s(-1) PPFD. Compared with early-successional species, these decreases were greater in mid- and late-successional species leading to lower effective quantum efficiencies of PSII (DeltaF/F'(m) = qP x F'(v)/F'(m) = (F'(m) - F)/F'(m)). To determine the extent of photoinhibition, F(v)/F(m) of the illuminated leaves was remeasured after a 15-min dark period. Compared with the dark-adapted F(v)/F(m), we observed a significant decrease in F(v)/F(m) in Am leaves containing high concentrations of Mn. These chlorophyll fluorescence studies indicate that the early-successional species Be and Ah have a higher tolerance to excessive accumulations of Mn in leaves than the mid- and late-successional species Ud and Am. 相似文献
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Many bottomland tree species are tolerant of compacted soil and perform well in urban environments; however, the mechanism underlying this tolerance is unknown. Increased soil water content has been shown to alleviate some of the effects of soil compaction on plant growth, presumably because increasing soil water reduces soil strength. We hypothesized that tree species tolerant of very wet soils would have opportunities for root growth in compacted soil when high soil water contents reduced soil strength, whereas species intolerant of bottomland conditions would not. We tested this hypothesis on flowering dogwood (Cornus florida L.), a mesic species intolerant of inundation, and silver maple (Acer saccharinum L.), a bottomland species. Seedlings of both species were grown in pots for 21 and 30 days, respectively, in a growth chamber in native loam soil maintained at various combinations of soil strength and soil water tension. Downward root growth rate decreased in response to increasing soil strength in both species. At low soil strength (0.6 MPa), downward root growth rate of dogwood seedlings slowed when soil was either excessively wet or dry, whereas root growth rate of silver maple seedlings increased linearly with soil water content. In moderately compacted soil (1.5 g cm(-3) bulk density), silver maple seedlings had greater root growth rate, root length per plant, and ratio of root length to root dry weight in wet soil (0.006 MPa soil water tension) than in moist and dry soils (0.026 and 0.06 MPa, respectively), even though mean oxygen diffusion rate (ODR) was only 0.28 &mgr;g cm(-2) (SE = 0.05). No such effect was detected in highly compacted soil (1.7 g cm(-3) bulk density) in either species. Mean ODR showed a weak positive correlation with soil water tension (r = 0.40, P = 0.07), but was unrelated to soil strength. We conclude that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity. 相似文献
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In tropical moist forests, seasonal drought limits plant survival, productivity and diversity. Drought-tolerance mechanisms of tropical species should reflect the maximum seasonal water deficits experienced in a particular habitat. We investigated stem xylem vulnerability to cavitation in nine tropical species with different life histories and habitat associations. Stem xylem vulnerability was scored as the xylem water potential causing 50 and 75% loss of hydraulic conductivity (P50 and P75, respectively). Four shade-tolerant shrubs ranged from moderately resistant (P50=-1.9 MPa for Ouratea lucens Kunth. Engl.) to highly resistant to cavitation (P50=-4.1 MPa for Psychotria horizontalis Sw.), with shallow-rooted species being the most resistant. Among the tree species, those characteristic of waterlogged soils, Carapa guianensis Aubl., Prioria copaifera Griseb. and Ficus citrifolia Mill., were the most vulnerable to cavitation (P50=-0.8 to -1.6 MPa). The wet-season, deciduous tree, Cordia alliodora (Ruiz and Pav.) Oken., had resistant xylem (P50=-3.2 MPa), whereas the dry-season, deciduous tree, Bursera simaruba (L.) Sarg. was among the most vulnerable to cavitation (P50=-0.8 MPa) of the species studied. For eight out of the nine study species, previously reported minimum seasonal leaf water potentials measured in the field during periods of drought correlated with our P50 and P75 values. Rooting depth, deciduousness, soil type and growth habit might also contribute to desiccation tolerance. Our results support the functional dependence of drought tolerance on xylem resistance to cavitation. 相似文献
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复合经营模式对土壤酶活性的影响 总被引：1，自引：0，他引：1
采样分析不同耕作模式的土壤酶活性和肥力因子,结果表明:所有模式的土壤过氧化氢酶、脲酶、蔗糖酶、多酚氧化酶的季节变化趋势一致,复合经营模式的土壤肥力和酶活性高于单种作物土壤。将土壤酶活性和土壤肥力因子进行相关分析,结果表明:蔗糖酶活性与有机质(r=0.558 7)含量极显著正相关;过氧化氢酶活性与全钾(r=0.524 7)和水解性氮(r=0.442 5)含量极显著正相关;多酚氧化酶活性与有机质(r=-0.577 9)、全氮(r=-0.619 7)和全磷(r=-0.638 5)含量均极显著负相关;脲酶活性与有机质(r=0.908 5)、速效钾(r=0.900 6)、全氮(r=0.843 5)、水解性氮(r=0.796 5)、速效磷(r=0.763 0)和全钾(r=0.676 4)含量均达到极显著正相关水平。 相似文献
19.
Spatial pattern dynamics among co-dominant populations in early secondary forests in Southwest China
《林业研究》2021,(4)
The canopy of subtropical natural forests usually consists of several co-dominant populations(CDPs),which play a crucial role in forest structure,formation of the forest environment,and ecological function.However,little attention has been given to changes in spatial patterns in CDPs during natural succession.Cyclobalanopsis glauca(Thunb.)Oerst.,Quercus variabilis Blume,and Pinus yunnanensis var.tenuifolia W.C.Cheng Y.W.Law are canopy species that form CDPs in zonal forests along the Nanpan River in southwest China.We used the g(r) function and its bivariate distribution model,g_(12)(r),which is based on distances between pairs of points,to explore the dynamics of the three CDP species with respect to distribution patterns and spatial correlations in two secondary forests(one 30-year-old forest [30-YF] and one 57-year-old forest [57-YF]).The following key results were obtained:(1) there was a clumped pattern in the 30-YF,but the intensity of aggregation varied among populations and life stages.The distribution pattern gradually shifted to become random with longer succes sion time(i.e.,30-YF vs.57-YF),expansion of the observation scale(r=0-20 m),and at later life stages.(2) Aside from the mid-sized C.glauca trees and large P.yunnanensis trees,the trees repulsed each other at certain scales(r=0-2,5-6,11-12,14-16 m) in the 30-YF.Almost all of the life stages in the CDPs were independently correlated.This independent correlation was exacerbated by a longer succession time.(3) An increase in life stages and longer succession also promoted independent changes in intraspecific correlations.(4) Intraspecific correlations were stronger than interspecific correlations.Our results showed that reducing exclusive competition is essential to coexistence in CDPs.Inter-and intra-specific repulsion may occur at the same time,but intraspecific repulsion was the main driving force behind the random distributions and independent correlations. 相似文献
20.
Forest process models predict ecosystem responses from climate variables and physiological parameters. The parameters describe key ecosystem attributes, often as lumped averages. However, the sources and magnitude of variation in these physiological parameters are unknown, which complicates sampling if models are to be parameterized with field measurements. We measured several key parameters, which had been identified by sensitivity analyses of three models, in Abies grandis (Dougl.) Lindl. and Pseudotsuga menziesii var. glauca (Beissn.) Franco trees throughout the growing season. Trees were sampled at eight sites across the interior northwest of the USA. At each site, fertilized and control plots were sampled. The design provided statistical replication for the analysis of variance within a site, allowing us to draw inferences about a regional population of stands. Specific leaf area (SLA) varied by canopy position and treatment (P = 0.0003), by date of sampling (P < 0.0001) and by species (P = 0.0188). Mass-based foliar nitrogen concentration (%N) increased during the summer in both species (P = 0.0019), but at a faster rate in P. menziesii var. glauca than in A. grandis. Sun foliage had a higher mean %N (1.00, SE = 0.02%) than shade foliage (0.92 +/- 0.01%). Apparent quantum yield (Phi) varied among treatments, between species and between canopy positions; each of these variables interacted with date of sampling (P = 0.0207, P < 0.0001 and P = 0.0344, respectively). In A. grandis, mean Phi values (+/- SE) were 0.048 +/- 0.006 mol CO2 (mol incident photon)-1 for sun foliage and 0.067 +/- 0.007 mol CO2 (mol incident photon)(-1) for shade foliage. In P. menziesii, the corresponding mean Phi values were 0.032 +/- 0.003 and 0.047 +/- 0.004 mol CO2 (mol incident photon)-1. Parameters SLA, %N and Phi were all influenced by date, fertilizer treatment, species and crown position. We discuss methods of inferring quantum yields from light response curves and their utility for parameterizing process models. Parameter mean values are presented for each site; these tables provide a documented data set for the parameterization of models describing the western interior forests of the USA. 相似文献