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1.
通过野外调查与室内分析相结合,应用主成分分析法,从衡量土壤抗蚀性的16个指标中,优化得到赣县稀土采矿区巨桉林地土壤抗蚀性7个最佳评价指标：分散系数（X1）、团聚度（X2）、>0.25 mm水稳性团聚体含量（X3）、>0.5 mm水稳性团聚体含量（X4）、<0.05 mm粉黏粒含量（X5）、>0.25 mm团聚体破坏率（X6）和<0.001 mm黏粒含量（X7）,并以此为变量分析比较不同林龄巨桉林地土壤抗蚀性变化规律。结果表明：不同林龄巨桉林地土壤抗蚀性综合指数大小为：1年生林地>2年生林地>4年生萌芽1 a林地>裸露地。在此基础上,以上述7个评价指标为自变量,以土壤抗蚀性综合指数（Y）为因变量,进行回归分析,得出稀土采矿区土壤抗蚀性综合评价方程为：Y=0.309 X1+0.038 X2 -0.161 X3 -0.643 X4 +0.491 X5 -0.032 8 X6 +0.129 X7 +41.637,因子决定系数R2=0.991 5,F=49.84,各因子间显著相关,方程拟合较好,可为构建稀土采矿区土壤抗蚀性评价指标体系提供依据。 相似文献
2.
[目的]以BCI 50 hm2大样地为研究对象,利用空间结构参数一元分布和二元分布,量化评价BCI 50 hm2大样地活立木整体、冠层和下层的空间结构特征。[方法]以巴拿马BCI 50 hm2森林大样地（2010年第7次调查）中所有胸径（DBH）≥ 1 cm的活立木数据为材料,采用基于相邻木关系的空间结构参数方法对其整体、冠层和下层活立木的空间结构进行分析。[结果]表明：BCI大样地第7次调查整体活立木的平均角尺度（W）为0.504,样地大部分林木处于极强度混交状态（Mi=1）,比例为74.7%。样地的冠层和下层的状态与整体林分的状态相同,均处于随机分布、强度混交和中庸偏劣势的状态。冠层中几乎没有林木个体处于零度混交（Mi=0）状态。下层的大部分林木处于中高度大小比数和中高度混交度等级的组合上。样地中大部分活立木为小径级个体（1 cm ≤ DBH < 20 cm）,使得样地中大部分林木处于劣势状态。无论在整体、冠层和下层,活立木的混交度（Mi）都处于极高水平,在参照树周围的最近4株相邻木中同种个体的比例（Mi=0.00,Mi=0.25）极低。[结论] BCI大样地整体、冠层和下层活立木空间结构呈随机分布,林木的混交度极高,样地中同种个体在最近4株邻体这样的小尺度上呈现聚集分布的情况几乎不存在。 相似文献
3.
对闽南地区麻竹人工林地上部分生物量模型及现存生物量结构进行了研究。结果表明:以模型m=a·(D2H)b对麻竹地上部分总生物量和秆生物量进行估计较为可靠,而对枝、叶生物量的估计需引进枝下高因子h及模型m=a·Db·(H-h)C或m=a·Db·[(H-h)/h]C.闽南地区麻竹人工林地上部分平均现存生物量为39.518t·hm-2,按年龄分配为:3年生生物量最高,占59.17%,其次为2年生、4年生、5年生;按器官分配为:秆生物量最高,占62.81%,其次为枝、叶。地上部分总生物量与秆生物量随竹秆高度增加而递减,枝、叶生物量自6～8m区分段分别向秆基及秆梢递减。 相似文献
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[目的]研究森林沼泽演替与火干扰条件下土壤微生物结构与多样性变化,为进一步揭示土壤微生物群落在森林沼泽保护与恢复中的作用提供依据。[方法]采用磷脂脂肪酸法与BIOLOG方法,研究大兴安岭南瓮河国家自然保护区内主要森林沼泽类型(兴安落叶松-狭叶杜香-藓类沼泽、兴安落叶松-兴安杜鹃-藓类沼泽、兴安落叶松+白桦-苔草沼泽)与2006年受不同火强度干扰沼泽(重度火烧的兴安落叶松-兴安杜鹃-藓类沼泽和中度火烧的兴安落叶松+白桦-苔草沼泽)土壤微生物群落特征,探讨沼泽主要发育阶段与火干扰强度对土壤微生物群落的影响。[结果]研究区域土壤微生物群落以16:00(16.29±5.62 nmol·g-1)、甲烷氧化菌(18:1ω8t)(9.89±8.61 nmol·g-1)与16:1ω7c(9.79±3.24 nmol·g-1)的微生物为优势种群。土壤微生物总PLFAs含量、革兰氏阳性菌(G+)中a15:0、i16:0、i17:0、革兰氏阴性菌(G-)中的cy19:0、真菌中的18:2ω6c、甲烷氧化菌(18:1ω8t)与森林沼泽发育阶段、火干扰明显相关(p<0.05)。一般饱和直链脂肪酸/单烯饱和脂肪酸比(Sat/Mon)偏低,其比值随沼泽发育呈现增加趋势,受到火干扰后明显增加(p<0.05);真菌/细菌比(F/B)与革兰氏阳性菌/革兰氏阴性菌(G+/G-)未随着沼泽发育呈现出规律性变化,其比值受火干扰后明显发生改变(p<0.05)。土壤细菌与真菌对6类碳源的利用能力明显不同(p<0.001),其中土壤细菌对α-D-Lactose与L-Threonine利用存在差异性(Fα-D-Lactose =2.87 p=0.080,FL-Threonine=3.00 p=0.078),土壤真菌对D-Mannitol、D-glucosaminic Acid利用存在差异性(FTween 80=2.75,p=0.088, FD-Mannitol=3.53 p=0.047, FD-glucosaminic Acid=4.67 p=0.022),但沼泽类型与火干扰未对土壤微生物功能多样性产生影响(p>0.05)。[结论]土壤微生物量与沼泽发育阶段相关;沼泽发育与火干扰改变土壤微生物群落结构。土壤细菌与真菌对碳源利用方面具有选择性。 相似文献
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利用相对生长方程与碳/氮分析法,对比分析长白山天然白桦林在7个立地类型(阳坡上、中、下部与阴坡上、中、下部及谷地)上的生态系统碳储量(植被与土壤)、净初级生产力与年净固碳量,揭示立地类型对温带白桦林生态系统碳库与固碳能力的影响规律。结果表明:①长白山天然白桦林植被碳储量(45.61 87.22 t·hm-2)呈阴坡上、中部与谷地>阳坡上、中部与阴坡下部>阳坡下部变化趋势,且高立地型显著高于低立地型50.8% 91.2%(P<0.05),中立地型高于低立地型20.4% 44.4%(P>0.05);②土壤碳储量(66.71 158.51 t·hm-2)呈阳坡上部、阴坡中部与谷地>阳坡中、下部与阴坡下部>阴坡上部变化趋势,且高立地型显著高于低立地型99.3% 137.6%(P<0.05),中立地型高于低立地型40.7% 67.0%(P>0.05);③生态系统碳储量(139.44 231.12 t·hm-2),呈阴坡中部与谷地>阳坡上部与阴坡下部>阳坡中、下部与阴坡上部变化趋势,且高立地型显著高于低立地型35.6% 65.7%(P<0.05),中立地型高于低立地型5.8% 34.7%(P>0.05);④植被净初级生产力(4.92 11.25 t·hm-2·a-1)和年净固碳量(2.32 5.32 t·hm-2·a-1)均呈阴坡上、中部>阳坡上、下部与阴坡下部及谷地>阳坡中部变化趋势,且高立地型显著高于中、低立地型42.5% 128.7%和45.2% 129.3%(P<0.05),中立地型高于低立地型10.6% 56.3%和14.2% 53.4%,但仅阴坡下部提高显著。因此,长白山白桦林生态系统碳库与固碳能力均受到立地类型的强烈影响,故对其碳汇功能评价应考虑其立地分异规律性。 相似文献
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为研究巨尾桉人工林林木根径、胸径与树高数学模型,在滇西南的双江县选取138株（其中建模样本103株,检验样本35株）树干健全、通直圆满、无分杈的巨尾桉人工林样木,采集其根径与树高、胸径与树高成对数据。利用SPSS 21.0回归分析,分别建立线性方程、对数曲线、指数曲线和Logistic曲线等11个数学模型,以决定系数（R2）、估计值的标准误（SEE）、均方差（RMSE）、平均绝对偏差(MAD)、相对误差（RS）、模型预估精度（P）、显著性(Sig)P值作为模型评价指标,对比11个模型的拟合效果。结果表明,11个根径—树高模型显著性（Sig）P<0.001,其中有9个模型的预估精度大于97%,回归方程达到极显著水平,拟合效果较好;11个胸径—树高模型显著性（Sig）P<0.001,其中9个模型的预估精度大于97%,回归方程达到极显著水平,拟合效果也较好。通过对各项评价指标进行比较分析,确定三次项曲线H=a0+a1DR+a2DR2+a3DR3是拟合效果最好的根径—树高数学模型,代入拟合参数后的根径—树高数学模型表达式为H=11.069901-0.729389DR+0.096782DR2-0.001984DR3;线性方程H=a0+a1D是拟合效果最好的胸径—树高数学模型,代入拟合参数的胸径—树高数学模型表达式为H=4.818702+0.891217D。 相似文献
7.
以胶合板材为培育目标,研究了I-69杨胶合板用材林平均单株材积与造林密度和优势高的关系。分别不同林龄(6～11a)建立了平均单株材积与造林密度及优势高的模型V=a0Na1 H0a2,通过生产弹性分析、边际产量分析,研究了密度效应及优势高效应,计算出了不同林龄林分的生产弹性值和边际产量,并且根据立地及密度效应模型研究了造林密度、林龄、立地指数对林分蓄积的影响。认为在长江中、下游地区营造I-69杨胶合板用材林密度应适当减小,选择造林地时以立地指数大于等于20m林地为佳。 相似文献
8.
应用相对生长法和典型样方调查法对华北沙地不同密度、不同年龄的小黑杨人工林生物量和生产力进行了估算,同时对树冠与生物量的关系进行了研究。结果表明:密度为1 000株· hm-2、500株· hm-2、250株· hm-2的小黑杨林分(27年生)的生物量分别为85.31 t·hm-2、102.60 t·hm-2、86.74 t·hm-2;生产力分别为3.16 t·hm-2·a-1、3.80 t·hm-2·a-1、3.21 t·hm-2·a-1,密度500株· hm-2为华北沙地小黑杨的合理密度。不同密度小黑杨不同器官生物量所占的比例差异不明显,地上部分生物量在83% - 86%之间,其中干57% - 62%,枝11% - 16%,叶2% - 3%,皮8% - 10%;地下部分生物量在14% - 17%之间。对不同年龄小黑杨的生物量和生产力研究表明,27年生的比23年生的分别高59.74%和36.20%。同时,23年生小黑杨的根、叶所占比例明显高于27年生的根、叶比例,但是干生物量所占比例低于27年生小黑杨,反映了23年生小黑杨的生物量和生产力处在快速生长期,小黑杨的轮伐期应在27年以后。小黑杨生物量与树冠之间存在极显著的相关关系,其中树干生物量与树冠指数之间可以用线性模型y=ax+b描述,利用遥感技术可以反映小黑杨林树干生物量,为进一步利用遥感预测小黑杨木材材性提供了重要的基础数据。 相似文献
9.
以位于浙江清凉峰国家级自然保护区1 hm2永久样地为研究材料,逐一测量并记录了样地中所有胸径≥1 cm树木的胸围,并对其挂牌标记、鉴定种名和确定坐标位置,分析了样地内木荷种群结构与空间格局。研究结果表明,DBH≤17.5 cm的木荷个体数量占80.5%,DBH>27.5 cm的仅占8.4%,种群能够实现自我更新,属稳定型种群。基于种群径级结构分析,木荷种群密度随个体胸径的变化趋势类似于偏正态分布形曲线。木荷在整个样地中的分布表现出明显的空间异质性,多数聚集于坡面和山脊的生境中。种群空间关联性分析表明,木荷大径级(DBH≥16.1 cm)和小径级(1 cm≤DBH＜16.1 cm)间在0-8 m的尺度上负相关,8-25 m的尺度上无关联。另外,25个小样地的木荷重要值为0-34.35%,平均重要值为8.24%,小样地间的这种巨大差异归因于木荷种群空间分布的聚集性。 相似文献
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角蜡蚧是雪松等园林树木的重要害虫之一,产卵多、繁殖强、危害重,准确测报其发生量与若虫孵化期,是防治成败的关键。通过1997年5月对产卵末期雌虫体质量、体长及产卵量的测定与室内变温、恒温饲养研究,其平均虫体质量x1=0.1103±0.0849g,体长x2=7.027±0.202mm,产卵量(y1)=4880.5±4440.53粒;产卵量与虫体质量、体长相关方程式分别为:y1=-571.25+50078.3x1,r1=0.9719>r0.01=0.496;y2=-10356.46+1983.39x2,r2=0.8436>r0.01=0.496.卵发育起点温度:C=10.25±1.53℃或C=9.94±0.19℃;有效积温K=165.15±6.96DD或K=141.51±2.15DD.经应用及检验与实际符合。 相似文献
11.
[目的]土壤密度是最基本的森林土壤水文物理性质参数,为了定量描述土壤密度随坡位的变化和影响因素,研究不同坡面土壤密度的空间异质性。[方法]在宁夏六盘山半湿润区香水河小流域,选择华北落叶松人工林和天然灌丛2个典型坡面,按坡位从上到下设置连续样地。2014年进行了森林土壤调查,在样地内掘土壤剖面,采用环刀法,分层测定土壤密度。[结果]在1 m深土层内,土壤密度(Y,g.cm-3)随土层(X,cm)加深呈线性增大,拟合关系式:华北落叶松坡面为Y1=0.755 5+0.007 7X(R2=0.99),天然灌丛坡面为Y2=0.919 5+0.004 7X(R2=0.98),其原因包括植被根系活动、土壤生物活动、砾石含量等的土层差异;在2个坡面上,0 100 cm土层平均土壤密度均有明显坡位差异,且2个坡面的沿坡整体变化趋势不相同,华北落叶松坡面从坡顶到坡脚是先逐渐增大,后趋于稳定;天然灌丛坡面从坡顶到坡脚是"增大-减小-增大"的趋势,不同土层土壤密度的坡面变化也各不相同。在华北落叶松林坡面引起土壤密度坡位差异的主要原因是海拔,而在天然灌丛坡面是植物生长状况;2个坡面的土壤密度平均值均出现在相对坡长的0.4 0.5处。坡面上各样地的平均土壤密度和坡面平均值的差值(Z,g.cm-3)随相对水平坡长(样地离开坡顶水平距离和整个坡面水平坡长的比)(X,m)变化的回归关系式分别为:华北落叶松坡面Z1=-0.139X2+0.25X-0.080 1(R2=0.93),天然灌丛坡面Z2=0.494 4X3-0.767 2X2+0.340 3X-0.040 5(R2=0.95)。[结论]华北落叶松林坡面和天然灌丛坡面的土壤密度都存在明显的坡位变化,但变化格局和主要影响因素不同。基于土壤密度坡面变化的拟合关系,可实现从特定坡位测定值推算坡面平均值的尺度转换。 相似文献
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Xingliang Liu Qinyan Ma Dongsheng Yang Zuoming Shi Yiming Su Shiqiang Zhou Shirong Liu Yupo Yang 《Frontiers of Forestry in China》2006,1(4):379-386
This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots
(Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m×25 m plot located
on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the
4 plantation types. To estimate the root biomass of an individual tree using D
2
H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm2 varied among plantation population types following the order: L. kaempferi (37.832 t/hm2) > A. fabri (24.907 t/hm2) > L. maxteriana (18.320 t/hm2) > P. balfouriana (15.982 t/hm2). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population
types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88%
for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0–20, 20–40, and 40–60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm2·m) for P. balfouriana, 8.230 t/hm2·m) for L. maxteriana, 24.546 t/(hm2·m) for A. fabri, and 13.211 t/(hm2·m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm2·year) for P. balfouriana, 0.83 t/(hm2·year) for L. maxteriana, 0.71 t/(hm2·year) for A. fabri and 1.64 t/(hm2·year) for L. kaempferi population, respectively.
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Translated from Acta Ecologica Sinica, 2006, 26(2): 542–551 [译自: 生态学报, 2006, 26(2): 542–551] 相似文献
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Mingdong Ma Chengde Luo Hong Jiang Yuejian Liu Xi Li 《Frontiers of Forestry in China》2009,4(2):140-145
Biomass, carbon content, carbon storage and spatial distribution in the 32-year-old Phoebe bournei artificial forest were measured. The mean biomass of the forest stand was 174.33 t/hm2, among which the arbor layer was 166.73 t/hm2, which accounted for 95.6%. Carbon contents of stems, barks, branches, leaves, root, shrub layer, herb layer, lichen layer
and litter layer were 0.5769 g C/g, 0.4654 g C/g, 0.5232 g C/g, 0.4958 g C/g, 0.4931 g C/g, 0.4989 g C/g, 0.4733 g C/g, 0.4143
g C/g, 0.3882 g C/g, respectively. The mean carbon content of soil was 0.0139 g C/g, which reduced gradually along with soil
depth. Total carbon storage of the P. bournei stand ecosystem was 227.59 t/hm2, among which the arbor layer accounted for 40.13% (91.33 t/hm2), the shrub layer accounted for 0.17% (0.38 t/hm2), the herb layer accounted for 0.76% (1.71 t/hm2), the lichen layer accounted for 0.28% (0.63 t/hm2), and the litter layer accounted for 0.29% (0.66 t/hm2). Carbon content (0–80 cm) of the forest soil was 58.40% (132.88 t/hm2). Spatial distribution ranking of carbon storage was: soil layer (0–80 cm) > arbor layer > herb layer > litter layer > lichen
layer > shrub layer. Net production of the forest stand was 8.5706 t/(hm2·a), in which the arbor layer was 6.6691 t/(hm2·a), and it accounted for 77.82%. Net annual carbon sequestration of the P. bournei stand was 4.2536 t/(hm2·a), and the arbor layer was 3.5736 t/(hm2·a), which accounted for 84.01%.
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Translated from Scientia Silvae Sinicae, 2008, 44(3): 34–39 [译自: 林业科学] 相似文献
15.
Forest precipitation chemistry is a major issue in forest hydrology and forest ecology. Chemical contents in precipitation
change significantly when different kinds of external chemical materials are added, removed, translocated and transformed
to or in the forest ecosystem along with precipitation. The chemistry of precipitation was monitored and analyzed in a 31-year-old
Pinus tabulaeformis forest in the West Mountain of Beijing. Movement patterns of nutrient elements in hydrological processes can be discovered
by studying this monitored data. Also, the information is useful for diagnosing the function of ecosystems and evaluating
the impact of the environment on the ecosystem.
Samples of rainfall, throughfall and stemflow were collected on the site. In the lab, Ca2+ and Mg2+ were analyzed by flame atomic absorption and K+ and Na+ by flame emission. NH4
+-N was analyzed by indophenol blue colorimetry and NO3
−-N was analyzed by phenoldisulfonic acid colorimetry. The results showed that: 1) The concentration gradient of nutrient elements
clearly changed except for Na+. The nutrients in stemflow were significantly higher than those of throughfall and rainfall as the precipitation passed through
the P. tabulaeformis forest. The monthly patterns showed distinct differentiation. There are indications that a large amount of nutrients was
leached from the canopy, which is a critical function of intra-ecosystem nutrient cycling to improve the efficiency of nutrient
use. 2) The concentrations of NO3
−-N and K+ changed more than those of the other nutrient elements. The concentration of NO3
−-N in throughfall and stemflow was 4.4 times and 9.9 times higher than those in rainfall, respectively. The concentration
of K+ in throughfall and stemflow was 4.1 times and 8.1 times higher than those in rainfall, respectively. 3) The leaching of nutrient
elements from the stand was an important aspect of nutrient return to the P. tabulaeformis forest, which returned a total amount of nutrient of 54.1 kg/hm2, with the contribution of Ca2+ and K+ much greater than that of other elements. Also, K+ was the most active element in leaching intensity. 4) Nutrient input through precipitation was the main source in the West
Mountain of Beijing and the amount of nutrient added was 66.4 kg/hm2, of which Ca2+ and N contributed much more than the other nutrient elements. When precipitation passes through the P. tabulaeformis forest, 121 kg/hm2 of nutrient is added to the forest floor. Ca2+ recorded the greatest nutrient increase, with 61.2 kg/hm2, followed by N (NH4
+-N and NO3
−-N), K+ and Mg2+, with 31.3 and 16.5, and 8.11 kg/hm2, respectively. The least was Na+, 3.34 kg/hm2.
Translated from Acta Ecologica Sinica, 2006, 26(7): 2,101–2,107 [译自: 生态学报] 相似文献
16.
The variation of fuel loads after a fire for three forest types,phododendron--Larix gmelinii forest,herb--Larix gmelinii forest andherb--Betula platyphlla forest, in the northern forest area of Daxing’anling region was discussed. The dynamic models were developed by gray theory
for estimating the fuels loads of arbor, shrub, herbs, grass, litter, and semi-decomposed litter, inflammable fuel and the
total fuels in each forest type. After a fire, the inflammable fuel loads inphododendron-Lxirix gmelinii forest and in the herb- -Betula platyphlla fores was estimated at 10.958 t/hm2 and 10.473 t/hm2 respectively, by 13 years later, and that was 12.297 t/hm2 inherb--Larix gmelinii forest by 7 years later. It was predicated that a big fire may occur after 10 years based on inflammable fuel biomass accumulated. 相似文献
17.
The sap flux density (SFD) was used as a measure of water capacity through stems of eucalyptus in this paper. It was found that daily SFD increased with daily vapor pressure deficit (VPD) in nonlinear regression Y=AX
3+BX
2+CX+D (R
2=0.702 1, n=135, p=0.01) at both sites (Hetou and Jijia) in the Leizhou Peninsula, Guangdong Province, China, where Y was daily SFD, X was mean daily VPD, A, B, C, D were constants. But extremely high VPD might limit stem water conductivity. The environmental factors, such as air vapor pressure deficit (VPD), solar radiation (RAD), etc., were the main determinants of SFD for E. urophylla plantations. The upper threshold of diurnal SFD was 51.55–55.65 mL·cm−2·h−1 under the selected extremely high environmental conditions. 相似文献
18.
杨树溃疡病经常在幼树干部形成大溃疡斑，造成枝枯和死树。以胸径下病斑面积与树周面积的比值计算的发病程度（X5）与胸径年生长量（Y2）之间呈显著相关。通过回归建立了三个品种不同病情下的生长量模型：美×559：Y2＝0．15406＋118．52194／（102．9113＋X^25)加杨：Y2＝－0．4136＋278．32113／（133．0115＋X^25)小×黑：Y2＝－0．08487＋110．16972／（131．4548＋X^25)三个估算模型经数学检验合理；坐标曲线符合植物病理学原理，可作为该病病情分级和生长量损失估算的参考。 相似文献
19.
[目的]通过构景因素控制试验,揭示林木胸径与密度对森林景观的影响规律,为林分密度调控提供参考。[方法]以枫香林为例,综合应用PhotoShop、AutoCAD、SpeedTree等软件,开展森林景观模拟;借助林业试验设计方法开展胸径、密度与景观美景度关系的两因素、单因素控制性试验。[结果](1)在设定的10个密度水平下,胸径变化对美景度(SBE)的影响总体不显著,景观优劣次序为20 cm30 cm10 cm;但若取各胸径级前3个高分SBE比较,则优先次序为30 cm20 cm10 cm;(2)密度对美景度的影响总体上为极显著,不同胸径级的美景度随密度变化均为先升后降趋势,以适中密度为最优,但随着树体的增大,峰值密度向左偏移,10 cm、20 cm、30 cm的最佳密度分别为1 389、833、389株·hm-2。密度-美景度曲线拟合结果为二次曲线,函数形式分别为SBE10=3.435+0.005X1-1.639E(-6)X12(R2=0.719)、SBE_(20)=4.013+0.004X2-1.677E(-6)X_2~2(R~2=0.713)、SBE_(30)=6.355+0.001X3-8.128E(-7)X32(R2=0.728);(3)胸径与密度的交互效应对美景度有极显著影响,但同一密度、同属随机分布的不同模拟场景对美景度的影响不显著。[结论]组合应用多种软件进行森林景观模拟与评价取得了良好结果,方法可行;林分美学质量受胸径、密度两个因素的综合影响,随着胸径增大而提高,但不同胸径有不同的最佳配密匹配度。 相似文献
20.
Mohammed Alamgir M. Al-Amin 《林业研究》2007,18(3):174-180
The organic carbon storage in trees and organic carbon flow with geoposition of trees was estimated in the forest area of Chittagong （South） Forest Division within geo-position 91°47′ and 92°15′ East longitude and 21°45′ and 22°30′ North latitude. The study was conducted through stratified random sampling by identifying each sampling point through Global Positioning System （GPS）. It was found that above ground organic carbon storage （t/hm^2）, below ground organic carbon （t/hm^2） and total biomass organic carbon （t/hm^2） was respectively the highest in Dipterocarpus turbinatus （Garjan） （7.9, 1.18 and 9.08 t/hm^2） followed by Tectona grandis （Teak） （5.66, 0.85 and 6.51 t/hm^2）, Artocarpus chaplasha （Chapalish） （2.32, 0.34 and 2.66 t/hm^2）, Artocarpus lacucha （Batta） （1.97, 0.29 and 2.26 t/hm^2） and Artocarpus heterophyllus （Jackfruit） （1.7,0.25 and 2.26 t/hm^2）. From the study it was revealed that organic carbon stock was the highest （142.7 t/hm^2） in the geo-position 22° Latitude and 92° Longitude and was the lowest （4.42 t/hm^2） in the geo-position 21° 50′ Latitude and 92° 2.5′ Longitude. The forest of the study area is a good reservoir of organic carbon so has a good capacity to sequester organic carbon from the atmosphere. Sustainable forest management may help to sequester more organic carbon so that economic benefit for the country and environmental benefit in the international arena are possible from the study area. 相似文献