Rooted Tree Optimization for Wind Turbine Optimum Control Based on Energy Storage System

The integration of wind turbines(WTs)in variable speed drive systems belongs to the main factors causing lowstability in electrical networks.Therefore,in order to avoid this issue,WTs hybridization with a storage system is a mandatory.This paper investigates WT system operating at variable speed.The system contains of a permanent magnet synchronous generator(PMSG)supported by a battery storage system(BSS).To enhance the quality of active and reactive power injected into the network,direct power control(DPC)scheme utilizing space-vector modulation(SVM)technique based on proportional-integral(PI)control is proposed.Meanwhile,to improve the rendition of this method(DPC-SVM-PI),the rooted tree optimization technique(RTO)algorithm-based controller parameter identification is used to achieve PI optimal gains.To compare the performance ofRTO-based controllers,they were implemented and tested along with some other popular controllers under different working conditions.The obtained results have shown the supremacy of the suggested PIRTO algorithm compared to competing controllers regarding total harmonic distortion(THD),overshoot percentage,settling time,rise time,average active power value,overall efficiency,and active power steadystate error.

Modeling tree root diameter and biomass by ground-penetrating radar

Roots play a key role in ecosystem functioning as they transfer water and nutrients from soil to plants. Traditional methods for measuring roots are labor-intensive and destructive in nature, which limits quantitative and repeatable assessments in long- term research. Ground-penetrating radar （GPR） provides a non-destructive method to measure plant roots. Based on the superiority of GPR with 2 GHz frequency, we developed a new, practical method to estimate root biomass. First, average root matter density was measured by collecting a small number of root samples. Second, under controlled, experimental conditions in a sandy area, a root diameter estimation model base on GPR was developed from which root diameter was estimated. Third, root volume was calculated using the estimated root diameter and assuming the shape of roots to be cylindrical. Finally, root biomass was estimated by averaging root matter density and root volume. Results of this study suggest the following： （1） the density of coarse roots with diameters greater than 0.5 cm is relatively uniform; （2） a new wave shape parameter, AT, extracted from profile data of 2 GHz frequency antenna is independent of root depth, thus enabling the construction of a root diameter estimation model with high accuracy; and （3） results of a field experiment demonstrated the GPR-based method to be feasible and effective in estimating biomass of coarse roots. These findings are helpful for improving GPR-based root diameter and biomass estimation models and suggest the potential of GPR data in studying root systems.

Roots of pioneer trees in the lower sub-tropical area of Dinghushan, Guangdong, China

Representative pioneer tree root systems in the subtropical area of South China were examined with regard to their structure, underground stratification and biomass distribution. Excavation of skeleton roots and observation of fine roots of seven species including the Euphorbiaceae, Theaceae, Melastomataceae, Lauraceae and Fagaceae families was carried out. The results showed that： （1） Pioneer tree roots in the first stage of natural succession were of two types, one characterized by taproot system with bulky plagiotropic branches; the other characterized by flat root system with several tabular roots. The late mesophilous tree roots were characterized by one obvious taproot and tactic braches roots up and down. Shrub species roots were characterized by heart fibrous root type featured both by horizontally and transversally growing branches. Root shapes varied in different dominant species at different stages of succession. （2） Roots of the different species varied in the external features-color, periderm and structure of freshly cut slash. （3） In a set of successional stages the biomass of tree roots increased linearly with the age of growth. During monsoon, the total root biomass amounted to 115.70 t/ha in the evergreen broadqeaved forest; 50.61 t/ha in needle and broad-leaved mixed forest dominated by coniferous forest; and 64.20 t/ha in broad-and needle-leaved mixed forest dominated by broad-leaved heliophytes, and are comparable to the underground biomass observed in similar tropical forests. This is the first report about roots characteristics of forest in the lower sub-tropical area of Dinghushan, Guangdong, China.

Analysis of channel bank erosion rate using exposed roots of trees: a case study of lavij stream, northern Alborz Mountains, Iran

Powerful alluvial rivers in the northern Alborz mountain ranges erode river banks due to having high slopes.Most of these rivers flow in forest areas.In this research,the rate of the river bank erosion was examined using the exposed roots of the trees.For this purpose,8 reaches of Lavij Stream were investigated.To determine the first year of root exposure,two sets of macroscopic and microscopic indicators were utilized.Accordingly,the rate of the stream bank erosion was estimated.The results were analyzed by using statistical test,which showed insignificant differences between the two groups of indicators.Due to its more abundance(frequency)on the margins and easy detection of its root through the exposure(macroscopic and microscopic)indicators,Alnus glutinosa(black alder)species could be more easily and accurately analyzed as compared with any other tree species in the region.The mean erosion rate of the riverbank using the extruded roots was estimated to be 0.08 m/yr.The hydrological analyses of flood flows showed that 95%of Lavij Stream bank erosion was caused by the river bank full discharges with a return period of 1-3 years.

Effect of Indole 3-Butyric Acid and Media Type on Adventitious Root Formation in Sheanut Tree (<i>Vitellaria paradoxa</i>C. F. Gaertn.) Stem Cuttings

Shea nuts play an important role in food security for rural folks within sub-Sahara Africa, serving as the main source of income for many people living in Northern Ghana. Unfortunately, the full economic potential of the Sheanut tree has not been fully realized due to the difficulty involved in its domestication. This difficulty in vegetatively propagating sheanut trees has greatly hindered its cultivation and the realization of its true economic potential. Two experiments were conducted to investigate the effects of rooting media and varying indole 3-butyric acid (IBA) concentrations on adventitious root formation in cuttings taken from coppiced sheanut trees. Results indicated that 3000 ppm produced significantly (p 0.05) better rooting (57.5%) than 5000 ppm (30%), 7000 ppm (45.0%) and the control (7.5%). Although the levels of soluble sugars (SS) and total free phenols (TFP) in the cutting were significantly (p 0.05) higher at the end of the experiment (after IBA treatment) compared to the start (prior to IBA treatment), the SS and TFP trends observed did not clearly explain the rooting differences found between the IBA levels investigated. Callus formation was significantly (p 0.05) higher (35.0%) in the control (no IBA). Generally, callus formation decreased with increasing IBA concentration. In the rooting media experiment, rooting was significantly (p 0.05) higher in the rice husk medium (35.0%) compared to that in the palm fiber (18.3%), saw dust (14.1%) and top soil (16.7%) media.

Vertical Distribution and Seasonal Dynamics of Fine Root Parameters for Apple Trees of Different Ages on the Loess Plateau of China

The vertical distribution pattern and seasonal dynamics of fine root parameters for the apple trees of different ages （3, 10, 15, and 20 years old） on the Loess Plateau of China were studied. Soil coring method was used to determine the vertical distribution and seasonal dynamics of fine roots at different root radial distances （1.0, 1.5, and 2.0 m from the main tree trunk）. The fine root biomass density （FRD）, fine root length density （RLD）, and specific root length （SRL）, as well as soil water content and soil temperature were also measured. The FRD and RLD for the 10, 15, and 20 years old trees reached peak values in the 20-30 cm soil layer. For the 3 years old tree, the highest FRD and RLD were observed in the 10-20 cm soil layer. The FRD and RLD decreased with increased soil depth from the 10-20 or 20-30 cm soil layer for all age apple trees. The SRL declined with the increase of tree age. The FRD at the 1.0 m radial distance from the main tree trunk was higher than that at other radial distances in the 3 and 10 years old orchard. However, in the 15 and 20 years old orchards, especially the 20 years old orchard, the FRD at the 2.0 m radial distance was nearly equal to or higher than that at the 1.0 and 1.5 m radial distances. For all the root radiuses or the tree ages, the FRD, RLD, and SRL were the highest in spring and the lowest in autumn. The age of an apple tree does not affect the vertical distribution pattern but the biomass of fine roots and the SRL. Radial distance affects the root horizontal distribution of 3 and 10 years old trees but the 15 and 20 years old trees. Additionally, effects of soil temperature and soil moisture on fine root distribution or seasonal dynamics are not significant.

Brief Investigation on Square Root of a Node of <i>T</i>₃Tree

The article investigates some properties of square root of T3 tree’s nodes. It first proves several inequalities that are helpful to estimate the square root of a node, and then proves several theorems to describe the distribution of the square root of the nodes on T3 tree.

防治橡胶树褐根病0.5%戊唑醇膏剂的研制

由木层孔菌属有害层孔菌Phellinus noxius Corner引起的褐根病是我国橡胶树的主要根部病害之一。生产上常用挖隔离沟和灌根施药方式进行防治,但其耗费人力物力,防治成本高。为了寻求经济高效且环保的新技术,本研究通过对不同杀菌剂、填料、增稠剂、渗透剂和保湿剂进行筛选,制备了一种防治橡胶树褐根病的膏剂。随后,通过对外观、附着性、黏度、pH值、稳定性、成膜性及固含量流失率等性能指标的综合评价,确定了膏剂的最佳配方为:0.5%(质量分数,余同)戊唑醇、20%纳米硅藻土、2%羧甲基纤维素钠、6%乌迪尔树皮穿透剂、5%凡士林、5%棕榈油、5%乙二醇,余量为水。制备的膏剂为乳白色黏稠状,呈弱碱性,附着性强,黏度高,冷热储合格,成膜薄且有韧性,膜的固含量流失率为13.95%,耐雨水冲刷能力强。0.5%戊唑醇膏剂经过橡胶植株茎基部施药,通过气相色谱-串联质谱(GC-MS/MS)结合QuEChERs法检测橡胶根中戊唑醇的含量。结果表明,施药后24 h即可在植株根部检测到戊唑醇,96 h含量达到5.49 mg/kg,说明戊唑醇能穿透茎部树皮向下传导至根部。综上所述,膏剂剂型的研制为橡胶树褐根病的化学防治提供了一种新途径。

橡胶灵芝菌内参基因筛选与分析

【目的】分析评价不同胁迫处理的橡胶灵芝菌候选内参基因的稳定性,为探索橡胶灵芝菌基因的功能及其侵染橡胶树的分子机制等提供参考。【方法】以5个非生物因子(温度、盐、氧化、pH、干旱)和1个生物因子(生防细菌)胁迫下的橡胶灵芝菌作为材料,提取RNA并反转录为cDNA,采用实时荧光定量PCR技术,扩增6个候选内参基因(UBC、ACT、RPL6、β-TUB、APT、28s),利用分析软件geNorm、NormFinder、BestKeeper和RefFinder根据基因表达的稳定性对基因进行排序,选择最适合不同胁迫的内参基因组合。【结果】所有样品RNA均为清晰的两条带,且6个候选内参基因的熔解曲线为明显单一峰。结合geNorm、NormFinder、Bestkeeper和RefFinder对其进行表达稳定性分析发现,温度胁迫下基因表达稳定性为UBC>ACT>RPL6>β-TUB>28s>APT,盐胁迫下基因表达稳定性为ACT>RPL6>UBC>APT>β-TUB>28s;氧化胁迫下基因表达稳定性为UBC>ACT>28s>APT>β-TUB>RPL6;pH胁迫下基因表达稳定性为RPL6>UBC>APT>ACT>β-TUB>28s,干旱胁迫下基因表达稳定性为ACT>UBC>β-TUB>RPL6>APT>28s,生物胁迫下基因表达稳定性为UBC>ACT>RPL6>28s>APT>β-TUB。【结论】结合所有候选基因稳定性和胁迫条件,推荐基因ACT和UBC作为在干旱、氧化、温度和生物胁迫下的内参基因,基因ACT和RPL6为盐胁迫下的内参基因,UBC和RPL6为pH胁迫下的内参基因。本研究结果为不同胁迫下橡胶灵芝菌相关基因的表达研究提供了合适的内参基因。

闽楠-木荷混交林空间结构及其养分利用

【目的】为探讨混交林中闽楠和木荷的种间关系,确定木荷能否作为闽楠的伴生树种营建健康高效的闽楠-木荷混交林。【方法】以金洞林场16年生的闽楠-木荷混交林以及闽楠纯林、木荷纯林为研究对象,通过分析闽楠-木荷混交林的根系分布特性与林分空间结构特性来探讨闽楠-木荷混交林地上与地下部分的种间关系;通过分析不同物候期下3种林分的闽楠与木荷叶片养分的动态规律来阐明闽楠与木荷之间的养分利用关系。【结果】1)在16年生闽楠-木荷混交林中,在闽楠周围1.5 m内闽楠和木荷的根系分布虽有部分重叠,但闽楠仍占据优势地位,闽楠和木荷在地下生长空间和养分吸收利用方面存在竞争但竞争不激烈;2)整体林分空间结构上,闽楠、木荷纯林略优于闽楠-木荷混交林,说明混交林的树种不同,树种之间的生长特性和生态特性不一样,林分的均一性会差一些,对其调整结构的难度要大于纯林。混交林中,木荷已对闽楠形成了一定的竞争优势;3)闽楠-木荷混交林中,对养分吸收利用在物候期上部分不同步,存在相对有利的互补关系;从所有的物候期来看,闽楠叶片的N、P、K含量在大部分时期都高于木荷,表明闽楠-木荷混交更有利于闽楠对养分的吸收利用,木荷对养分的需求更低;4)16年生混交林中闽楠、木荷的生长速度要优于相应的纯林,表明前期竞争促进了林分的生长。【结论】闽楠与木荷混交有利于闽楠获得更多的养分,适度竞争促进了林木的生长,木荷是闽楠较好的伴生树种。

母树年龄和复幼对锥栗插穗生理及不定根发生的影响

【目的】探讨母树年龄及基部促萌复幼对锥栗Castanea henryi半木质化嫩枝扦插生根的影响,从生理水平和解剖结构特征解析其可能原因,为锥栗扦插繁殖提供理论和实践指导依据。【方法】对2年生和8年生锥栗母树分别进行基部截干促萌复幼处理,以当年生半木质化的新枝为试材,以不截干枝条为对照,分别于扦插后0、7、14 d取插穗基部,通过制作石蜡切片对插穗生根部位进行解剖观察,测定可溶性糖含量、可溶性蛋白含量、木质素含量、氧化酶活性、激素水平的动态变化,并于扦插后60 d统计各处理的扦插生根率和生根数量。【结果】1)扦插14 d后,可见2年生锥栗插穗有不定根长出,8年生锥栗插穗基部有白色突起。2)母树年龄越大,扦插生根率越低,且基部促萌复幼对锥栗插穗不定根的影响不显著(P>0.05)。2 a对照、2 a复幼的生根率(68.0%、70.0%)和每插穗不定根数量(11.3、10.6)显著高于8 a对照和8 a复幼的生根率(3.2%、4.4%)和每插穗不定根数量(3.2、2.9)(P<0.05)。3)8 a插穗木质素含量在不定根发生过程中显著高于2 a插穗(P<0.05),且复幼不能降低插穗木质素含量。扦插7 d后8 a插穗的可溶性蛋白含量在对照和复幼处理中均显著低于2 a插穗(P<0.05)。4)在不定根发生过程中,IAAO酶活性在不同年龄和复幼插穗间差异均不显著(P>0.05);8 a插穗的IAA水平显著高于2 a插穗(P<0.05)。扦插7 d后,2 a锥栗插穗的SOD显著高于8 a锥栗插穗(P<0.05),8 a插穗的GA3含量显著高于2 a插穗(P<0.05)。【结论】母树年龄是影响锥栗插穗不定根发生的主要要素,单纯基部平茬促萌复幼措施可能不适宜被用来提高锥栗成年插穗的不定根发生率。调控木质素的合成和代谢途径可能是提高锥栗成年插穗不定根发生的关键。

FracRoot模型在橡胶树根系研究上的应用初探

以30年生的3个品种的橡胶树为参试材料建立根系模型。测量根系拓扑、分枝规律、连结长度、连结直径和根系分枝角度,将这些数据应用于FracRoot模型,对橡胶树根系分段数量、总长度和生物量进行预测。结果表明,根段的逐渐变细对参数α值有很大影响,FracRoot模型轻微的低估了RRIM600和PR107中根系的分段数量和总长度,高估了GT1分段数量和总长度;过高的估计了所有物种的单一根系总的生物量;过低预测根系的水平分布,而过高的估计了垂直分布。

基于现场原型测试的乔木覆盖滑坡区根-土复合体力学性能研究

为揭示乔木根系力学特性及其对斜坡的力学效应,选取福建武平高植被覆盖区滑坡为研究点,对研究区典型乔木根系按径级分类后进行根系抗拉力学特性测试,并在滑坡现场进行不同根系横截面积比(rootcross-sectionalarearatio,简称RAR)、含水率下的根-土复合体原位直剪试验以及剖面根系分布特征调查,对根系在浅层滑坡的力学效应展开探究。研究结果表明:(1)1~7径级下马尾松、杉木抗拉力范围为12.45~673.09 N,抗拉力与根径呈幂函数正相关;抗拉强度范围为7.16~60.95MPa,抗拉强度与根径呈幂函数负相关。杉木根系平均抗拉力与抗拉强度均大于马尾松。(2)乔木根系显著提高了土体抗剪强度,根系对土体提供的附加黏聚力与剪切面RAR显著正相关。杉木根系构型更接近R型,马尾松为VH型,相近RAR下杉木对土体的加固作用优于马尾松。(3)随着含水率增加,马尾松、杉木根-土复合体抗剪强度显著下降,水分入渗使根系对土体提供的附加黏聚力受到削减。(4)基于Wu模型,考虑水分对土体黏聚力与根系附加黏聚力的影响,建立了考虑含水率的根-土复合体抗剪强度值估算模型,经检验,精度高于Wu模型,结果较为合理。(5)根系对浅层滑坡虽然具有加固作用,但受到根系分布深度、密度以及降雨等因素限制,强降雨作用下根系对浅层滑坡稳定性贡献具有局限性。

紫金山3种优势乔木细根功能性状的序级变化特征

【目的】明晰紫金山3种优势乔木细根功能性状在序级间的变化特征,为深入理解不同根序细根在地下生理生态过程中的作用提供理论依据。【方法】以紫金山3种优势乔木糙叶树、朴树和枫香为对象,采用随机区组设计设置3个20 m×20 m的样方,采集优势树种的细根,分析不同树种细根直径、比根长、比表面积、根组织密度、C、N及P含量等功能性状随序级的变化特征。【结果】1)树种对细根形态性状和化学性状都有显著影响,而序级只对细根直径、比根长、比表面积、细根N、P含量和C/N有显著影响。2)随着序级升高,3种优势乔木的细根直径和C/N呈现增加趋势,比根长、比表面积、N含量和P含量整体呈现减小趋势,根组织密度和C含量随序级增加没有明显的变化规律。3)在1~5级根中,朴树的直径最小,比根长和比表面积最大;糙叶树的根组织密度最大;朴树的C含量最高;枫香的C/N最小。在1级根中,糙叶树的N含量最高,朴树的P含量最高。糙叶树和枫香的细根生物量随着序级升高而增加,朴树的1级根生物量大于2、3级根生物量。4)主成分分析表明,3种优势乔木的细根功能性状分为两个变异维度,糙叶树偏向于资源获取型,朴树偏向于自主觅食资源获取型,而枫香偏向于不同策略的权衡。【结论】细根功能性状和多维度根系策略在树种之间存在差异,表明糙叶树和朴树细根对养分的获取效率较高,枫香细根养分获取效率较低;但枫香细根的分解速率可能快于糙叶树和朴树。

苹果根腐病调查及绿色防控

根腐病是苹果树毁灭性病害之一,目前该病防治多化学制剂为主,导致土壤水源环境污染,果树抗病能力降低。本文旨在探索生物防治苹果根腐病新思路:通过使用生物制剂哈茨木霉菌等生防制剂代替传统化学制剂防治苹果根腐病。试验表明使用2.0亿/g哈茨木霉菌+350亿/g解淀粉芽孢杆菌+5亿/g枯草芽孢杆菌+52%矿源黄腐酸钾+35 g/L聚谷氨酸,按产品说明用量进行2次灌根处理,能够快速抑制、杀灭土壤有害菌,大幅度降低根腐病危害,提高苹果树势、产量、品质和果园效益。

基于TRU系统的深圳城市绿地优势观花树种根系空间分布特征

为促进城市绿地优势观花树种健康管理,以深圳城市绿地优势观花树种为研究对象,采用树木雷达系统(Tree radar unit,TRU)检测方法,对火焰木Spathodea campanulata、凤凰木Delonix regia、美丽异木棉Ceiba speciosa、黄花风铃木Handroanthus chrysanthus进行根系检测,探寻不同树种、不同立地下根系分布特征。结果表明,(1)整体而言,根系水平分布的特征为距离树干越远,根系密度越小。不同树种水平根系分布密度存在显著差异(P<0.05)。(2)垂直方向根系分布以20~40 cm土层密度最高,而0~20 cm、40~60 cm土层范围根密度较小,绝大多数根系分布在0~60 cm范围土层中。(3)不同树种总体垂直分布密度差异显著(P<0.05),随土层深度增加呈先增加后减小规律,通常于20~40 cm土层范围内达到峰值。(4)道路立地与硬质铺装环境根系相比于草坪绿地具有更明显的胁迫响应,根系为应对胁迫普遍采取侧重于分支生长的策略,具体表现为道路立地与硬质铺装环境下相同树种水平与垂直根系密度远高于草坪绿地,且在表层土壤根系形成聚集效应,表层土壤范围内根系含量相比草坪绿地显著增加(P<0.05)。总体根系密度呈道路立地>硬质铺装>草坪绿地。(5)在城市硬质环境胁迫下,各树种根系横向扩张能力呈凤凰木>火焰木>美丽异木棉>黄花风铃木。为了改善城市绿地树木的根系发育,建议采用土壤改良、生根剂施用、新型基质换填和菌根形成诱导等方法,并结合引根管、隔根挡板、树池和绿化带的工程技术改造,以促进根系健康发展。

调亏灌溉对滴灌核桃树根系空间分布特征的影响

【目的】分析小于2 mm的根系滴灌核桃有效吸水根系分布特性,建立有效根长密度函数,研究不同调亏灌溉对核桃树根系空间分布特性,为滴灌核桃精准调亏灌溉提供理论依据。【方法】以14年生温185核桃树为试材,采用30 cm×20 cm×20 cm的分段分层法,取样分析有效吸水根系(d<2 mm)分布特征,研究调亏灌溉对滴灌核桃树有效根系空间分布的影响。【结果】在不同调亏灌溉处理中,W_(0)、W_(3)、W_(4)的核桃树有效总根长分布总体变化趋势表现为单峰曲线,且各个调亏处理在20~40 cm有效总根长最大,分别为50959、74067、55678 cm。不同处理下垂直方向根长密度一维符合指数分布,且水平方向根长密度符合多项式分布。W_(0)、W_(3)、W_(4)各处理有效根长均表现出土层深度在20~40 cm,在距离核桃树行向30~60 cm处最大,分别为11794、22753、14119 cm。【结论】不同调亏灌溉处理下,滴灌核桃树根系有效生长密度表现为W_(3)>W_(4)>W_(0),调亏滴灌灌溉模式使核桃吸水根系更靠近地表生长。

果园树干检测与导航线拟合算法研究

行间机械自主导航有助于提高果品生产效率,降低人工成本。树木是行间导航的天然地标,可以为机器人提供导航信息。结合深度学习和最小二乘法,提出一种基于机器视觉的行间导航场景的导航线提取方法。首先,收集实际环境下的树干图像,并对图像进行翻转、裁剪等操作扩充树干数据集;其次,构建YOLOv5网络模型,并基于该模型来对行间树干进行识别,提出利用识别框下边中点替换根部中点的方法,以此来确定树行拟合的定位基点;最后,基于最小二乘法完成果园单侧树行线和树行中心线的拟合。试验结果表明,所构建的YOLOv5网络检测模型对树干的平均识别正确率为85.5%。所提出的根点替换定位法的直线像素距离平均误差为5.1像素,树行中心导航线的平均横向偏差为5.8像素,符合行间导航的要求。

有向根树上局部更新函数为NAND或NOR的广义并序动力系统的固定点

研究对象为有向根树上的广义并序动力系统,其局部更新函数为NAND或NOR。为了研究这类广义并序动力系统中的固定点的个数及状态,采用结构分析法和分类讨论法,得到了此类动力系统中关于固定点的确切结果。证明了这类广义并序动力系统中的固定点状态完全由有向根树中的自环决定。离散动力系统是数学建模的重要工具,该文可为离散动力系统的研究提供新的思路。

福建桉树异速生长方程与生物量估算

以中国南方主要速生丰产树种桉树为研究对象,利用野外破坏性实测的90棵桉树解析木数据,研究桉树单木器官生物量的分配及规律,构建最佳单木异速生长方程,计算桉树根冠比并将其应用于桉树树根生物量的估算。结果表明:1)桉树生物量的分配策略如下:随着林龄的增大,桉树树干的生物量分配比例不断增多,而树枝、树叶和树根的生物量分配比例不断减少。2)应用桉树分林龄的根冠比数据估算桉树树根生物量是最为可行且有效的方法。3)在桉树生物量的异速生长方程构建中,乘幂方程优于线性方程,最优自变量则根据各器官有所差异。