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1.
苦竹叶片性状及其异速生长关系的密度效应   总被引：1，自引：0，他引：1       下载免费PDF全文
[目的]揭示苦竹叶片性状及其异速生长关系对密度的响应特征,为苦竹林培育适宜林分密度构建提供参考。[方法]开展了3种密度(低密度,14 430~16 545株·hm~(-2),L;中密度,31 590~34 560株·hm~(-2),M;高密度,54 120~55 560株·hm~(-2),H)苦竹纯林1~3年生立竹叶长(LL)、叶宽(LW)、叶面积(LA)、叶干质量(LM)等主要叶性因子测定,采用标准主轴回归分析解析叶性因子及其异速生长关系随密度的变异规律。[结果]研究表明:随着立竹年龄的增加,相同密度苦竹林的叶长、叶形指数和比叶面积均呈先升高后降低趋势,叶宽和叶面积总体呈降低趋势。随着密度的增加,相同年龄立竹叶长、叶宽、叶形指数、叶面积和比叶面积总体均呈先升高后降低趋势,其中,叶面积和比叶面积不同密度竹林间差异显著。3种密度苦竹林b_(LL-LA)、b_(LW-LA)、b_(LL-LM)、b_(LW-LM)及中密度、低密度苦竹林b_(LA-LM)均显著小于1.0,呈异速生长关系,而高密度苦竹林b_(LA-LM)接近1.0,呈等速生长关系。随着密度的增加,b_(LL-LA)、b_(LL-LM)呈先升高后降低趋势,而b_(LW-LM)、b_(LA-LM)则相反,且b_(LL-LA)、b_(LL-LM)和b_(LA-LM)不同密度竹林间差异显著。b_(LW-LA)随密度的增加呈升高趋势,中密度、低密度竹林间无显著差异,均显著低于高密度竹林。[结论]密度对苦竹林主要叶性因子及其异速生长关系会产生明显的影响,其中叶长对密度变化敏感,中密度(31 590~34 560株·hm~(-2))苦竹林具有较大叶长、叶宽、叶面积和比叶面积,因而具有较高的生产能力,是苦竹林培育的适宜密度。  相似文献   

2.
Granier’s probes were applied to measure the sap flow of 14 sample trees in an Acacia mangium forest on the hilly lands in Heshan City, Guangdong, during the time period of October, 2003. The photosynthetically active radiation (PAR), air relative humidity (RH) and temperature of air (T) above the forest canopy were recorded. The sap flow measurement was used in combination with morphological characteristics of tree and forest structure to calculate the whole-tree transpiration (E), stand transpiration (E t), and mean canopy stomatal conductance (g c). Analyses on the relationships between tree morphological characters and whole-tree water use, and on the responses of g c to PAR and vapor pressure deficit (D) were conducted. The results showed that whole-tree transpiration correlated significantly and positively with tree diameter at breast height (DBH) (p<0.0001), with sapwood area (p<0.0001), and with canopy size (p = 0.0007) logarithmically, but exponentially with tree height (p = 0.014). The analyses on the responses of canopy stomatal conductance showed that the maximum g c (g cmax) changed with PAR in a hyperbolic curve (p<0.0001) and with D in a logarithmic one (p<0.0001). The results obtained with sap flow technique indicate its reliability and accuracy of the methods of estimation of whole-tree and stand transpirations and canopy stomatal conductance. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(7): 1149–1156 [译自: 应用生态学报]  相似文献   

3.
The aim of this study was to develop a facile method for categorizing native celluloses as the algal-bacterial type or the cotton-ramie type and for estimating the Iα/Iβ (triclinic/monoclinic) ratio of the cellulose samples. We investigated various native celluloses by X-ray diffractometry; and discriminant analysis was carried out using two equatoriald-spacings: 0.59–0.62 nm (d 1) and 0.52–0.55 nm (d 2). All of the samples were classified into the two groups without error. The function used to discriminate between the two groups is represented as:Z=1693d1 — 902d 2 — 549, whereZ>0 indicates the algal-bacterial (Iα-rich) type andZ<0 indicates the cotton-ramie (Iβ-dominant) type. Another X-ray diffraction study of hydrothermally treatedCladophora cellulose revealed the relation between thed-spacings (d 1,d 2) and the Iα/Iβ ratio. A calibrating equation by which the Iα/Iβ ratio was estimated from the two parameters,d 1 andd 2, was then prepared. In the case of relatively highly crystalline native celluloses, it was found that the Iα/Iβ ratio is easily determined by applying the two parameters in the equation.  相似文献   

4.
[目的]研究北京海淀区3种道路防护林(油松林、圆柏林、银杏林)的滞尘能力、林内滞尘的空间分布规律、滞尘作用与气象因子和PM10浓度的相关性。[方法]滞尘量的测定用单位叶干质量滞尘量(mg·g-1)表征叶面滞尘能力。于冬、春、夏、秋4季对3种道路防护林内距道路不同距离处的滞尘量进行连续观测,比较3种道路防护林滞尘能力,分析3种道路防护林滞尘的空间分布特征及降雨等气象因子及PM10浓度与滞尘作用的相关性。[结果](1) 3种道路防护林总体单位滞尘量圆柏林(4. 20±0. 19 mg·g-1)银杏林(1. 98±0. 07 mg·g-1)油松林(1. 71±0. 07 mg·g-1);油松和圆柏林的单位滞尘量冬季春季秋季夏季,银杏林的单位滞尘量春季和秋季基本无差异,夏季最低; 3种道路防护林的单位滞尘量在各季节均为圆柏林最高,银杏林次之,油松林最低。(2) 3种道路防护林空间分布的总体特征为:油松和圆柏林的滞尘空间分布均表现为"两端高、中间低",银杏林单位滞尘量林分中间位置略高于两侧;不同季节表现为冬季北侧高,春季南侧高,夏、秋季南北侧差异不显著。(3)降水量对3种道路防护林滞尘作用影响最大,是3种道路防护林滞尘的最主要限制因子,极大风速、气温、相对湿度和PM10浓度对3种道路防护林滞尘均具有不同程度的正的直接作用。[结论]在相同配置模式(5 m×5 m)及林龄(18年)下,林地尺度滞尘量油松林最大、圆柏林次之、银杏林最低。道路防护林迎风一侧往往具有较高滞尘量,可根据盛行风向强化迎风侧的树木配置。降雨是树木滞尘的主要限制因子,冬季和春季降雨少,树木滞尘量较大,可结合人工冲洗措施使其发挥更大滞尘作用。  相似文献   

5.
Photosynthetic responses to a series of 1-min lightflecks (1,000μmol m−2 s−1) superimposed on a background with different duration (1, 5, and 10 min) and intensity (25 and 50μmol m−2 s−1) of low background photosynthetic photon flux density (PPFD) were measured in the leaves ofFagus crenata grown in a gap and understory of aFagus crenata forest in the Naeba Mountains. The two background PPFD intensities most frequently occurred in understory and gap sites respectively. The maximum net photosynthetic rate (P Nmax) and maximum stomatal conductance (g smax) were higher in the gap seedlings than in the understory seedlings. However, when the background PPFD was 25μmol m−2s−1, the net photosynthetic rate (P 25) and stomatal conductance (g s25) were almost the same between the gap and understory. When the background PPFD duration was 1-min, the net photosynthetic rate (P N ) at the end of each lightfleck increased progressively. When the background PPFD duration was 5- and 10-min, the increase inP N at the end of each lightfleck was less. This indicates that background PPFD duration is important to photosynthetic responses to lightflecks. The higher ratios ofP 25/P Nmax andg s25/g smax in the understory seedlings indicate that the understory seedlings can maintain relatively lower levels of biochemical and stomatal limitations than the gap seedlings under low light conditions. The ratios ofP N /P Nmax at the end of each lightfleck (IS) and light utilization efficiency of single lightflecks (LUE s) that showed the influence of lightflecks on carbon gain were higher in the understory seedlings than in the gap seedlings when the background PPFD was 25μmol m−2 s−1. This means that understory seedling are capable of utilizing fluctuating light more efficiently under low light conditions than the gap seedlings although the net carbon gain of single lightflecks (CG s) in the understory seedlings was not higher than that in the gap seedlings. There were no significant differences inIS andLUE s between understory seedlings at a background PPFD of 25μmol m−2 s−1 and gap seedlings at a background PPFD of 50μmol m−2 s−1. However,CG s in gap seedlings was higher than in understory seedlings. These results provide more evidence thatF. crenata acclimate to a natural light environment in respect to relative induction state at low background PPFD and can capture the fluctuating light at the same efficiency in both the gap and understory seedlings under natural light environments. This study was funded by the research project, Evaluation of Total CO2 Budget in Forest Ecosystems, coordinated by the Ministry of Agriculture, Forestry and Fisheries of Japan.  相似文献   

6.
Mean diameter by basal area (dg) is an important stand variable for long‐term economic forecasts of forest holdings. In order to use stand‐by‐stand surveys based on aerial photo interpretation as the data basis for forecasts, dg has to be determined. The objective was to develop and test a regression function for dg in mature stands of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) applicable in southeastern Norway. A study of 700 plots was used to estimate a function for dg . An additive model was found to be most suitable. The independent variables were potential yield capacity, Lorey's mean tree height, crown closure determined by ocular estimation by means of aerial photographs, and the product of potential yield capacity and crown closure. The R2 value was 0.604 and the coefficient of variation was 10.8%. The regression fitted most parts of the calibration data quite well, but it may overestimate the mean diameter in pure spruce stands by 1–2%, and underestimate the diameter in pure pine stands by 3%. For mixed coniferous stands the regression seems satisfactory. Testing by means of an independent data set showed systematic errors of 3–23%. The systematic errors were due partly to calibration problems in connection with the ocular crown closure estimation.  相似文献   

7.
Prince Rupprecht's larch (Larix principis-rupprechtii Mayr) stands growing at three different densities were investigated to determine characteristics of self-thinning. Tree density decreased with increasing stand age, and the higher density stand had higher mortality than the lower one. Mean stem volume increased with increasing stand age, and the higher density stand had higher relative growth rate of mean stem volume than the lower one. Mean stem volume (ν) increased with decreasing tree density (ρ), resulting in self-thinning line being expressed as ln ν=lnK-α ln ρ, whereK and α are coefficients. The slope of self-thinning line, —α, over the whole study period for all sites was similar with a mean value of —2.13. The ν-ρ trajectories before reaching the self-thinning slope of—3/2 could be described by Tadaki's model. The phase self-thinning line tended to decrease toward a slope of—3/2 with increasing stand age, which trends agreed with those of the published data of aPinus strobus stand andP. densiflora stands.  相似文献   

8.
We present results of individual-based root system measurement and analysis applied for Larix gmelinii trees growing on the continuous permafrost region of central Siberia. The data of root excavation taken from the three stands were used for the analyses; young (26 years old), mature (105 years old), and uneven-aged over-mature stand (220 years old). In this article, we highlight two topics: (1) factors affecting spatio-temporal pattern of root system development, and (2) interactions between aboveground (i.e., crown) and belowground (i.e., root) competition. For the first topic, the detailed observation of lateral roots was applied to one sample tree of the overmature stand. The tree constructed a superficial (<30 cm in depth) and rather asymmetric root system, and each lateral root expanded mainly into elevated mounds rather than depressed troughs. This indicated that spatial development of an individual root system was largely affected by microtopography (i.e., earth hummocks). For these lateral roots, elongation growth curves were reconstructed using annual-ring data, and annual growth rates and patterns were compared among them. The comparison suggested that temporal root system development is associated with differences in carbon allocation among the lateral roots. For the second topic, we examined relationships between individual crown projection area (CA) and horizontal rooting area (RA) for the sample trees of each stand. RA was almost equal to CA in the young stand, while RA was much larger (three or four times) than CA in the mature and overmature stands. Two measures of stand-level space occupation, crown area index (aboveground: CAI; sum of CAs per unit land area) and rooting area index (belowground: RAI; sum of RAs), were estimated in each stand. The estimates of RAI (1.3–1.8 m2 m−2) exceeded unity in all stands. In contrast, CAI exceeded unity (1.3 m2 m−2) only in the young stand, and was much smaller (<0.3 m2 m−2) in the two older stands. These between-stand differences in RAI–CAI relationships suggest that intertree competition for both aboveground and belowground spaces occurred in the young stand, but only belowground competition still occurred in the two older stands. Based on this finding, we hypothesized that competition below the ground may become predominant as a stand ages in L. gmelinii forests. Methodological limitations of our analysis are also discussed, especially for the analysis using the two indices of space occupation (CAI, RAI).  相似文献   

9.
Based on the widely used soil pore classification systems, soil pore ratios α, β and γ were derived. α, β, and γ represent ratios of the fine capillary porosity, coarse capillary porosity, and non-capillary porosity to the effective porosity, respectively. The parametersψ m and σ of the soil water retention model developed by Kosugi were related to these pore ratios, and a simple method was suggested to estimateψ m and σ from measured soil pore ratios. By analyzing the observed retention data sets of forest soils, it was shown that the soil pore ratios are effectively used to evaluate the soil pore radius distribution. A coordinate system with log(−ψ m ) on the abscissa and σ on the ordinate, which represents the constant α, β, and γ lines, was developed as a new diagram to evaluate the soil pore radius distribution in connection with the soil water retention characteristic. Then, the saturated hydraulic conductivityK s of forest soils was correlated with the parametersψ m and σ, and with the ratios α, β, and γ using the coordinate system and the triangle diagram. Results showed thatK s is higher for the soil with a greater median and with a greater width of the pore radius distribution.K s increases as the non-capillary pore ratio γ becomes greater and the coarse capillary pore ratio β becomes smaller. Functional relationships betweenK s and the water retention parameters, and betweenK s and the soil pore ratios were derived based on Mualem's model. The title is tentative translation from the original Japanese title by the author of this paper.  相似文献   

10.
Different multiple linear regression models of maximum leaf area index (LAImax) based on stand characteristics, site quality, meteorological variables and their combinations were constructed and cross-validated for three economically important tree species in Flanders, Belgium: European beech (Fagus sylvatica L.), Pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.). The models were successfully tested on similar datasets of experimental sites across Europe. For each species, ten homogeneous and mature stands were selected, covering the species’ entire stand productivity range based on an a priori site index classification. LAImax was derived from measurements of leaf area index (LAI) made by means of hemispherical digital photography over the whole growing season (mid-April till end October 2008). Species-specific models of LAImax for beech and oak were mostly driven by management practice affecting stand characteristics and tree growth. Tree density and dominant height were main predictors for beech, while stand age and tree-ring growth were important in the oak models. Scots pine models were more affected by site quality and meteorological variables. The beech meteorological model showed very good agreement with LAI at several European sites. Scots pine’s stand model predicted well LAI across Europe. Since the species-specific models did not share common predictors, generic models of LAImax were developed for the 30 studied sites. Dominant height was found to be the best predictor in those generic models. As expected, they showed a lower predictive performance than species-specific ones.  相似文献   

11.
Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii–Abies sachalinensis stand (PA stand) and a Larix kaempferi–Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha−1 for the PA stand and 24.3 Mg ha−1 for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fine roots were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have resulted from the limited available rooting space in the study sites.  相似文献   

12.
A synthetic method for obtaining lignin oligomer that contains only the β-O-4 structure is described in detail. This method consists of three reaction steps: (1) the synthesis of t-butoxycarbonylmethyl vanillin (2), (2) the nucleophilic addition oligomerization of compound 2, and (3) the reduction of the oligomeric β-hydroxyl ester. In the first step, compound 2 was synthesized from vanillin in 96.8% yield. In the second step, compound 2 was oligomerized with commercial lithium diisopropylamide (LDA) to obtain oligomeric β-hydroxyl ester (3) in 87.2% yield; the repeating units of this oligomer were joined only by β-O-4 linkages as confirmed by nuclear magnetic resonance (NMR) spectroscopy. In the third step, the oligomeric β-hydroxyl ester (3) was reduced with LiAlH4 to give compound 4 in 42.4% yield. On the basis of NMR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and gel permeation chromatography analyses of compound 4, it was concluded that compound 4 was an oligomeric lignin model compound containing only β-O-4 interunit linkages. The number average degree of polymerization (DPn) of obtained compound 4 was about 7.0 (M w/M n = 1.42). Using this oligomeric lignin model compound, conventional degradation and analytical methods will give new information.  相似文献   

13.
The allometric relationships between mean weights of components, such as stems, branches and leaves and tree weight as well as their time-trajectories, were studied with data of self-thinning Pinus densiflora stands with different densities. The allometric relationships existed between the weights of stems, branches and leaves and the tree weight during the course of self-thinning. The stem weight ratio increased with increasing tree weight because the allometric coefficient in stem was higher than unity, whereas the branch weight ratio and the leaf weight ratio decreased because the allometric coefficients in branches and leaves were less than unity. An allometric power relationship existed between mean component weight and mean tree weight during the course of self-thinning. The time-trajectory of mean component weight (w o) and density (ρ) in the early growth stage was expressed as a mathematical model which incorporates the allometric power relationship into the Tadaki’s model, whereas the model for describing w o-ρ trajectory in the later growth stage was derived by combining the allometric power relationship with 3/2 power law. The two models, Tadaki’s model and 3/2 power law, showed a good fit to data from P. densiflora stands. The time-trajectories of mean tree weight (w)-density (ρ) or w o-ρ initially almost moves nearly vertically in the low-density stand, moves along a steep curve and an inclined curve in the medium- and high-density stands, respectively, and gradually approaches self-thinning line in the early stage of stand development, whereas they reached and moved along the self-thinning line in the later stage of stand development. The self-thinning exponents were determined to be 1.71, 1.19 and 1.13 for the trees, 2.38, 1.33 and 1.20 for the stem, 3.16, 1.55 and 1.46 for the branches, 2.66, 1.39 and 1.35 for the leaves in the low-, medium- and high-density stands, respectively. The 3/2 power law of self-thinning is derived on the basis of simple geometric model of space occupation by growing trees, but allometric growth of tree and components can make the slope of the self-thinning line being different from −3/2. The reasons that the self-thinning exponents of components in the low-density stand were greater than those in the medium- and high-density stands were discussed.  相似文献   

14.
Pyrolysis reactions of various lignin model dimers   总被引：1，自引：0，他引：1  
Primary pyrolysis reactions and relative reactivities for depolymerization and condensation/carbonization were evaluated for various lignin model dimers with α-O-4, β-O-4, β-1, and biphenyl substructures by characterizing the tetrahydrofuran (THF)-soluble and THF-insoluble fractions obtained after pyrolysis at 400°C. Reactivity was quite different depending on the model structure: depolymerization: α-O-4 [phenolic (ph), nonphenolic (nonph)], β-O-4 (ph) > β-O-4 (nonph), β-1 (ph, nonph) > biphenyl (ph, nonph); condensation/carbonization: β-1 (ph) > β-O-4 (ph) > α-O-4 (ph) > β-O-4 (nonph), biphenyl (ph, nonph), α-O-4 (nonph), β-1 (nonph). Major degradation pathways were also identified for β-O-4 and β-1 model dimers: β-O-4 types: Cβ-O cleavage to form cinnamyl alcohols and phenols and Cγ-elimination yielding vinyl ethers; β-1 types: Cα-Cβ cleavage yielding benzaldehydes and styrenes and Cγ-elimination yielding stilbenes. Relative reactivities of these pathways were also quite different between phenolic and nonphenolic forms even in the same types; Cβ-O cleavage (β-O-4) and Cγ-elimination (β-1) were substantially enhanced in phenolic forms.  相似文献   

15.
Robinia pseudoacacia stands act as a typical ecological protection forest in hilly semi-arid area of China. Two fields of surface runoff were separately set up inR. pseudoacacia stand and its clearcut area in the western Liaoning Province (18°50’–122°25’ E, 40°24’–42°34’ N) for measuring the characteristics of runoff and sediment as well as soil moisture dynamics. Contractive analysis of the two land types showed that there existed a significant difference in volumes of runoff and sediment between the sites ofR. pseudoacacia stand and its clearcut area. The runoff volume and sediment volume in clearcut are were much bigger than those inR. pseudoacacia stand, with an increase amount of 40%–177% for runoff and 180%–400% for sediment. Hydrograph of surface runoff of typical rainfall showed that the peak value of runoff inR. pseudoacacia stand was decreased by 1.0–2.5×10−3m3·s−1 compared with that in its clearcut area, and the occurring time of peak value of runoff inR. pseudoacacia stand was 10–20 min later than that in its clearcut area. Harmonic analysis of soil moisture dynamics indicated that the soil moisture inR. pseudoacacia stand was 2.3% higher than that in clearcut area, and the soil moisture both inR. pseudoacia stand and its clearcut area could be divided into dry season and humid season and varied periodically with annual raifall precipitation. It was concluded thatR. pseudoacacia stand plays a very important role in storing water, increasing soil moisture, and reducing surface runoff and soil erosion. Foundation item: This paper was supported by Chinese “863” Plan Water-Saving Agriculture (2002AA2Z4321), the Key Knowledge Innovation Project (SCXZY0103), and The “Tenth-five” Plan of Liaoning Province (2001212001). Biography: GAO Peng (1967-), male, Dr. candidate, associate professor of Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan  相似文献   

16.
Carbohydrate model compounds methyl β-d-glucopyranoside (MGPβ), methyl α-d-glucopyranoside (MGPα), and methyl β-d-mannopyranoside (MMPβ) and the deuterium compounds of MGPβ labeled at the anomeric or C-2 positions (MGPβ-1D, MGPβ-2D) were reacted with active oxygen species (AOS) generated in situ by reactions between O2 and a co-treated phenolic lignin model compound, 4-hydroxy-3-methoxybenzyl alcohol (VAlc), under conditions simulating oxygen delignification (0.5 mol/l NaOH, 0.36 mmol/l Fe3+, 1.1 MPa O2, 95°C). MGPβ was degraded more than MGPα but less than MMPβ when the pairs MGPβ/MGPα and MGPβ/MMPβ, respectively, were treated, which indicates that the configurational differences at the anomeric and C-2 positions influence the reactivity of AOS toward these compounds. When the pairs MGPβ/MGPβ-1D and MGPβ/MGPβ-2D were treated, no clear kinetic isotope effects were observed in either case. These results contrasted with those obtained when another phenolic compound, 2,4,6-trimethylphenol (TMPh), was used as the AOS generator instead of VAlc under exactly the same conditions. Clear kinetic isotope effects were observed when using TMPh. Because it is not easily accepted that the anomeric and C-2 hydrogen abstractions are minor reaction modes only for AOS generated in the VAlc system, it is suspected that the AOS do not show any clear kinetic isotope effect even though the AOS abstract an objective hydrogen.  相似文献   

17.
We compare three or four years effects of crown release on stem growth rates among four deciduous broad-leaved tree species,Fagus crenata, Quercus crispula, Magnolia obovata andAcer mono, in an even-aged coppice forest, central Japan. The crown release significantly improved relative growth rates for basal-area (RGRBA) of the four species. However the effects of neighboring gap area (GAPA) on the RGRBA differed among the species. The effects were significant forQ. crispula andM. obovata, indicating that growth rates of these two species increase with intensity of the crown release. In contrast, the RGRBA ofF. crenata andA. mono were not correlated with the GAPA, suggesting that their growth rates are unrelated to the intensity. We considered that such differences among species were closely related to their photosynthetic characteristics of light use; less-tolerant species (Q. crispula andM. obovata) exhibit greater growth rates relative to the intensity of crown release than tolerant species (F. crenata andA. mono). Based on these results, we proposed implications for thinning practices in mixed forests of species with different shade-tolerance.  相似文献   

18.
An allometric model that explains the mechanism of the difference in the slope of the Reineke equation (A) among species was proposed based on the allometric relationships of mean tree height (H) to quadratic mean diameter D (H ∝ D θ ) and stand density N (H ∝ N δ ), i.e., A = θ/δ. The proposed model was fitted to Japanese cypress (Chamaecyparis obtusa Endl.) and red pine (Pinus densiflora) stands. The allometric exponents θ and δ were, respectively, 0.8995 and −0.5000 for cypress and 0.8612 and −0.6619 for pine. The difference between cypress and pine was significant for δ but not for θ. Inserting the exponents into the model resulted in predicted slopes of −1.7991 for cypress and −1.3011 for pine. The difference in the slope of the Reineke equation between the two species was produced by characteristics related to the tree crown, rather than characteristics related to stem slenderness. The proposed model enables us to estimate the slope of the Reineke equation from commonly measured stand attributes, such as mean tree height and quadratic mean diameter. Therefore, the proposed model is expected to be practical and convenient for estimating the slope of the Reineke equation and for explaining the mechanism of its variation among species. The model should be also accepted as a generalized model of the stand density versus quadratic mean diameter relationship, whereas the original Reineke equation should be seen as a specific case of this model.  相似文献   

19.
The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural Korean pine forest. The second is to research for tree architecture, growth and stand structure of artificial Korean pine (Pinus koraiensis) forests.The thesis compares the stand structure, process of regeneration, and various tree growth patterns between natural forests and artificial forests. Its purpose is to give a basis for forest management and silviculture. The study was carried out in Liangshui Experimental Forest Farm, which is located in the southern Xiaoxing’an Mountains.  相似文献   

20.
We derived an allometric model of the height–diameter curve for even-aged pure stands, which was a modification of the earlier model proposed by Inoue (2000a). An individual-dependent allometric equation was used as the height–diameter curve. Using the discriminant analysis method, all trees composed of a stand were stratified into upper and lower trees. It was assumed that both relationships between mean tree height H m and upper tree height H u and between mean DBH D m and mean DBH of upper trees D u could be described by the time-dependent allometric power equations. The height–diameter curve showed an average relationship between tree height and DBH of a given stand at a given time, and hence it could be assumed that the height–diameter curve contained two points (D m , H m ) and (D u , H u ). With these assumptions, we derived an allometirc model of height–diameter curve, which allowed the coefficients of the curve to be estimated from mean tree height and mean DBH. The proposed model was fitted to Japanese cedar (Cryptomeria japonica D. Don) data. The error ratio of the allometric model ranged from 2.254% to 13.412% (mean = 6.785%), which was significantly smaller than that of the earlier model. When the error of mean tree height was ±1.0 m or less, the effect of the error of mean tree height on the error ratio was comparatively small. This suggested that the error of ±1.0 m in mean tree height could be accepted in the estimation of height–diameter curve using the allometric model. These features enable us to combine the allometric model with Hirata’s vertical angle-count sampling or growth models. In conclusion, the allometric model would be one of the most practical and convenient approaches for estimating the height–diameter relationship of even-aged pure stands.  相似文献   

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