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1.
The profitability to smallholders of rubber production in Imperata infested areas of Indonesia was assessed using an existing bioeconomic model. An Imperata groundcover component was incorporated within the model as follows: tree girth = f(Imperata groundcover) = f(relative shading) = f(crown height, canopy width, tree spacing) = f(tree girth). The first two relationships represent extensions to the original model.Cumulative tree girth was predicted for rubber planting densities from 400 to 1000 stems/ha. At low tree planting rates, competition from Imperata restricts tree growth. At high tree planting rates, Imperata is controlled, but there are negative consequences from inter-tree competition. These two effects of higher planting rates counterbalanced, such that tree girth was approximately constant across the range of tree densities.Tree girth is a driving force in determining latex yield. Latex yield was translated into present value net economic returns within the model, by reference to prices and costs associated with rubber production in South Sumatra, Indonesia in 1995. Economic returns from planting 400 to 1000 trees/ha were calculated. Rubber growing by smallholders on Imperata infested land, was found to be profitable. Maximum profitability was obtained at 600 trees/ha. However, the sensitivity of net economic returns, with respect to tree density, was not great. This was due to the counterbalancing effects of changes in tree density. 相似文献
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F. C. Do A. Pierret P. Couteron G. Lesturgez L. Boithias S. Isarangkool Na Ayutthaya J. Junjittakarn S. Gonkhamdee J. L. Maeght C. Hartmann D. Nandris 《Forest Pathology》2011,41(2):90-100
Trunk phloem necrosis (TPN) is a major constraint in rubber (Hevea brasiliensis) plantations. Current knowledge supports a scenario of a multi‐factor physiological ‘disease’ caused by an accumulation of endogenous and exogenous stresses. Without evidence of a pathogen, the apparent spread of the syndrome from tree to tree along the planting line, strongly suggested the implication of a major local soil constraint. The objectives of the study were to address, within a plot, three points of the above scenario: the short‐distance aggregation of affected trees; their correspondence with local micro‐areas facing the highest environmental constraints; and the relative weakness of TPN trees that had accumulated several stresses since planting. The study was conducted in a young rubber tree stand (clone RRIM 600) of Northeast Thailand, where the number of TPN affected individuals was 8% after 3 years of tapping. Trunk girth and trunk basal area were used as indicators of local environmental constraints. Spatial patterns were analysed using the framework of marked point processes and K functions. The results confirmed the short‐distance aggregation of TPN affected trees. But, TPN trees were not located within micro‐areas where trees had a lower trunk basal area than average. Hence, the clusters of TPN do not occur in the most constraining environmental micro‐areas of the plot in terms of growth since planting. Moreover, from comparison of girth, current girth increment and height of bark consumption, we infer that TPN trees were not smaller and less vigorous than other trees before the syndrome outbreak. Finally, our conclusions mean the previous scenario driven by major soil constraints becomes a ‘more complex scenario’ in which specific soil conditions (not the most constraining in term of cumulated growth), possibly in interaction with inter‐individual competition, induce a late and subtle stress favouring a necrotic reaction against tapping stress. 相似文献
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Silpi U Thaler P Kasemsap P Lacointe A Chantuma A Adam B Gohet E Thaniswanyankura S Améglio T 《Tree physiology》2006,26(12):1579-1587
Rubber tree (Hevea brasiliensis Müll. Arg.) radial growth dynamics were monitored with displacement sensors, together with latex production, to investigate three aspects of the dual production of latex and wood: (1) the usefulness of fine-scale dendrometric measurements as a physiological tool to detect water shortage through radial growth; (2) the dynamic aspects, both at the seasonal and at the multi-year scale, of the competition between latex and wood production; and (3) the spatial distribution of radial growth rates around the tapping cut. Radial growth of untapped control trees started with the onset of the rainy season and lasted until the onset of the dry season, ceasing completely during the driest period. Displacement sensors provided a sensitive means of detecting water shortage, with a clear correlation between diameter variations and changes in water availability (both daily evapotranspiration and monthly rainfall) over the whole annual cycle. However, the correlation was significantly disturbed in tapped trees. After resumption of tapping, the radial growth rate dropped sharply within two weeks and the effect persisted throughout the whole season, so that the cumulative growth of tapped trees was about half that of untapped trees, with the cumulative growth deficit reaching 80% for the period from mid-June to November. This long-known negative impact of tapping on growth was much stronger in the second year of tapping than in the first, whereas latex production increased significantly between the first and second year of tapping. The increased latex production, which could not be ascribed to climatic conditions, shows that the establishment of an artificial latex sink is a progressive, long-term process likely involving many aspects of metabolism. As expected, ethylene significantly increased latex production in both years; however, ethylene had no effect on the growth rates of tapped trees. Radial growth was differentially affected at different locations around the tapping cut, with growth rates significantly lower in the tapped panel than in the untapped panel, and higher above the cut than below the cut. Thus, caution is needed when deriving whole stem wood production from girth measurements at one location on the stem, especially from girth measurements made close to the tapping cut. This also provides new evidence for the location of the latex regeneration area in the tapped panel, below the cut. 相似文献
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《林业研究》2016,(4)
Hevea brasiliensis is a commercially cultivated species for its natural rubber(NR) latex in South East Asian countries. To meet the ever-increasing demand, NR cultivation has been extended to non-traditional regions due to the limited scope of further expansion in traditional rubbergrowing areas in India. These areas are often confronted with various abiotic stresses, especially high and low temperatures, which cause reduction in plant growth, thereby increasing its uneconomical immaturity period. Eighteen wild Hevea accessions along with two modern clones RRII203 and PB 235 and two check clones RRIM 600 and Haiken 1 were evaluated in the early mature growth phase.The site was at Nagrakata, West Bengal, the sub-Himalayan cold-prone region of India. In Hevea, crop production is governed by two major factors, growth-vigor and production capacity. Growth-vigor is of special importance because the production of rubber is a process linked with the early growth of the plant, which results in early tappability and early economic gains. The genotypes exhibited highly significant clonal differences(P = 0.05) for all the growth traits. Tappability percentage in the seventh year, ranged from 0.33 %(AC 3074, AC 3075, AC 3293) to 89.67 %(RO 2727). The most vigorously growing accession(RO2727) reached tappabile girth early in the seventh year when the girth of plant ranged from 22.38 cm(AC 3293) to53.12 cm(RO 2727). The general mean was 43.32 cm, and the similar growth trend was exhibited by these accessions in the tenth year also. Annual girth increment(cm a-1) over3 years ranged from 1.81 cm(AC 3075) to 6.80 cm(RO2727). The mean winter girth increment(cm a-1) over4 years ranged from 0.13 cm(AC 3075) to 0.96 cm(RO2727) as compared to the check clone RRIM 600(1.11 cm)and Haiken 1(1.10 cm). Wide differences between the phenotypic coefficient of variation(50.29) and genotypic coefficient of variation(24.82) were observed for winter girth increment. Girth in the tenth year recorded the highest heritability(87 %). Girth was significantly correlated with the other growth traits. The top 30 % of the potential accessions showing high growth vigour and early tappability under cold stress were identified. These ecotypes/selections have high potential value for the development of coldtolerant clones for these regions and also in broadening the genetic base of the present-day cultivated rubber. 相似文献
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橡胶树寒害气象等级研究 总被引：4，自引：1，他引：3
用我国云南、海南、广东三省主要橡胶种植区内11个气象站建站的2008年11月至次年3月逐日气象资料以及橡胶寒害灾情史料,开展橡胶树寒害等级的研究,为规范橡胶树寒害调查、统计和评估业务提供参考。根据橡胶树寒害的特点,提出橡胶树平流型低温天气过程、辐射型低温天气过程的概念,给出了橡胶树平流型寒害、辐射型寒害和混合型寒害的明确定义,并用极端最低气温、最大降温幅度、寒害持续日数、辐射型积寒、平流型积寒和最长平流寒害过程的持续日数共6个致灾因子,构建寒害指数。依据寒害指数的大小,将橡胶树寒害分为轻度、中度、重度、特重四个等级。同时给出了橡胶树遭受不同寒害等级时可能导致的橡胶干胶减产率和橡胶树受害率的参考值。 相似文献
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Jérôme Perin Hugues Claessens Philippe Lejeune Yves Brostaux Jacques Hébert 《European Journal of Forest Research》2017,136(2):193-204
This paper presents new harmonized distance-independent individual tree basal area growth models for Norway spruce, Douglas-fir and Japanese larch in pure even-aged stands in Southern Belgium. The selected model was originally developed for Norway spruce and Douglas-fir in neighboring France. New formulations are proposed for some of the model components in order to lower the number of fitted parameters and facilitate the fitting procedure. The resulting models integrate the most recent corresponding top-height growth models and use four simple and usually collected explanatory variables: stand age, top-height, total basal area and tree girth at breast height. The modified formulations maintain similar fitting performances and make it easier to interpret the influence of the explanatory variables on tree growth. Parameters estimates were fitted on thousands of growth measurements gathered from several monitoring plots, forest management inventories and silvicultural field experiments that represent the wide range of site conditions and of forest management scenarios applied to coniferous stands in Southern Belgium. Cross-validation of the models revealed no bias and highlighted their consistent behavior over the entire range of girth at breast height, age, top-height, site index and density represented in our dataset. Combining utility and robust performances, these models represent useful forest management tools, purposely ideal for forest simulation software development. Moreover, the flexibility and generic capabilities of the model formulation should make it easily adjustable for other species in even-aged stands. 相似文献
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D. C. Lawrence 《Agroforestry Systems》1996,34(1):83-100
The goal of this study was to assess the potential of small-holder rubber cultivation in agroforestry gardens to fulfill simultaneously the goals of conservation and sustainable rural development. I examined the structure and species composition of trees in 11 rubber gardens in West Kalimantan, Indonesia, using a single 0.10 ha plot per garden. Although 41 distinct morphotypes were encountered, rubber (Hevea brasiliensis) dominated the sample of 370 trees. Richness within plots varied (3–15 morphotypes), as did the predominance of rubber (24–97% of all basal area, 24–91% of all individuals). The importance of rubber within a garden was significantly negatively correlated with the number of morphotypes present. This result suggests that tree diversity may limit potential productivity of rubber gardens. Thus, small-holders may not be willing to maintain diversity at the scale of a single garden. Although species-accumulation curves indicate that substantial tree diversity may exist across all rubber holdings, diversity is likely to be lost from the system if individual owners reduce species richness in their gardens. Rubber agroforestry as currently practiced in West Kalimantan is not an ideal model for matching rural development needs with the achievement of conservation goals. Other models, such as tengkawang- and durian-based fruit gardens, do exist in Kalimantan and elsewhere, and should be evaluated for incorporation into policy and development strategies. 相似文献
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Isarangkool Na Ayutthaya S Do FC Pannangpetch K Junjittakarn J Maeght JL Rocheteau A Cochard H 《Tree physiology》2011,31(7):751-762
Effects of soil and atmospheric drought on whole-tree transpiration (E(T)), leaf water potential (Ψ(L)) and whole-tree hydraulic conductance (K(T)) were investigated in mature rubber trees (Hevea brasiliensis, clone RRIM 600) during the full canopy stage in the rainy season in a drought-prone area of northeast Thailand. Under well-watered soil conditions, transpiration was tightly regulated in response to high evaporative demand, i.e., above reference evapotranspiration (ET(0)) ~2.2 mm day(-1) or maximum vapor pressure deficit ~1.8 kPa. When the trees experienced intermittent soil drought E(T) decreased sharply when relative extractable water in the top soil was?相似文献
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IntroduttionMongoIianoak(QucI.cIIS))I()lIg()lIt.uFiscl1.etTurcz.)standsconstitutethelargesttypeoftI1esecondarytbrestinHeilongiiangProvince-CI1ina(llu'l979).Tl1el99IstatisticsoftheAdministrativeBtIreatIofForestRe-sourcesfOrHeilongiiangProvinceindicatedanes… 相似文献
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Ciro Abbud Righi Otávio Camargo Campoe Marcos Silveira Bernardes Aureny Maria Pereira Lunz Sônia Maria Stefano Piedade Carlos Rodrigues Pereira 《Agroforestry Systems》2013,87(6):1351-1362
The coffee leaf-miner (CLM) (Leucoptera coffeella Guérin-Mèneville; Lepidoptera: Lyonetiidae), the main pest of coffee plants, occurs widely throughout the Neotropics where it has a significant, negative economic and quantitative impact on coffee production. This study was conducted in a rubber tree/coffee plant interface that was influenced by the trees to a varying degrees depending on the location of the coffee plants, i.e. from beneath the rubber trees, extending through a range of distances from the edge of the tree plantation to end in a coffee monocrop field. The most severe damage inflicted on coffee plants by the CLM (number of mined leaves) from April, which marks the start of the water deficit period, until September 2003 was in the zone close to the rubber trees, whereas the damage inflicted on plants in the monocropped field was comparable to that on coffee plants grown directly beneath the rubber trees, which received about 25–40 % of the available irradiance (Ir—available irradiation at a certain position divided by the irradiation received in full sunlight, i.e. in the monocrop). From May until July damage caused by the CLM nearly doubled in each month. In midwinter (July), the damage decreased perceptibly from the tree edge toward the open field. From September onward, with the rising air temperatures CLM damage in the coffee monocrop started to increase. Based on these results, we conclude that coffee plants grown in the full sun incurred the most damage only at the end of winter, with warming air temperatures. Coffee plants grown in shadier locations (25–40 % Ir) were less damaged by the CLM, although a higher proportion of their leaves were mined. The rubber trees probably acted as a shelter during the cold autumn and winter seasons, leading to greater CLM damage over a distance outside the rubber tree plantation that was about equal to the height of the trees. Future studies should attempt to relate leaf hydric potential to pest attack in field conditions. More rigorous measurements of shade conditions could improve our understanding of the relationship of this factor to CLM attack. 相似文献
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Luke P. Rapley Brad M. Potts Michael Battaglia Vinu S. Patel Geoff R. Allen 《Forest Ecology and Management》2009
Insect damage to production forests has the potential to reduce financial returns by retarding tree growth and causing mortality, however, long-term realised quantification of these losses is rare. In order to help elucidate economic damage thresholds for making spray decisions we capitalised on a natural outbreak of autumn gum moth, Mnesampela privata, in a 2-year-old Eucalyptus nitens plantation. Following the partial chemical control of this insect outbreak we measured the tree growth variables diameter at breast height over bark and height of five differing tree defoliation classes for 75 months following tree damage. At the end of this period a threshold model was fitted to describe the relationship between tree defoliation and realised tree wood volumes. The model revealed that realised stand wood volume was not significantly affected up until defoliation exceeded 60% and then declined sharply after this defoliation level was reached. Further support for this defoliation threshold was evident from multiple comparisons among defoliation classes that showed 50% defoliated trees did not have significantly different wood volume compared to more lightly defoliated trees, but did have significantly greater wood volume compared to trees that were 72% or more defoliated. To determine if the realised differences in wood volume resulted in differences in yield over a plantation rotation the E. nitens growth model NITGRO was used to on-grow trees to age 15 years for a ‘best case’ (type 1 growth response, constant growth rates from last inventory until harvest) and ‘worst case’ (type 2 growth response, divergent growth rates from last inventory until harvest) scenario. The threshold model was then fitted to the outcomes of both scenarios and the economic consequences of defoliation were clearly dependent on the growth function assumed. 相似文献
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桂西南米老排人工林单株生物量回归模型 总被引：1，自引：0，他引：1
通过对桂西南大青山林区28a生米老排(Mytilaria laosensis)人工林林分进行每木检尺和生物量的测定,建立了米老排各器官生物量与胸径、树高和胸径平方乘树高(D2 H)的相关关系;分别选用幂函数等5种模型,用回归分析方法对米老排人工林单株生物量模型进行了拟合。结果表明:树叶和树根生物量分别与胸径和树高的相关关系最显著,而树干、树枝、树皮和全株的生物量都与D2 H的相关关系最为显著。胸径、树高和D2 H与各器官生物量拟合的模型中,全株、树干和树皮的拟合效果最好,树叶和树根的拟合效果中等,树枝的拟合效果较差。除树皮外,各器官均以幂指数模型的拟合效果最好。 相似文献
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橡胶是四大工业原料之一 ,在交通、军用工业中尤为重要。其中天然橡胶的主要来源是巴西橡胶树 (H evea brasiliensis Muell. Arg.) ,它在我国南方热带地区广为栽培 ,是重要的经济树种和用材树种 ,因而是工业与民用的重要资源。已有研究证实 :橡胶树根系可以形成 AM菌根 (arbuscular mycorrhiza)。AM菌根是广泛分布的一类内生菌根 ,能够促进宿主植物吸收土壤中的养分 ,增强宿主的抗逆性 ,有利于植物生长。近 30 a来 ,国外一些学者对橡胶树菌根真菌的资源与分布 ,菌根真菌对苗木营养和生长效应以及提高苗木抗逆性方面进行了研究。而国内尚… 相似文献
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Four alternative functions are used for fitting tree height and diameter growth models for mongolian oak. (Quercus mongolica Fisch. et Turcz.). The data set includes 1250 random trees and 755 dominant trees coming from 510 temporary plots. The resultsshow
that the Richards function is the best model for predicting height. diameter at breast height (DBH) and dominant height from
age. The average growth curve of dominant height is used as a guide curve for the construction of a site index table which
is partially validated using an independent data set. The Mitscherlich function is the best model for estimating height and
dominant height from DBH.
(Responsible Editor: Chai Ruihai) 相似文献
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We compared the growth of trees produced by micropropagation from nodal stem sections or callus tissue of a 20-year-old silver birch (Betula pendula Roth) tree with that of seedlings; growth was monitored for 17 months in pots followed by six years in the field. Micropropagated trees from both nodal stem sections and callus tissue grew at a similar rate to seedling trees and no obvious mutant types were observed. However, micropropagated trees were more uniform in height and trunk girth than seedling trees and more than 80% flowered within three years of field planting, whereas only 39% of seedling trees flowered within this time. Micropropagated trees had less bark fissuring, a mature characteristic, than seedling trees. 相似文献
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An annual individual tree survival and growth model was developed for pure even-aged stands of maritime pine in Portugal, using a large data set containing irregularly time-spaced measurements and considering thinning effects. The model is distance-independent and is based on a function for diameter growth, a function for height growth and a survival function. Two approaches are compared for modeling annual tree growth. The first approach directly estimates a future diameter or height using well-known growth functions formulated in difference form. The second approach estimates diameter or height using a function in differential form estimating the increment over a year period. In both approaches, the function parameters were related to tree and stand variables reflecting the competition status of the tree as well as of a thinning response factor. Variable growth and survival rates were assumed in the modeling approaches. An iterative method was used to continuously update tree and stand attributes using a cut-off to convert the survival probability for a living or a dead tree. The individual tree diameter growth model and the survival probability model were fitted simultaneously using seemingly unrelated regression (SUR). Parameters of the height function were obtained separately as the number of observations for height was much lower than the number of observations for diameter, which may affect the statistical inference and the estimation of contemporaneous cross-equation error correlation inherent to the system of equations. PRESS residuals were used to evaluate the predictive performance of the diameter and the height growth functions. Additional statistics based in the log likelihood function and also in the survival probability were computed to evaluate the survival function. The second modeling approach, which integrates components of growth expansion and decline, performed slightly better than the first approach. A variable accounting for the thinning response that was tested proved to be significant for predicting diameter growth, even if the model already included competition-related explanatory variables, namely the basal area of trees larger than the subject tree. However, this thinning response factor was not significant for predicting height growth. 相似文献