High Wood Density Research Articles

Acacia mearnsii industry overview: current status, key research and development issues

Acacia mearnsii De Wild (black wattle) is an important plantation species for tannin production and woodchip exports in South Africa and Brazil. This study provides an updated overview of the black wattle industries in both countries, including planted areas and land ownership, silviculture and management, bark extract production, woodchip exports, as well as key research and development issues. The current total planted area to black wattle is 110 000 ha in South Africa and c. 170 000 ha in Brazil. In both countries black wattle is mainly cultivated by farmers (c. 76–78% of the total area). Due to the high prices fetched by the wattle woodchips in the international market, black wattle is a profitable crop. In South Africa, the timber provides 85% of the revenue and the bark the other 15%, and thus the commercial emphasis has shifted from bark to timber. At present the only significant secondary products are charcoal and firewood. Acacia mearnsii bark tannins are used in the leather industry, adhesives for wood composites, water flocculants and specialty products for the chemical, food and beverage industries. The world demand for vegetable tannins has remained unchanged over the past two decades due to intense competition from synthetic tannins. South Africa produces about 45 000 t of bark extract annually, whereas Brazil produces 30 000–40 000 t. The annual value of A. mearnsii extract from South Africa and Brazil is about US$100 million. The total wattle woodchip exports from South Africa and Brazil in 2013 was 800 000 bone dry metric tonnes (BDMT) and 570 000 BDMT, respectively, with an estimated value of US$208 million. Acacia mearnsii offers important economic advantages for pulp production (higher wood density and pulp yield, which translate into higher digester productivity and factory output), and is highly suitable for hardwood bleached kraft pulping, dissolving and semi-chemical pulps. These factors make A. mearnsii a sought-after species and have ensured a sustained demand for wattle woodchips in the Japanese market, and today continue to attract new customers in emerging markets (China and India). The most important challenges for the black wattle industry in South Africa are (1) to maintain the wattle land base and improve productivity from the existing resource and (2) considering that black wattle is a highly labour-intensive crop and the recent increases in labour costs, it is necessary to revisit current silviculture practices from a costs–yield perspective and to develop mechanised harvesting/bark stripping systems. The Brazilian wattle industry faces important challenges in silviculture, tree improvement, and pests and diseases, which require further research and collaboration between the few players involved. It is important for both Brazil and South Africa to develop domestic markets for wattle solid wood as additional sources of income for the many farmers growing wattle.

水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响 DOI: 10.5846/stxb201306101572 作者: 作者单位: 中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;哈佛大学,中国科学院西双版纳热带植物园,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院哀牢山亚热带森林生态系统研究站研究基金 The influence of changes in water availability on seedling mortality of a subtropical evergreen broadleaf forest on Ailao Mountain Author: Affiliation: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences,Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Harvard University,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨环境水分条件变化对亚热带森林林下乔木幼苗动态的影响,以及木材密度和幼苗在干旱中死亡率的关系,研究了哀牢山常绿阔叶林2005-2011年的总体和主要树种幼苗(黄心树、多果新木姜子、多花山矾、鸭公树和大花八角)的死亡率,并分析了幼苗死亡率和旱季幼苗根系所在土层土壤质量含水量、旱季降水量、旱季降水日数以及木材密度的关系。结果表明:1)幼苗死亡率与旱季降水日数、旱季浅层土壤平均质量含水量有显著的负相关关系,和旱季降水量无显著相关性;2)总幼苗及5种乔木幼苗的死亡率均在2010年(西南干旱)达到有观测以来最高,是2009年的2-10倍,其中多花山矾、黄心树幼苗的死亡率最高,大花八角幼苗的死亡率最低;3)在种间,幼苗2010年干旱中的死亡率和木材密度显著正相关,即木材密度较大的物种幼苗死亡率更高。研究表明林下幼苗由于根系较浅,对降雨变化较为敏感,因而受到了这次干旱的较大影响。由于木材密度较低的树种在干旱中有较低的死亡率,干旱频度和强度的增加可能使低木材密度幼苗的丰富度增加,森林的组成也将受到影响。 Abstract:In order to understand the influence of changes in water availability on the seedling dynamics of subtropical forests and the relationship between wood density and seedling mortality during a prolonged drought period, we studied seedling mortality patterns across all species and of 5 common tree species from an evergreen broadleaf forest on Ailao Mountain, southwest (SW) China from 2005 to 2011. The five tree species studied were Machilus bombycina, Neolitsea polycarpa, Symplocos ramosissima, Neolitsea chuii, and Illicium macranthum. The relationships between seedling mortality and rainy days, rainfall, soil water mass content (0-20 cm) during the dry season, and wood density were also analyzed. Our results showed that 1) Seedling mortality was negatively correlated with number of rainy days in the dry season and dry season soil water mass content, but not with total dry season rainfall; 2) The seedling mortalities of all species as a whole and of each of the 5 species studied reached a historical maximum in the 2010 SW China extreme drought, which were 2 to 10 times more intense than for 2009 (Machilus bombycina and Symplocos ramosissima had the highest seedling mortalities while Illicium macranthum had the lowest in 2010); 3) Across species, the seedling mortality in the 2010 drought was positively correlated with species-specific wood densities; species with higher wood densities had higher seedling mortalities. Previous studies have shown that trees in this forest did not experience severe drought stress during the 2010 SW China drought. However, the present study suggests that the seedlings were severely influenced by the rainfall anomaly during the 2010 dry season, probably owing to their shallow rooting depths and consequently high sensitivities to changes in rainfall. Additionally, because of the lower seedling mortalities in lower wood density species, the potential increase in drought frequency and severity in the future may increase the relative abundance of low wood density species, which may potentially lead to changes in forest species composition. 参考文献 相似文献 引证文献

Characterizing compression wood formed in radiata pine branches

The formation of reaction wood is an adaptive feature of trees in response to various mechanical forces. In gymnosperms, reaction wood consists of compression wood (CW) and opposite wood (OW) that are formed on the underside and upperside of bent trunks and branches. Although reaction wood formed in bent trunks has been extensively investigated, relatively little has been reported from conifer branches. In this study SilviScan® technology was used to characterize radiata pine branches at high resolution. Compared to OW formed in the branches, CW showed greater growth, darker colour, thicker tracheid walls, higher coarseness, larger microfibril angle (MFA), higher wood density, lower extensional stiffness and smaller internal specific surface area. However, tracheids of CW were similar to those of OW in their radial and tangential diameters. These results indicated that gravity influenced tracheid cell division and secondary wall formation but had limited impact on primary wall expansion. Furthermore, seasonal patterns of CW formation were not observed in the branches from cambial age 4 while earlywood and latewood were clearly separated in all rings of OW. The marked change of MFA during reaction wood formation suggested that branches could be ideal materials for further study of cellulose microfibril orientation.

Wood density: A tool to find complementary species for the design of mixed species plantations

The successful establishment and growth of mixed-species forest plantations requires that complementary or facilitatory species be identified. This can be difficult in many tropical areas because the growth characteristics of endemic species are often unknown, particularly when grown at potentially higher densities in plantations than in natural forests. Here, we investigate whether wood density is a useful and readily accessible trait for choosing complementary species for mixed species plantations. Wood density represents the carbon investment per unit volume of stem with a trade-off generally found between fast (low wood density) and slow (high wood density) growing species. To do this, we use data collected from 18 highly diverse mixed species plantations (4–23 mostly native species) aged from 6 to 11years at the time of data collection located on Leyte Island, Philippines. We found significant negative correlations between wood densities and the height of the most abundant species, as well as with measures of overall stand growth and tree diameter size distribution.Not only do species with denser woods have slower growth rates, but also mixed-species plantations with higher average wood density and higher stem density were also less productive, at least in these young plantations. Similarly, stands with a high diversity in wood densities were less productive. There is growing interest in making greater use of native multi-species mixtures in smallholder and community planting programs in the tropics, and our results show databases of wood density values may help improve their design. In the early development stages of plantations, canopy closure and rapid height growth are usually key silvicultural targets, and wood density values can predict the rapid height development of species. If plantations are being grown for the livelihood of small landholders then the best target is to choose some species with different wood densities. This allows an early harvest of low-wood density species for early income, and will also reduce competition for slower growing trees with higher wood densities for later income generation.

Forest production dynamics along a wood density spectrum in eastern US forests

Key message Emerging plant economics spectrum theories were confirmed across temperate forest sys- tems of the eastern US where the use of a forest stand's mean wood density elucidated forest volume and bio- mass production dynamics integrating aspects of cli- mate, tree mortality/growth, and rates of site occupancy. Abstract As a tree's functional trait of wood density has been used to refine models of tree competition, it may also aid in evaluating hypotheses of forest production such as declining growth and mortality across a spectrum of increasing wood density. The goal of this study was to examine trends in aboveground live tree production as related to mean wood density using a region-wide repeated forest inventory across eastern US forests. Using quantile regression, the 90th percentile of volume and biomass accretion was negatively related to the mean wood density of a stand's constituent tree species. This relationship was strongest on forest sites with the highest number of growing season degree days, as growing season length influences the rates of stand development. For these sites, variations in volume and biomass accretion were most pronounced in stands with low mean tree wood density, which also demonstrated the highest rates of site occu- pancy and mortality. This study confirmed aspects of the emerging theory of ''fast-slow'' plant economics spec- trums across temperate forest ecosystems. Stands with relatively low wood density appear to occupy sites more rapidly leading to a concomitantly higher rate of tree mortality, but with less biomass accretion relative to vol- ume due to allocating biomass or carbon to a greater tree volume. In contrast, stands with higher wood density exhibited slower site occupancy due to high wood density construction costs, but with increased biomass relative to volume accretion. These findings highlight the potential application of the plant economics spectrum theory in refining our understanding of general patterns of forest stand production, the role of plant traits in forest man- agement, and knowledge gaps such a shifts in tree allom- etry during stand development.

Resource economics and coordination among above- and below-ground functional traits of three dominant shrubs from the Chilean coastal desert

Aims Plant functional traits determine how plants respond to environmental factors and influence ecosystem processes. Among them, root traits and analyses of relations between above and below-ground traits in natural communities are scarce. We characterized a set of above- and below-ground traits of three dominant shrub species in a semiarid shrub-steppe that had contrasting leaf phenological habits (deciduous, semideciduous and evergreen). We analysed if there was coordination among above- and below-ground resource economics patterns: i.e. patterns of biomass allocation, construction costs and lifespan. Important Findings Above- and below-ground traits and their resource economics relations pointed to species-specific functional strategies to cope with drought and poor soils and to a species ranking of fast to slow whole-plant strategies in terms of resource uptake, biomass construction costs and turnover. The deciduous shrub, Proustia cuneifolia, had relatively deep and even distribution of roots, and high proportion of short-lived tissues of low C construction costs: it had high fine to coarse root and high leaf-to-stem biomass ratios, high specific leaf area (SLA), and stems of low wood density. This strategy allows Proustia to maximize and coordinate above- and belowground resources uptake as long as the most limiting factor (water) is available, but at the cost of having relative high plant biomass turnover. The evergreen Porlieria chilensis, instead, displayed a more conservative and slow strategy in terms of resource economics. It had ~80% of the roots in the 40 cm topsoil profile, low proportion of fine compared with coarse roots and low leaf-to-stem ratios, low SLA and stems of high wood density, i.e. it invested in C costly tissues that, overall, persist longer but probably at the cost of having lower plant resource uptake rates. Traits in the semideciduous Adesmia bedwellii were in between these two functional extremes. Our results revealed high functional diversity and aboveand below-ground complementarity in resource economics among these three codominant species in the Chilean coastal desert.

Assessment of fuelwood based on community preference and wood constituent properties of tree species in Mizoram, north-east India

This paper analyses the community choice of fuelwood species among 30 selected tree species in Mizoram state, north-east India. The analysis was based on 12 community selected criteria, including availability of the species and 11 fuelwood quality criteria. The wood constituent properties, including the fuelwood value index (FVI), were also assessed for the 30 tree species. The most preferred species were Quercus spp. Due to its low availability in the area, Mesua ferrea, which was ranked 12th by the community, although it showed the highest wood density (0.58 g/cm2). Similarly, Anogeissus acuminata ranked only 15th, although it had the highest FVI. Quercus pachyphylla, Quercus polystachya, Quercus xylocarpa, Quercus helferiana, Quercus serrata, Vitex peduncularis and M. ferrea were found to be highly desirable fuelwood species based on their high FVI. These species should therefore be considered as good candidates for a domestication and plantation programme in order to relieve pressure on natural forests.

Wood nitrogen concentrations in tropical trees: phylogenetic patterns and ecological correlates.

In tropical and temperate trees, wood chemical traits are hypothesized to covary with species' life-history strategy along a 'wood economics spectrum' (WES), but evidence supporting these expected patterns remains scarce. Due to its role in nutrient storage, we hypothesize that wood nitrogen (N) concentration will covary along the WES, being higher in slow-growing species with high wood density (WD), and lower in fast-growing species with low WD. In order to test this hypothesis we quantified wood N concentrations in 59 Panamanian hardwood species, and used this dataset to examine ecological correlates and phylogenetic patterns of wood N. Wood N varied > 14-fold among species between 0.04 and 0.59%; closely related species were more similar in wood N than expected by chance. Wood N was positively correlated with WD, and negatively correlated with log-transformed relative growth rates, although these relationships were relatively weak. We found evidence for co-evolution between wood N and both WD and log-transformed mortality rates. Our study provides evidence that wood N covaries with tree life-history parameters, and that these patterns consistently co-evolve in tropical hardwoods. These results provide some support for the hypothesized WES, and suggest that wood is an increasingly important N pool through tropical forest succession.

Functional groups of woody species in semi‐arid regions at low latitudes

AbstractIn seasonally dry environments, woody species have different survival strategies. However, little is known about how environmental variables affect the phenology and water dynamics of these species. We aim to understand which variables initiate the vegetative phenophases of species in a tropical semiarid climate at 3°S latitude, where variation in photoperiod is minimal and rainfall is seasonal. We hypothesize that groups of species with similar vegetative phenologies, under similar conditions, are functionally similar in terms of water storage and use. We analyse the relationship between functional characteristics related to the acquisition and utilization of water, such as wood density, water storage capacity, water potential and vegetative phenology. The attributes were ordered by multidimensional scaling, and a multiple response permutation procedure was used to test consistency of the groups. Canonical correspondence analysis and Mantel tests were used to evaluate the phenophase response to environmental variables. We found four functional groups: (i) deciduous low wood density, which lose 75% of their leaves one month before the end of the rains; (ii) evergreen high wood density; (iii) early deciduous high wood density, which lose 75% of their leaves one month after the end of the rains; and (iv) late deciduous high wood density, which lose 75% of their leaves two months after the end of the rains. As expected, the vegetative phenodynamics of the deciduous high wood density group were mainly influenced by water availability. The evergreens did not show a correlation with rainfall. Only leaf shedding of the late deciduous, and the vegetative phenophases of the evergreens, responded to an increase in temperature and photoperiod. Bud‐break responded to increased photoperiod and soil humidity in the deciduous low wood density group. The foliar periodicity groups can be explained by the presence of species that differ mainly in their mechanisms of water acquisition and use.

Mixed-forest species establishment in a monodominant forest in central Africa: implications for tropical forest invasibility.

BackgroundTraits of non-dominant mixed-forest tree species and their synergies for successful co-occurrence in monodominant Gilbertiodendron dewevrei forest have not yet been investigated. Here we compared the tree species diversity of the monodominant forest with its adjacent mixed forest and then determined which fitness proxies and life history traits of the mixed-forest tree species were most associated with successful co-existence in the monodominant forest.Methodology/Principal FindingsWe sampled all trees (diameter in breast height [dbh]≥10 cm) within 6×1 ha topographically homogenous areas of intact central African forest in SE Cameroon, three independent patches of G. dewevrei-dominated forest and three adjacent areas (450–800 m apart). Monodominant G. dewevrei forest had lower sample-controlled species richness, species density and population density than its adjacent mixed forest in terms of stems with dbh≥10 cm. Analysis of a suite of population-level characteristics, such as relative abundance and geographical distribution, and traits such as wood density, height, diameter at breast height, fruit/seed dispersal mechanism and light requirement–revealed after controlling for phylogeny, species that co-occur with G. dewevrei tend to have higher abundance in adjacent mixed forest, higher wood density and a lower light requirement.Conclusions/SignificanceOur results suggest that certain traits (wood density and light requirement) and population-level characteristics (relative abundance) may increase the invasibility of a tree species into a tropical closed-canopy system. Such knowledge may assist in the pre-emptive identification of invasive tree species.

Evaluating the tropical forest carbon sink

Evaluating the tropical forest carbon sink

Growth and wood properties of genetically improved loblolly pine: propagation type comparison and genetic parameters

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties.

Phenology of Woody Species: a Review

An attempt has been made to synthesize a brief account on research advances on various phases of phenology. Climate has positive impact on the timing of phenology; cold-air drainage may influence the start of leaf growth, however leaf phenology in tropical evergreen forests is not determined by the seasonality of precipitation. Climate warming in late winter and spring may enhance sensitivity of the growing season’s spatial response due to the relationship of beginning date to temperature. Elevated temperature strongly influences greater in C3 plants than in C4 plants but the disadvantages of warming may be considerably attenuated by elevated CO2, especially for C3 grasses. Species with high wood densities can able to store only limited quantities of water in their trunks; leaf fall in these species occurred during the dry season. Flowering phenology may be changing faster and precipitation may play a more important role in semi-arid grasslands than in humid-temperate systems. Peak flowering and fruiting are dependent on seasons for both endemic and non-endemic species. Population sensitivity to global warming might be stable for a given species, in spite of its possible local adaptation. It might be possible for ecologists to establish comprehensive networks for long-term monitoring of potential photosynthetic capacity from regional to global scales by linking satellite-based programme. Use of satellite-derived metrics,such as VARI, may be used for evaluating the spatial patterns and temporal dynamics of species composition across broad geographic regions.

Densidade da madeira de árvores em savanas do norte da Amazônia brasileira

Densidade da madeira (DM) é uma variável importante para estimativas de estoques de carbono arbóreo em ecossistemas terrestres. Este tema é pobremente investigado em áreas de savana da Amazônia brasileira. O objetivo deste estudo foi investigar a DM das oito principais espécies arbóreas que ocorrem na savana aberta de Roraima, a maior área de savana do norte do bioma Amazônia. Foram verificadas as variações na DM em função da espécie e dos diferentes diâmetros observados ao longo da dimensão vertical de 75 indivíduos amostrados em seis sítios de coleta. Foi utilizado o método direto para obtenção de peças de madeira do fuste e da copa. Os resultados indicaram discrepância significativa interespecífica, sendo Roupala montana Aubl. a espécie de maior DM média (0,674 g cm-3). Foi detectado que existe variação significativa da DM entre as peças do fuste e da copa, independente da espécie e do sítio de coleta. A densidade da madeira de peças da copa com diâmetro entre 5 e 10 cm pode ser utilizada como preditora da DM média do indivíduo arbóreo. Nós concluimos que a DM das oito espécies arbóreas investigadas possui variabilidade interespecífica, com discrepâncias entre a DM do fuste e das partes lenhosas da copa. As distinções aqui detectadas devem ser considerados como uma importante ferramenta para melhorar as estimativas de estoque de carbono em áreas de savanas na Amazônia.

Differentiation in architectural properties and functional traits of forest-floor saplings among heath, peat swamp, and mixed dipterocarp forests

There are physiognomically distinctive forest types in lowland tropics reflecting variation in edaphic conditions. Tree saplings that contribute to forest regeneration are expected to show morphological properties in response to forest environment. However, it remains unknown how sapling properties are similar or different across forest types. We examined architectural and functional traits of forest floor saplings across heath, peat swamp, and mixed dipterocarp forests that characterize lowland forests in Kalimantan, Indonesia. Saplings (150-310 cm tall) of 41 species, which represent each forest type, were selected under the canopy of developed forest stands. Among these, we chose one species found in all forest types and two species in heath and peat swamp forests. Significant differences in crown allometries were found across forest types and across species. Saplings in mixed dipterocarp forest had thicker trunk and wider crown at the same sapling height compared to other forests and they had higher specific leaf area, higher mass-based leaf nitrogen content and lower wood density. Heath forest saplings showed lowest leaf nitrogen content and highest wood density. Species with across forest-type distribution showed intra-specific variation in sapling traits, and which was similar to the difference among forest types. We conclude that saplings show morphological response to nutritional and water conditions that characterize forest types.

Development, validation, and application of a model of intra- and inter-tree variability of wood density for lodgepole pine in western Canada

Wood density is an important characteristic for evaluating wood quality and estimating tree biomass. The ring-level focus of most density models requires inputs and produces predictions at a scale at which industry does not currently operate. Our objective was to develop a model at a scale intermediate between ring and tree levels that would capture the significant, operationally relevant variability that exists within lodgepole pine (Pinus contorta Douglas ex Loudon) trees. We developed a model for estimating mean wood density for groups of five growth rings using a nonlinear mixed-effects modelling approach. The data were collected from six long-term silviculture research trials in Alberta and British Columbia, Canada. An independent data set from west-central Alberta was used for validation. Our results indicated that the density variation pattern can be reproduced using ring width and distance from pith as fixed effects and including site- and tree-level attributes as random effects. The stochastic variation of density among trees was large. Based on the estimated tree-level random effect distribution, prediction bands conditional on simulated random effects were proposed to assess intertree variability of density within a site. Estimation of site-level random effects may reduce bias for sites with low or high wood density.

Towards an advanced assessment of the hydrological vulnerability of forests to climate change‐induced drought

Towards an advanced assessment of the hydrological vulnerability of forests to climate change‐induced drought

Numerical simulation of the glowing combustion of moist wood by means of a front‐based model

ABSTRACTA model is presented for the glowing combustion of thick moist wood samples exposed to fire‐level heat fluxes. It includes the description of all the relevant heat and mass transfer phenomena and assumes that the thermally controlled drying, the finite‐rate kinetics pyrolysis, and the mixed kinetic‐diffusive controlled combustion take place at infinitely thin fronts. The solution, based on the integral method, shows that apart from short initial and final transients, an ablation regime is established given high external heat fluxes and/or high moisture contents, high wood density and thermal conductivity, and low char density. Drying, pyrolysis, and combustion take place simultaneously along a constant‐thickness layer that propagates at a constant rate (the same for the three fronts) towards the cold sample side. Good quantitative agreement is obtained between model predictions and measurements. Copyright © 2013 John Wiley & Sons, Ltd.

THE POTENTIAL OF RUBBER AGROFORESTRY FOR RATTAN (Calamus sp) CULTIVATION IN KATINGAN REGENCY: DIVERSITY OF CLIMBING TREES FOR RATTAN

This research aims to evaluate the diversity of climbing trees for rattan in agroforestry system. The result of this research is expected to be applied as the standard to improve the management in rattan agroforestry. The research was conducted from June to December 2011 in three different villages: Kalemei, Hiran and Liting in Katingan regency, Central Kalimantan. The data were collected via purposive sampling in two different types of land cover i.e rubber agroforestry (RA) and secondary forest (SF), each of system had 6 plots and 18 sub-plots of experiment. The evaluation of species diversity was performed by measuring species richness, Importance Value Index, and Diversity Index. Statistic model was constructed by employing the approach in multivariate analysis and cluster analysis. The results indicated that SF had higher species diversity (3.02 – 3.45). The diversity level of RA was higher in Hiran village (3.96), than in the other two villages (<3.0). Habitat similarity was characterised by the similar composition and structure of vegetation of both SF and RA in Hiran and Kalemei, but not in Liting. The potential of supporting trees for rattan in RA is rather high as shown by high species density and the presence of trees with high wood density (0.75-0.9g cm -3 ) to extremely high (>0.9g cm -3 ) as it found in SF. Keywords : Rattan, rubber agroforestry, climbing trees for rattan, secondary forest

Production of a new generation of seeds through the use of somatic clones in controlled crosses of black spruce (Picea mariana)

To assess the potential to integrate somatic clones (SC) of desired characteristics in production of high genetic quality seed, controlled crosses between different SCs of black spruce (Picea mariana (Mill) B.S.P.) were used to assess their suitability for the production of viable pollen, cones, seeds and seedlings. These SC produced male and female strobili at an early stage. Pollen, cones and seeds produced were characterized (mass, size, germination); their characteristics were similar to those produced by trees in natural forests or seed orchards. A maternal effect was demonstrated for the cone size and seed mass. Although seeds had excellent germination rates, the somatic biparental crosses were divided into three distinct groups with different germination curves using the Weibull function. Seeds from controlled crosses between different SC enabled the production of high morpho-physiological quality seedlings in a forest nursery. Using black spruce as a model, we showed, for the first time, that SC can be used as seed producers. These encouraging results open new perspectives on the tangible integration of somatic embryogenesis (SE) in the chain of seed, vegetative propagation (cuttings and SE) and production of plants for high productivity plantations. Controlled crosses can be made between SC with the desired characteristics (fewer large branches, fewer nodes, good growth, high wood density, performance, improved yield, etc.), vegetative propagules produced and deployed to clonal tests. After elimination of the worst performing SC, clonal tests can be converted into seed orchards that produce a new generation of seeds of high genetic quality. This will allow the rapid introduction of new materials in elite breeding programs of forest species.