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1.
Realized genetic gains brought by the first-generation tree improvement of Acacia mangium were evaluated by analyzing the 1-year growth performance of growth (height, dbh) and form (stem straightness, multi-stem) traits using data collected from three second-generation orchards: groups B, C, and D. Each orchard was composed of improved families derived from open-pollinated seed of plus trees selected from the first-generation seed orchards and newly added unimproved families collected from the same geographic region. The number of improved families and that of the unimproved in each orchard were 31 and 23 for group B, 28 and 39 for group C, and 24 and 30 for group D. Gains were calculated as percentage increase of improved families over unimproved ones. Improved families performed better than unimproved ones in 11 out of 12 comparison cases: four traits each in the three orchards. Averages of the realized genetic gain across the three seedling seed orchards were 3.1%, 5.2%, 4.3%, and 0.5% for height, dbh, stem straightness, and multi-stem, respectively. Except for multi-stem, the performances of improved families were significantly better than those of unimproved families in all the three orchards for dbh and in two out of three orchards for height and stem straightness. 相似文献
2.
The time trend of genetic parameters related to diameter growth was investigated using data at ages from 1 to 6 years to determine
the optimum age for selection in four seedling seed orchards of Eucalyptus pellita in South Kalimantan and Riau (Sumatra), Indonesia. The seed orchards at each location were from three geographically distinct
provenances from Papua New Guinea. The pooled sum of squares and sum of cross products derived from an analysis of variance
of growth of the three provenance populations were used to estimate genetic parameters at each location. Because the genetic
parameters at rotation age, 8 years in this study, were not available, they were estimated using functions derived from their
time trends. Phenotypic variances and genetic variances calculated at each age were converted to the corresponding square
roots, and then analyzed by the linear regression using means as independent variables. The trend of juvenile–mature correlation
was fitted by a modified Richards function with the ratio of the older diameter mean to the juvenile diameter as an independent
variable. Early selection always resulted in more genetic gain per year than selection at rotation age, and the optimum age
for selection, where genetic gain per year was maximized, was found to be 4 and 5 years in the two locations. 相似文献
3.
Trend of within-plot selection practiced in two seedling seed orchards ofAcacia mangium in Indonesia
A trend of within-plot selection was examined by applying a retrospective selection index to the results of the selection
in two seedling seed orchards ofA. mangium at South Kalimantan in Indonesia. The orchards were established in randomized complete block design with ten replications
of four tree row plots. Within-plot selections were conducted twice with around 50% of selection intensity in those orchards:
at 22 months and at 51 months after planting, then the results were analyzed with the data on volume, stem form and bole length
measured before each selection. Bole length was found to be the highest priority trait throughout the two stages of selection
in both orchards. Growth expressed by volume was also an important criterion at the first within-plot selection, while the
priority was not obvious at the second selection. Expected gains by within-plot selection were generally small, although predicted
gains were positive on all of the three traits at each stage of selection.
The seedling seed orchards analyzed in this study were established under a technical cooperation project between JICA (Japan
International Cooperation Agency) and Ministry of Forestry in Indonesia in collaboration with Inhutani 3. 相似文献
4.
Variation of traits that include height, diameter at breast height (DBH), stem volume, crown width, straightness, wood basic
density, tracheid length and width of open-pollinated progenies from clonal seed orchard of Pinus massoniana was analyzed. Differences in traits such as growth, tree form and wood quality among families was significant, which indicated
that the improvement potential was notable. Heritability of height and wood basic density reached 0.691 and 0.640, respectively.
According to a correlation analysis between traits, stem straightness could be improved indirectly when growth traits are
improved; growth traits were significantly correlated with wood basic density; and wood basic density was not significantly
correlated with length and width of the tracheid. Under the selection ratio of 10%, genetic gains were 19.74% and 19.32% respectively,
and selected families from the progeny test stands at the age of five years and eight years were the same. Genetic correlation
of height, DBH and stem volume was also significant at the level of 0.01. These show that selection of the short rotation
of P. massoniana for pulp and paper use would be efficient for five-year-old trees. According to the comparison of the heritability of all
the traits and taking into account the result of canonical correlation analysis, height could be considered as the most important
index for selection. Given wood quality of all the families, and flowering and fruit settings of the clones in a seed orchard,
twelve fine families were selected at 10% selection ratio of height growth and stem volume.
Translated from Scientia Silvae Sinicae, 2005, 41(6): 43–49 [译自: 林业科学] 相似文献
5.
油松高世代种子园营建技术 总被引：1，自引：0，他引：1
通过对3批142个油松优树半同胞子代进行测定,选出36个优良家系,树高、胸径、材积平均增产15.4%、26.9%、73.3%,遗传增益分别为8.2%、8.5%、22.2%;再从优良家系内选择263个优良单株,树高、胸径、材积平均增产27.2%、41.1%、125.9%,预期遗传增益分别为13.3%、11.7%、37.2%;用选出的优良单株营建高世代无性系种子园,并提出了高世代种子园建立技术和种子高产关键技术. 相似文献
6.
The preliminary assessment of progeny test in a seed orchard of Eucalyptus globulus Labill.ssp.globulus at Yipinglang State Farm of Yunnan Province in China was conducted.The trial was composed of 21 replications,with 2 trees on each plot,15 plots in each incomplete block,and 18 incomplete blocks in each replication,laid out in a α-design of 270 open-pollinated families.The families were of three categories (natural populations,local land race and seed orchard).They were further subdivided into 11 regions.The data from an assessment of growth,stem form and other characteristics of the young trees after being planted 2 years were analyzed.Results are as follows:the different categories differed significantly in their growth,with the families from seed orchards being the best.Regions also differed significantly in their growth.The families from the regions of Westem Victoria,Eastern Victoria and all three seed orchards were better than others.The tamilies from Yunnan had the best frost tolerant and its survival was the highest.For growth,stem form and fungal tolerance,the families from Yunnan were similar to that from Southern Tasmania and Eastem Tasmania.Two-tree plots were strongly recommended over singletree plot designs for large-scale progeny trials. 相似文献
7.
Increases in stand volume with some currently introduced provenances of Acacia mangium: Papua New Guinea (PNG) and Far North Queensland (FNQ), were projected based on their superiorities in 3-year height growth
in seedling seed orchards using the growth model developed for unthinned plantation for pulp and paper production in South
Sumatra, Indonesia. The height growth of these provenances was better than that of the local selections from Subanjeriji by
10%–15% at 3 years old and these percentage superiorities would be expected to remain at around 9%–14% until the 8-year rotation.
This amount of increase would result in a 7%–10% increase in basal area and hence it would produce a 17%–26% increase in stand
volume at rotation age when compared with the Subanjeriji seed source that was being widely used for the plantation establishment
of A. mangium in Indonesia.
Received: July 24, 2002 / Accepted: December 3, 2002
Acknowledgments The authors thank Mr. Hardjono, the director of plantation establishment at PT Musi Hutan Persada for his permission to use
data of permanent plots for the growth modeling of A. mangium. The authors are grateful to the staff at PT Musi Hutan Persada, Research and Development Center for Biotechnology and Forest
Tree Improvement, Japan International Cooperation Agency for their implementations of the study. Our thanks are also due to
Dr. Yoshida, associate professor at Kyushu University, for his advice on developing the growth modeling work.
Correspondence to:S. Kurinobu 相似文献
8.
The effects of nutritional treatments and the flowering promoter Paclobutrazol™ on tree growth and fertility were studied
in unpedigreed seedling seed orchards (SSOs) of Eucalyptus camaldulensis and E. tereticornis at two locations in southern India. At Pudukkottai, a semi-arid site in Tamil Nadu State, five treatments were applied: (1)
untreated control, (2) nitrogen (two doses of urea at 217 g N/tree), (3) nitrogen plus phosphorus (two doses of 312 g single
superphosphate), potassium (two doses of 83 g muriate of potash) and trace elements (two doses of 10 g sodium borate and 25 g
zinc sulphate), (4) pollarding trees at 4 m height with application of N, P, K and trace elements, (5) drenching with the
flowering promoter Paclobutrazol (0.25 ml active ingredient per cm of stem girth) along with N, P, K and trace elements. At
Panampalli, a higher-rainfall site in Kerala State, only treatments 1, 2 and 3 were applied. Four replicates of treatment
plots sized 18 m × 18 m, with 22–32 trees per plot were set up in each orchard in randomized complete block designs. Untreated
plots of E. camaldulensis and E. tereticornis at Pudukkottai displayed 12 and 21% fertile trees, respectively, in the first year of monitoring, while at Panampally the
percentage of fertile trees in untreated E. camaldulensis plots was higher at 72%, and that of E. tereticornis similar at 23%. Both species attained greater stem diameter at breast height at age 9 years at the higher-rainfall location
but there was no significant impact of fertilizer application on 9-year diameter at either site. Diameter was reduced by pollarding
and Paclobutrazol application at Pudukkottai. Only Paclobutrazol produced a significant increase in fertility in both species
for four successive years, increasing the percentage of fertile trees to 59 and 71%, respectively, for E. camaldulensis and E. tereticornis 1 year after application. The number of capsules produced per tree also increased significantly with Paclobutrazol application,
although the difference was comparatively less by the fourth year. The number of capsules per umbel did not differ significantly
between locations, whereas the germination rate varied between treatments although no consistent trends were observed. 相似文献
9.
Coppicing is an alternative reforestation tool for teak in the tropics, substantially reducing regeneration time/costs and associated demands for labor and seed when available. Growth rates of coppiced material are rapid in most situations, but stem/wood quality is a frequent concern. We compared coppiced teak plantations to paired seed-origin plantations, at ages 3, 8, and 13 years, on Forest State Corporation managed land located in Java, Indonesia. Teak trees were evaluated for height, diameter, lower-bole straightness, and presence of disease in both plantation types and at three ages. Mean height and diameter of trees in coppiced plantations were both significantly greater than that in their paired seed-origin plantations at all three ages. Furthermore, heights and diameters in coppiced plantations were higher than expected based on established growth tables for Java. Coppiced plantations were less symptomatic of disease than seed-origin plantations, which promises better wood production and quality. Lower-bole stems in coppiced plantations developed less straight than those in seed-origin plantations, but these deviations faded with time and will likely become insignificant within a 60-year rotation. Based on these results from existing coppiced plantations in Java, coppiced plantations can make a major contribution to teak production in Indonesia. 相似文献
10.
[目的]通过对思茅松自由授粉子代测试林的生长与形质性状遗传参数的估计,进行优良家系选择,为建立思茅松高世代种子园及培育优良无性系苗木提供种质资源。[方法]采用随机区组试验设计,在214个思茅松自由授粉家系子代测试林中选择胸径、地径、树高、枝下高、冠幅、通直度、树干圆满度、树冠圆满度、材积及地上生物量等生长与形质性状,利用线性混合模型进行遗传参数的估计,进行优良家系筛选。[结果]思茅松自由授粉子代测试林生长与形质性状的遗传参数在家系间差异极显著。各性状的家系遗传力较高,其中,地径的家系遗传力最大(1.105)。材积的预期遗传增益高于地上生物量,利用家系/家系内选择方法进行优良家系的筛选,材积的预期遗传增益为60.75%,入选家系为60个;地上生物量的预期遗传增益为44.22%,入选家系为66个。轮盘数、通直度和树干圆满度对材积和地上生物量都有显著影响。[结论]在早期选择中,形质性状的遗传变异对思茅松自由授粉优良家系的选择有重要参考作用,4年生思茅松自由授粉家系子代测试林中各性状存在着丰富的遗传变异,在早期选择中可以筛选出适合不同培育目标的优良家系,最大限度挖掘其遗传潜力。 相似文献
11.
【目的】研究与评价马尾松一代、二代无性系种子园的遗传增益及改良效果,指导马尾松良种选育、生产及应用。【方法】利用营建在浙江省淳安县燕山林场和福建省邵武市卫闽林场的6年生马尾松一代和二代自由授粉家系遗传测定林,分析不同世代种子园子代生长性状的遗传变异,并进行家系育种值估算及生长评价。【结果】马尾松不同世代的种子园子代生长差异很大,其树高、胸径和单株材积等生长量显著大于马尾松优良天然林分的混系子代,其中一代种子园子代各家系单株材积表型值和育种值分别大于优良天然林分混系55.78%~84.62%和40.66%~71.39%,二代其值分别大于优良天然林分混系58.96%~108.97%和42.97%~91.89%,二代种子园子代的平均生长量和遗传稳定性总体上高于一代种子园子代。树高、胸径和单株材积等主要生长性状在世代内家系间的生长差异均达极显著水平,在一代种子园子代中最优家系的树高、胸径和单株材积分别大于最差家系21.94%、30.72%和97.75%,在二代种子园子代中最优家系的树高、胸径和单株材积分别大于最差家系23.42%、29.60%和90.09%,说明种子园中对亲本材料的再选择非常重要。依据子代的单株材积育种值在两测定点的位次及其变幅大小,将38个家系分成速生型、较速生稳定型、较速生不稳定型和慢生型4类,各类所占家系数分别有23.68%、26.32%、21.05%和28.95%,其中速生型和较速生稳定型家系所对应的亲本无性系可作为新建马尾松二代无性系种子园的优良建园材料。种子园子代主要生长性状的地点×家系、区组×家系的互作效应极显著,说明各家系在不同立地环境中生长表现不一致。【结论】马尾松无性系种子园良种效益显著,二代增益大于一代。通过选择速生型和较速生稳定型家系将有助于种子园建园亲本的再选择、现有种子园的留优去劣疏伐和重建新的种子园。鉴于子代主要生长性状的基因型与环境互作使各家系在不同立地环境中生长表现不同,建议对子代生长表现突出、结实量较多的无性系进行单系采种利用。 相似文献
12.
Aleš Kadunc 《European Journal of Forest Research》2007,126(3):349-358
Sycamore (Acer pseudoplatanus L.) is a tree species with highly valuable wood. Similar to European beech (Fagus sylvatica L.), the stemwood of sycamore can be devalued due to the discolouration i.e. brown heart (hearwood discolouration, hereafter).
This paper aims to establish the influence of tree traits and site characteristics on the formation of heartwood discolouration
and the possibility of predicting the occurrence of heartwood discolouration. For this purpose, 351 sycamore trees from 38
sites in Slovenia, most of them on carbonate bedrock and in the mountain vegetation belt, were analysed. Stem analysis was
carried out on all the trees and the age, diameter at breast height (dbh), height of crown base, forking and crown size, were
established. On the stump and upper fronts of the first and second logs, the maximum heartwood discolouration diameter was
measured. Using logistic regression, the positive influence of age, relative crown length and average diameter increment on
the formation of heartwood discolouration was ascertained. Conversely, the probability of heartwood discolouration was diminished
by diameter increment in the last 20 years. In the less productive sites, the probability of formation of heartwood discolouration
was relatively high in small diameter trees, but it increased slowly with diameter. Tree forking also contributed to a large
extent of the heartwood discolouration. After the diameter at breast height achieves 45 cm, the formation of heartwood discolouration
on the first log is highly probable. As in beech, the heartwood discolouration increases along the stem axis up to a height
of 6–8 m, and decreases in the higher parts of the tree. 相似文献
13.
We tested the effects of exponential nutrient loading and springtime carbon loading during nursery culture on the field performance
of black spruce (Picea mariana (Mill.) B.S.P.). Seedlings were grown from seed with a conventional, fixed dose fertilizer (10 mg N seedling−1) or an exponential nutrient loading regime (75 mg N seedling−1). The following spring, seedlings were exposed for two weeks to either ambient (370 ppm) or elevated levels of CO2 (800 ppm) and then planted in the field; seedling growth was followed for the next six years. Exponential nutrient loading
increased seedling height, stem diameter and leader growth, with the largest increases in height and leader length occurring
in the first three years after outplanting. Carbon loading increased seedling height and leader length, but only in seedlings
that had been exponentially nutrient loaded. A combination of carbon and nutrient loading increased shoot height 26%, stem
diameter 37% and leader length 40% over trees that received neither treatment. These results demonstrate that the growth enhancement
seen under exponential nutrient loading is maintained under field conditions for at least six years. Carbon loading just before
outplanting was a useful supplement to nutrient loading, but was ineffective in the absence of nutrient loading. 相似文献
14.
Chemulanga Josiah Chiveu Otto George Dangasuk Michael Eliazar Omunyin Francis Nyamu Wachira 《New Forests》2009,38(1):1-14
Acacia senegal (L.) Willd. is an African leguminous multipurpose tree species belonging to subfamily Mimosoideae and subgenus Aculeiferum, highly valued for gum arabic production. This study estimated the genetic diversity within and among Kenyan populations
of the species in the Bulla Sambul, Kutulo, Wamba and Meisori populations based on 12 quantitative traits, which included;
tree height, diameter at breast height (DBH), number of branches, bark thickness, gum weight and various pod and seed traits
on 20 randomly selected trees in every population. Duncan’s multiple range test (DMRT) and the dendrogram distinctively divided
the populations into two groups; Wamba and Meisori in one group while Bulla Sambul and Kutulo in the other, indicating geographical
structuring of the genetic variability. The trees were larger, taller with greater pod and seed traits in the Wamba and Meisori
than the Bulla Sambul and Kutulo populations. Contrarily, trees had lighter seeds, more branches with higher gum weight in
the Kutulo and Bulla Sambul than the Wamba and Meisori populations. The Shannon–Weaver diversity index (H), depicted 1,000-seed weight as the most varied trait across the populations. These findings provide essential information
on the genetic diversity of the species, necessary for delineation of particular zones for seed sources for germplasm conservation,
selection for domestication and improved gum arabic production. 相似文献
15.
Susumu Kurinobu Daryono Prehatin Naiem Mohanmad Kenji Matsune 《Journal of Forest Research》2007,12(6):473-478
A stem taper equation compatible to the volume equation was derived from the data of 172 trees sampled in the three plantations
of Paraserianthes falcataria in Pare, East Java. The stem taper equation in this study was based on a conventional logarithmic volume equation, with the
addition of one free parameter that minimized the standard errors of estimate to the observed diameter of stems at 1.0-m intervals.
The derived equation was able to predict the stem taper of P. falcataria reasonably well, while it was not flexible enough to describe delicate changes of the taper in the upper portion of stem.
The equation was able to predict bole length and the volume up to the top diameter 20 cm, the diameter size merchantable for
sawn timber in Indonesia, with reasonable accuracy. An appropriate rotation age for sawn-timber production was found to be
8–9 years old, at which the mean annual increment of sawn timber would be maximized. 相似文献
16.
Takuya Kajimoto Gaku Hitsuma Takashi Masaki Tatsuo Kanazashi 《Journal of Forest Research》2006,11(2):107-116
We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since
the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and
the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were
used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the
ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates
during the early stage (i.e., 60–70 years after planting); however, after this period, only the height growth rates declined
sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40–60 years. Subsequently,
the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually
decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree
competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including
the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sapwood
area at a height of 4 m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about
12.8 m3 ha−1 year−1. This estimate was higher than those of some old natural T. dolabrata forests (2.0–8.6 m3 ha−1 year−1) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study
plantation (0.03 m3 tree−1 year−1) was within the range of these natural stands (0.01–0.05 m3 tree−1 year−1). These comparisons suggested that the old T. dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of
tree density in the past. In terms of timber production, this fact implied that a rather long rotation (>100 years) can be
applicable in the management of T. dolabrata plantations. 相似文献
17.
Growth of regenerating trees in different light environments was studied for the mountainous, mixed-species forests in the Carpathian Mountains of Romania. The primary species in these mixtures were silver fir (Abies alba Mill.), European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst). Seedlings/saplings of these species were selected and measured in different stands from two different geographical locations. Regenerating trees were measured for height and diameter growth during the summer of 2002. For each seedling/sapling, percentage of above canopy light (PACL) and stand basal area (BA) were used to assess available and occupied growing space respectively. Regeneration growth was compared against these two variables and regression relationships were developed. Using these models, we predicted the dynamics of regeneration as both growth and species composition. Our results showed that in low-light environments (PACL<20–35%; BA>30 m2/ha), shade tolerant fir and beech clearly outcompeted the spruce. Therefore, in dense stands, spruce could be eliminated by the shade tolerant species. For intermediate levels of cover (PACL=35–70%; BA=15–35 m2/ha) the spruce grew at comparable rates as the beech and fir. All three species showed similar growth rates in open conditions (PACL>80–90%; BA<15–20 m2/ha) with the spruce having a tendency to outgrow the others. However, in terms of establishment, such conditions favor spruce and inhibit fir and beech. 相似文献
18.
Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural populations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old progenies were investigated. Results show that the average intra-family coefficient of variation (CV) in height growth of the 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV (14.02%). Correspondingly, these two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were significantly differed in their general combining abilities (GCA) and relative effect values of GCA (RGCA) of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high family heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in height growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboides for seed collection. 相似文献
19.
Plant growth, biomass production and nutrient accumulation by slash/mulch agroforestry systems in tropical hillsides of Colombia 总被引：1，自引：0，他引：1
Planted fallow systems under ‘slash and mulch’ management were compared with natural fallow systems at two farms (BM1 and
BM2) in the Colombian Andes. The BM1 site was relatively more fertile than the BM2 site. Planted fallow systems evaluated
included Calliandra calothyrsus CIAT 20400 (CAL), Indigofera constricta (IND) or Tithonia diversifola (TTH). During each pruning event slashed biomass was weighed, surface-applied to the soil on the same plot and sub-samples
taken for chemical analyses. While Indigofera trees consistently showed significantly greater (p < 0.05) plant height and collar diameter than Calliandra trees at both study sites, only collar diameter in Indigofera was significantly affected at all sampling times by differences between BM1 and BM2. After 27 months, TTH presented the greatest
cumulative dry weight biomass (37 t ha–1) and nutrient accumulation in biomass (417.5 kg N ha–1, 85.3 kg P ha–1, 928 kg K ha–1, 299 kg Ca ha–1 and 127.6 kg Mg ha–1) among planted fallow systems studied at BM1. Leaf biomass was significantly greater (P < 0.05) for CAL than IND irrespective
of site. However, CAL and IND biomass from other plant parts studied and nutrient accumulation were generally similar at BM1
and BM2. At both sites, NAT consistently presented the lowest biomass production and nutrient accumulation among fallow systems.
Planted fallows using Calliandra and Indigofera trees had the additional benefit of producing considerable quantities of firewood for household use.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
Possibility of improvement in fundamental properties of wood of acacia hybrids by artificial hybridization 总被引：1，自引：0，他引：1
Nguyen Tu Kim Junji Matsumura Kazuyuki Oda Nguyen Viet Cuong 《Journal of Wood Science》2009,55(1):8-12
Growth, specific gravity, and wood fiber length of Acacia mangium, Acacia auriculiformis, artificial acacia hybrid clones, and combinations, which were planted in a trial forest in Bavi, Vietnam, in July 2001,
were examined. The radial variations from pith to bark were investigated to clarify the effect of genetic factors on these
traits. Superiority of hybrids over their parents ranged from 36.3% to 41.6% for diameter, from 20.0% to 25.3% for height,
from 6.9% to 20.7% for specific gravity, and from 6.1% to 12.8% for wood fiber length. The hybrid possessed heterosis in diameter,
height, specific gravity, and wood fiber length regardless of whether the female parent was A. mangium or A. auriculiformis. The profiles of wood fiber length and specific gravity in the radial direction were similar for all the trees investigated.
Wood fiber length was initially 0.5–0.6 mm near the pith and then increased slowly, finally reaching 1.0–1.2 mm near the bark.
The specific gravity of acacia increased from 0.49–0.58 near the pith to 0.63–0.74 near the bark. From a relative distance
of 30% from the pith, the specific gravity increased slightly and seemed to be stable. The relations among tree diameter,
specific gravity, and wood fiber length were fair and could be represented by positive linear regression formulas. Hybrids
for which A. auriculiformis was the female parent and A. mangium was the male parent had a faster growth rate and longer wood fibers than the inverse hybrids.
Part of this report was presented at the 6th Pacific Regional Wood Anatomy Conference, Kyoto, Japan, December 2005 相似文献