Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties; II. Fibre length and coarseness

Within-tree variation in fibre length and coarseness was studied in fifty trees of E. globulus and E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m) and at eight percentage heights (0, 10, 20, ... 70%). Whole-tree values, calculated from percentage height data, were correlated with the core data to determine the optimal sampling height. Core samples were found to be reliable predictors of whole-tree fibre length, but results were variable for fibre coarseness. Simulated cores taken from the recommended sampling heights explained 87% and 71% of variation in whole-tree fibre length for E. globulus and E. nitens respectively and 54% and 45% of the variation in whole-tree fibre coarseness. Fibre length at all fixed heights showed good correlations with whole-tree values at all sites for E. globulus. For E. nitens the correlations were slightly lower and variable across sites. Results for fibre coarseness varied across sampling heights and sites for both species. The recommended sampling height for fibre length is 1.5 m for both species, whilst for fibre coarseness, the recommended sampling heights are 0.9 and 1.1 m for E. globulus, and 0.9 and 1.3 m for E. nitens. Radial orientation of cores was not important and neither fibre length nor coarseness were related to tree size or basic density. To estimate stand mean fibre length to an accuracy of ±5% would require sampling 9 whole trees or taking cores from 13 trees for E. globulus and 4 whole trees or cores from 8 trees for E. nitens. For estimating stand mean fibre coarseness, 10 whole trees of E. globulus and 7 whole trees are needed for E. nitens. Core sampling for stand mean coarseness would require more trees: 13 to 21 for E. globulus and 11 to 16 trees for E. nitens. Received 17 September 1998     

Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. III. Predicted pulp yield using Near Infrared Reflectance Analysis

  Within-tree variation in kraft pulp yield, predicted using near infrared reflectance analysis, was studied in thirty trees of E. globulus and fifty trees of E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m) and at seven percentage heights (0, 20, 30, ... 70%). Whole-tree values, calculated from percentage height data, were correlated with the core data to determine the optimal sampling height. Core samples were found to be good predictors of whole-tree pulp yield for E. globulus, with simulated cores taken from the recommended sampling height (1.1 m) explaining more than 50% of variation in whole-tree pulp yield. Results for E. nitens were variable with large site differences apparent. On high quality sites, core samples from the recommended sampling height (0.9 m) were good predictors of whole-tree pulp yield, explaining around 60% of the variation. On poor quality sites, cores were poor predictors of whole-tree pulp yield. Radial orientation of cores was not important and predicted pulp yield was not related to tree size, basic density or fibre length. To estimate stand mean pulp yield to an accuracy of ±1% would require sampling 6 trees of E. globulus and 4 trees for E. nitens using either multiple discs or core samples. A single sampling height (1.1 m) is recommended for sampling for basic density, fibre length, fibre coarseness and predicted pulp yield in E. globulus. For E. nitens the recommended sampling height for basic density and fibre length is 0.7 m and 0.9 m is recommended for predicted pulp yield on good quality sites. Received 17 September 1998     

How dense is my blue gum? prediction of whole-tree basic density of <Emphasis Type="Italic">Eucalyptus globulus</Emphasis>

Accurate prediction of whole-tree wood basic density (BD) from indirect density measures is important for estimating Eucalytpus globulus breeding values and genetic gain. We measured 100 E. globulus trees at 6.5 years of age on each of a high productivity site (Albany) and a low productivity site (Esperance), sampling 16 full-sib families and seven open-pollinated ‘check’ seedlots. On each tree we assessed pilodyn penetration at 1.3 m and BD of: (a) the outer 10 mm which was penetrated by the pilodyn pin of a bark-bark core, (b) a whole bark-bark core at 1.3 m, (c) a cross-sectional disk at 1.3 m and (d) the whole tree, represented by cross-sectional disks at five heights. Site effects and genetic values for families and checks were determined by mixed model analysis. A trend of increasing BD from pith to bark was more pronounced at Albany, where wood formed before age 3.5 years was 12 kg/m³ less dense than at Esperance (P = 0.01) and wood formed from 3.5 to 6.5 years was 27 kg/m³ denser than at Esperance (P < 0.001). Mean whole-tree BD was 19 kg/m³ greater at Albany (P < 0.001). Pilodyn penetration was well-correlated with BD of the 10 mm sample of penetrated wood and this relationship was not greatly affected by site variation. Genetic values for pilodyn penetration formed precise relationships with BD of breast-height discs and whole-tree BD although they were site-specific. Pilodyn penetration was a better predictor for genetic values of whole-tree BD than were bark-bark cores.     

Positioning precision and sampling number of DGPS under forest canopies

 Experimental results were studied to determine the relationships between positioning precision of a differential global positioning system (DGPS) and forest type, antenna height, and season, and to clarify the relationship between sampling number and the convergence of positioning precision. Observation was carried out for 24 h. Mean circular area probability (CEP₉₅) was 2.80 m for deciduous broadleaved trees, and 4.99 m for conifers. The mean CEP₉₅ taken at 7 m height (3.14 m) was higher than that at 1 m height (3.92 m) at all sites. The mean CEP₉₅ taken during the defoliation season (2.65 m) was slightly better than during the foliation season (2.96 m). There were significant differences between forest types (P < 0.001) and antenna heights (P < 0.05). Positioning precision was not noticeably improved if the sampling number was around ten or less. A sampling number of 100–1000 or more is required before substantial improvements can be expected. As long as high positioning precision is not required, it is acceptable to use 2D & 3D modes and relatively few samples to take measurements. Received: April 24, 2002 / Accepted: October 10, 2002 Correspondence to:I. Sawaguchi     

Examination of within-tree variations and the heights representing whole-tree values of derived wood properties for quasi-non-destructive breeding of Eucalyptus camaldulensis and Eucalyptus globulus as quality pulpwood

Within-tree variations of derived wood properties of Runkel ratio, Luces shape factor, slenderness ratio, and solids factor were examined for Eucalyptus camaldulensis and Eucalyptus globulus trees and the tendency difference in the within-tree variations between individuals and between species, in both radial and axial directions by statistical data analysis. These properties are important for quality breeding of pulpwood. In both species, within-tree variations were generally observed as higher values in the upper and outer parts compared with other parts of the trunk for Runkel ratio and Luces shape factor. In E. camaldulensis, within-tree variations were observed as higher values in the upper and outer parts compared with other parts of the trunk for slenderness ratio and solids factor. In E. globulus, within-tree variations were observed as higher values in the outer parts compared with other parts for slenderness ratio and solids factor. However, significant difference of tendency was observed in radial variation between individuals of E. globulus for Runkel ratio and in both radial and axial variations between species for solids factor. Furthermore, within-tree variations of derived wood properties were analyzed to determine a sampling height in the trunk which can be used to represent whole-tree values. Representative heights of derived wood properties from two trees were found to be 2.8m in E. camaldulensis (except for Runkel ratio and Luces shape factor) and 1.8m in E. globules (except for Runkel ratio), regardless of differences in tree height (growth rate) and in tendency of within-tree variation of derived wood properties.     

Impact of Botryosphaeria,Diplodia and Neofusicoccum species on two Eucalyptus species and a hybrid: From pathogenicity to physiological performance

Species of Botryosphaeriaceae are associated with canker and dieback of Eucalyptus spp. worldwide, but little is known about their effect on the host physiology. The aim of this study was to evaluate the impact of Botryosphaeriaceae isolates from nine species in three genera (Botryosphaeria, Diplodia and Neofusicoccum), previously isolated from eucalypts, on three different Eucalyptus hosts (seedlings of E. nitens, cuttings of E. globulusand of E. globulus× E. cypellocarpa). An approach combining standard pathogenicity trials with evaluation of plant morpho‐physiological parameters was used. The size of the lesions produced revealed differences in fungal aggressiveness and host susceptibility. Isolates of Neofusicoccum kwambonambienseand Diplodia corticolawere the most aggressive, while Botryosphaeria dothidea and Diplodia seriataisolates were the least aggressive. In general, hybrid E. globulus× E. cypellocarpa plants developed smaller lesions, followed by E. nitens and E. globulus. Eucalyptus nitensplants showed minimal modifications on the morpho‐physiological profile when infected, although more severe symptoms and mortality were observed. This is probably due to a more variable genetic background of the plants. However, in general, no direct association between putative fungal aggressiveness and plant physiological disorders could be found. Results suggested that under optimal growth conditions plants manage to cope with pathogen attack and maintain their physiological performance.     

Where to shoot your pilodyn: within tree variation in basic density in plantation Eucalyptus globulus and E. nitens in Tasmania

Longitudinal patterns of within tree variation for basic density were determined for plantation Eucalyptus globulus (ages 5 and 10 years) and E. nitens (ages 5, 10 and 15 years) growing in three geographic areas in Tasmania. Each tree was sampled by taking discs from a combination of percentage heights (0, 10, 20 ___ 70%) and fixed height samples (0.5 m, 0.7 m ___ 1.5 m). At each of the fixed heights, a single pilodyn reading was taken from each of 4 aspects. Weighted whole tree density was calculated from the percentage height samples and used for correlation and regression analysis with the fixed height samples. Both species showed an initial drop in density between the felling cut (zero height) and 0.5 m, followed by a linear increase in density between 10% and 70% of tree height. Slope of fitted regressions were parallel within species but differed significantly between the species (1.14 kg/m³ and 1.62 kg/m³ per 1% increase in height above 10% for E. globulus and E. nitens, respectively). Density at all fixed heights was highly correlated with whole tree values for E. globulus, but results were variable across sites for E. nitens. Both species were found to contain trees which produced aberrant pilodyn readings. For E. globulus, the optimal sampling height was 1.3 m above ground and the mean pilodyn reading was found to predict whole tree density with an accuracy of ±21 kg/m³. For E. nitens, optimal sampling height was 1.5 m above ground. However, pilodyn readings around the stem were not very repeatable and correlations with whole tree density were lower, resulting in the accuracy of prediction of whole tree density being ±26 kg/m³.     

Representative heights for assessing whole-tree values of cell-type proportions in Eucalyptus camaldulensis and E. globulus

Eucalyptus camaldulensis Dehnh. and E. globulus Labill. are economically important species for wood and pulpwood materials. Representative heights for assessing whole-tree values of cell-type proportions(vessels, fibers, ray and axial parenchyma percentages) using increment cores were examined by analysis of within-tree variations. Pattern differences were evaluated between trees and species in both radial and axial directions by statistical data analysis(Moses test). In E. camaldulensis,within-tree variation of vessel percentage was generally higher in the upper and outer regions of the trunk. In contrast, E. globulus within-tree variation was unclear. In both species, although no clear pattern of fiber percentages was observed, within-tree variations of ray and axial parenchyma levels were higher in the lower and inner regions.Significant differences in patterns were observed in the axial variation between species for vessel percentages and in the radial variation between trees of E. camaldulensis for ray parenchyma percentages. The representative heights for assessing whole-tree cell-type proportions were 0.8 mabove the ground for E. camaldulensis and 2.8 m for E.globulus, regardless of differences in tree height and pattern of within-tree variation of cell-type proportions.     

An evaluation of the conical approximation as a generic model for estimating stem volume, biomass and nutrient content in young Eucalyptus plantations

Accurately and non-destructively quantifying the volume, mass or nutrient content of tree components is fundamental for assessing the impact of site, treatment, and climate on biomass, carbon sequestration, and nutrient uptake of a growing plantation. Typically, this has involved the application of allometric equations utilising diameter and height, but for accurate results, these equations are often specific to species, site, and silvicultural treatment. In this study, we assessed the value of incorporating a third piece of information: the height of diameter measurement. We derived a more general volume equation, based on the conical approximation, using a diameter projected to the base of the tree. Common equations were developed which allowed an accurate estimate of stem volume, dry weight and nutrient content across two key plantation grown eucalypt species, Eucalyptus grandis W. Hill ex Maiden and Eucalyptus globulus (Labill.). The conical model was developed with plantation-grown E. grandis trees ranging from 0.28 to 15.85 m in height (1.05 g to 80.3 kg stem wood dry weight), and E. globulus trees ranging from 0.10 to 34.4 m in height (stem wood dry weight from 0.48 g to 652 kg), grown under a range of contrasting cultural treatments, including spacing (E. grandis), site (E. globulus) and fertilization (nitrogen and phosphorus) for both species. With log transformed data the conical function (V_con) was closely related to stem sectional volume over bark and stem weight (R² = 0.996 and 0.990, respectively) for both E. grandis and E. globulus, and the same regressions can be applied to both species. Back transformed data compared with the original data yielded modelling efficiencies of 0.99 and 0.97, respectively. Relationships between V_con and bark dry weight differed for the two species, reflecting differing bark characteristics. Young trees with juvenile foliage had a different form of relationship to older trees with intermediate or adult foliage, the change of slope corresponding to heights about 1.5 m for E. grandis and age 1 year for E. globulus. The V_con model proved to be robust, and unlike conventional models, does not need additional parameters for estimating biomass under different cultural treatments. More than 99% of the statistical variance of the logarithm of biomass was accounted for in the model. V_con captures most of the change in stem taper associated with cultural treatments and some of the change in stem form that occurs after the crown base has lifted appreciably. Fertilization increased N and P concentrations in stem wood and bark, and regressions to estimate N and P contents (the products of biomass and concentration) were dependent on treatment. For instance, there was a large growth response to N fertilization in E. globulus corresponding with a change (P < 0.05) in the intercept of the regression to estimate N content.     

以芳香油和薪材为最终产品的桉树幼林地上部分生物量研究*

在2年生的桉树引种试验林内,对蓝桉和新引种的5种其他桉树的地上部分生物量进行了测定。研究发现,当轮伐期为2年时,不同桉树的芳香油和薪材收获量差异显著,而同一树种的芳香油和薪材产量在不同造林密度之间无显著差异。史密斯桉和贝克桉的芳香油和桉树脑含量均高于蓝桉,是生产桉树芳香油和薪材的优良树种,在我国亚热带地区有进一步试验和推广的价值。     

Batch measurements of wood density on intact or prepared drill cores using x-ray microdensitometry

The performance of a batch scanning x-ray densitometer for measuring wood density without sample preparation, i.e., on intact drill cores, or on rectangular samples prepared from drill cores, was analysed. Effects of x-ray intensity, sample thickness and fiber direction, as well as extractives content, were evaluated for young (mainly sapwood) and old (mainly heartwood) wood from Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). The x-ray power level used as standard (1.4 kW; 40 kV and 35 mA) seemed appropriate for the tested species and specimen thickness. The density of intact drill cores could be determined with a mean standard deviation of 1.6% for each sample, with a single machine run, if the cores were mounted with a fixed fiber direction and calibrations were made for each wood type. The corresponding precision for rectangular samples was 1.0%. Further improvements are attainable by using standard reference samples in each machine run and batch-wise analysis. For the chosen wood types and measurement technique, a sample thickness of 5 mm should give the best precision. However, for species with very narrow rings, thinner samples would improve the spatial resolution when ring boundaries are angled or curved. Extractives should be removed, especially for pine, but possibly also for spruce, if high precision in density determination is required. Received 19 January 2000     

Comparison of <Emphasis Type="Italic">Pinus taeda</Emphasis> L. whole-tree wood property calibrations using diffuse reflectance near infrared spectra obtained using a variety of sampling options

A necessary objective for tree-breeding programs, with a focus on wood quality, is the measurement of wood properties on a whole-tree basis, however, the time and cost involved limits the numbers of trees sampled. Near infrared (NIR) spectroscopy provides an alternative and recently, it has been demonstrated that calibrations based on milled increment cores and whole-tree data can provide good estimates of whole-tree properties. Several options exist for sampling standing trees and the aim of this study was to compare wood property calibrations based on NIR spectra collected from samples obtained using different sampling methods. Calibrations for whole-tree lignin and basic specific gravity based on NIR spectra from whole-tree chips (milled or intact) had the strongest statistics, calibrations based on NIR spectra from milled increment cores were similar. Other options for sampling the tree (drill shavings, etc.) gave errors that were too large for practical applications. If an increment core is going to be used to estimate whole-tree properties, it is recommended that it be dried and milled prior to analysis.     

Shrinkage-related degrade and its association with some physical properties in Eucalyptus regnans F. Muell

Summary Assessments of internal checking and the physical properties of 124 trees of Eucalyptus regnans F. Muell. have shown that for material dried under relatively mild predryer conditions (30 °C, 65% RH) internal checking was highly positively correlated with each of collapse, moisture content and normal shrinkage, and weakly negatively correlated with total external shrinkage. Collapse alone explained 47% of the variation in internal checking. Incidence of internal checking in sample boards could be estimated with moderate success by each of the following properties measured on board ends: collapse, the number of internal checks and initial moisture content. Material with high mean basic density above 530 kg/m³ was associated with low levels of internal checking and collapse. However, the maximum naturally occurring density of E. regnans was not high enough to obviate collapse and internal checking. It was observed that growth rings in 100 × 50 mm backsawn boards in which the earlywood air-dry density was below 450 kg/m³ showed internal checking. The size and number of internal checks increased with a decrease in earlywood density. It was shown that drying E. regnans below temperatures of 24–30 °C does not eliminate collapse, thus raising doubt about the validity of a temperature threshold concept in that range. Received 17 September 1997     

Insect (Salebria sp.) infestation and impact on Vitellaria paradoxa C.F. Gaertn. fruit production in agroforestry parklands

Vitellaria paradoxa, known as Shea tree or karité, is one of the dominant trees of agroforestry parklands in Sahelian region with an immense commercial value. In this study, we examined infestation of fruit-bearing shoots and fruits on two sites in western Burkina Faso across different reproductive phenophases, crown heights and aspects. The number of infested and healthy shoots and fruits were counted on 60 reproductively active trees randomly selected from on-year shea trees in each site, using a metal frame (0.5 × 0.5 m) to mark a fixed area of the canopy for sampling. The shoot and fruit borer was identified as Salebria sp. (Lepidoptera:Pyralidae), which was not reported earlier. The proportion of infested trees and shoots varied significantly between sites and among reproductive phenophases (P < 0.0001). The site close to the natural forest had the highest infestation rate than distantly located site. Among reproductive phenophases, the proportions of infested trees and shoots were the highest during flowering and fruit set, respectively. Fruit infestation also varied significantly between sites, crown heights and aspects (P < 0.001). The site close to the natural forest and the crown with north-east aspect were heavily infested while the bottom part of the crown had the lowest infestation. As a whole, 49–80% of trees, 24–31% of shoots and 4–15% of fruits were found infested, depending on the site. These infestation levels combined with precocious flower and fruit abscissions would pose serious economic losses that justify a call for immediate pest control initiatives.     

Combining empirical models and the process-based model 3-PG to predict Eucalyptus nitens plantations growth in Spain

Empirical, statistically based models were used to describe the growth and development of Eucalyptus nitens plantations for a range of site productivities and the standard biomass and pulp silvicultural regime currently applied in Northern Spain. The results obtained, along with data gathered from a network of 68 plots, 48 trees felled for biomass estimations and 73 trees sampled for foliar area estimation were used to parameterize the 3-PG model for this species in Northern Spain. Most parameters associated with allometric relationships and partitioning (i.e. bark and branch fraction, basic density, age modifier and mortality) were derived from local data, and the remaining parameters were obtained from published studies on E. nitens or default values previously used for E. globulus. The parameterized model was validated with data from three trials measured from age 3 years until age 8-14 years, and performed better than the empirical model in terms of total stand under bark volume, mean diameter at breast height, basal area and foliar biomass. The process-based model was then used to forecast changes in plantations subjected to a clearwood regime, initializing the model at age 3 years, considering 3 prunings, 2 thinnings and lengthening the rotation to 18 years. This integrated regime was able to provide biomass for bioenergy, pulp or fibreboard wood and also solid wood, with thinning operations assisting the financial viability, and was a potentially good alternative for productive sites.     

Growth pattern analysis and stemwood production in an unmanaged old plantation of hiba, Thujopsis dolabrata, in northern Japan

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.     

Defence responses in plantation‐grown Eucalyptus globulus and Eucalyptus nitens after artificial fungal inoculation

The formation of reaction and barrier zones was studied in the xylem of Eucalyptus globulus and Eucalyptus nitens tree stems after wounding and artificial inoculation with two white rot fungi. The study had two objectives: to describe host responses in Eucalyptus spp. by light microscopy and to determine whether they would differ in a fungal treatment (wounding and inoculation by one of two fungal isolates) when compared to a control treatment (wounding only). Eucalyptus globulus and E. nitens developed similar reaction and barrier zones. The E. globulus barrier zone was characterized by kino vein formation. In both hosts, the reaction zone was primarily influenced by content and distribution of living tracheids and parenchyma cells within the sapwood. By contrast, the anatomy of the barrier zone showed similarities to the basic xylem structure of each host, except for some cell types that were newly formed (sclereids, kino veins) or increased in number (parenchyma cells, tracheids). Other cell types were reduced in number or completely absent. Host response in terms of barrier zone width appeared to be greater in the fungal than control treatment. Both wood decay fungi appeared to induce a wider barrier zone in both species than that associated with non‐specific damage caused exclusively by wounding. However, the small number of replicates available for this study was possibly insufficient to provide statistical evidence for different barrier zone width between fungal and control treatments.     

Sampling procedure for density estimation of bamboo galls induced by <Emphasis Type="Italic">Aiolomorphus rhopaloides</Emphasis> (Hymenoptera: Eurytomidae) in a bamboo stand

 To establish a sampling procedure for estimating the density of bamboo galls induced by Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae) in a stand of bamboo Phyllostachys heterocycla (Carr. Mitf.) (Monocotyledoneae: Gramineae), 5–12 bamboo culms were cut at random in late March of each year during 1998–2001 just before gall-maker emergence. The number of galls on the branches of each bamboo culm was counted. The spatial patterns of the galls on the culms in the stand and on the branches within each culm were measured by Iwao's patchiness regression. Galls were distributed contagiously both on culms and on branches. Current bamboo culms that emerged the previous summer did not require sampling because no galls were observed on them. Except for this, there was no difference in gall density on young and old culms, suggesting that it is not necessary to distinguish them. There were few (<4%) galls above 6 m height during the 4 years. There was no significant difference in gall density up to 4 m and above 4 m, suggesting that branches up to 4 m can be sampled with confidence. Kuno's two-stage sampling method at different precision levels showed that the number of culms to be sampled varied with gall density. For example, at mean density m = 1.0 per branch when the number of sampled branches per culm is 10, a total of 24 culms is required to estimate gall number at a precision level of D = 0.2, where D is the ratio of standard error to mean. Received: July 10, 2002 / Accepted: November 25, 2002 Acknowledgments I thank Dr. K. Kamijo for insect identification. Thanks are also due to the members of the Laboratory of Forest Protection for their kind help with the fieldwork. This study was supported in part by a Grant-in-Aid for Scientific Research (No. 11460068) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.     

Effects of resource plant size on rooting of <Emphasis Type="Italic">Dryobalanops lanceolata</Emphasis> cuttings

 Cuttings from older trees of the Dipterocarpaceae generally lose their ability to root. However, branches in a canopy of adult dipterocarps are a possible source of cuttings because they show juvenile characteristics in architecture due to “adaptive reiteration”, suggesting physiological rejuvenation. Effects of resource plant size on the rooting of cuttings and the possibility of using cuttings from reiterated branches of adult trees were studied for Dryobalanops lanceolata, an emergent dipterocarp species. A cutting experiment with non-mist propagators was conducted for cuttings collected from resource plants of four different size classes: <2 m, 2–5 m, 8–15 m, and 70 m in height. The smallest size class included two different age classes: <2 and >2 years old. Cuttings from the tallest resource plant were collected from reiterated branches. Rooting percentage was negatively correlated with resource plant size: 77–78% for resource plants <2 m, 63% for 2–5 m, 36% for 8–15 m, and 0% for 70 m. Rooting percentages of cuttings collected from different individuals were not different for the 2–5 m tall class, while they were significantly different for the 8–15 m tall class. Resource plant size was negatively correlated with the number of roots for rooted cuttings. No significant relationship was observed between resource plant size and mean length of each root, total root length or total root dry weight for rooted cuttings. The results suggest the possibility of collecting cuttings from relatively large resource plants up to 15 m tall and >20 years old if we chose good individuals for resource plants. The results, however, show the difficulty in using reiterated branches of adult trees as a source of cuttings for D. lanceolata. Received: October 15, 2001 / Accepted: November 11, 2002 Acknowledgments We express our sincere thanks to Dr. S. Tamura, Dr. K. Ogino, and Mr. A.A. Hamid for their kind support. The tree tower was constructed in a cooperative project between Japan and Sarawak supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan (Grant NP0201). The cutting experiment was partly funded by the Nippon Life Insurance Foundation and the Japan Society for the Promotion of Science (JSPS-RFTF96R16001). Correspondence to:A. Itoh