Termite resistance and color of heartwood of hinoki (Chamaecyparis obtusa) trees in 5 half-sib families in a progeny test stand in Kyushu, Japan

Hinoki (Chamaecyparis obtusa) wood has been used as a structural material in Japan because of its superior mechanical properties, its excellent durability and the beautiful color of its heartwood. Variations of termite resistance and compositions of extractives among hinoki trees have been reported. However, genetic variation of termite resistance and the effect of heartwood color on termite resistance remain unknown. In this study, we report the characteristics of termite resistance and color indexes (L*, a* and b*) of heartwood of hinoki half-sib families in a progeny test stand. The survival days of termites and the mass loss of samples of hinoki heartwood differed significantly among hinoki families. Families with red-color heartwood had larger termite resistance than families with yellow-color heartwood. The termite resistances of individual samples from two families with yellow-color heartwood were as small as that of Pinus densiflora. Larger a* and smaller b* induced larger termite resistance of heartwood. The effect of DBH (diameter at breast height) of hinoki trees on termite resistance of hinoki families was small.     

Ethylene production and premature senescence of needles from fir trees (Abies alba)

Measurements of ethylene production, free and conjugated ACC concentrations, chlorophyll content, and length of needles from fir trees (Abies alba Mill.) growing in stands affected by “Waldsterben” showed that during the development of the disease two consecutive stages can be distinguished: a. long-term, low ethylene production and accumulation of conjugated ACC (MACC) in response to chronic stress, associated with reduced needle growth, and b. high ethylene production associated with chlorophyll breakdown, followed by premature abscission of the needles.     

Microfibril angle and density of hinoki (Chamaecyparis obtusa) trees in 15 half-sib families in a progeny test stand in Kyushu, Japan

It was previously believed in Japan that the wood qualities of hinoki (Chamaecyparis obtusa) were superior to sugi (Cryptomeria japonica). However, few studies of wood properties such as MFA (microfibril angle of S₂ layer in secondary wall of tracheid) have been completed for hinoki. Some reports have found that hinoki plus tree families have similar mechanical properties to sugi. Here we report the characteristics of MFA and density of hinoki half-sib families in a progeny test stand. There were significant differences in MFA and density between families. The wood properties of two families, Nakatsu 3 and Kanzaki 5, are stable in radial pattern and suitable for structural use. Early selection of hinoki families by MFA and density may be difficult. Effects of MFA and density on E _d (dynamic modulus of elasticity) of logs differed between families. The effects of growth rate on MFA and density differed between families and also between juvenile and mature wood. The faster growth rate in Nakatsu 3 appeared to improve wood properties and increase E _d of logs, although in many other families, faster growth rate had negative effects on desirable wood properties for structural use.     

Variability of selected wood characteristics in 40 half-sib families of black spruce (Picea mariana)

Summary Based on 15-year-old black spruce (Picea mariana) trees from 40 half-sib families sampled from 9 blocks of a family test in New Brunswick, this study examined intertree and intratree variation in various wood density and ring width characteristics. Of various variance components of the intertree variation, a remarkable variance component due to family was found in wood density characteristics (viz. average wood density, average earlywood density and latewood density of the tree), and these characteristics are thus under strong genetic control (h _i ² ranging from 0.60 to 0.86, and h _f ² from 0.56 to 0.68). It, to a lesser extent, applies to ring width characteristics at the tree level (viz. average ring width, and average earlywood width, latewood width and latewood percent of the tree) that show a lower heritability (h? from 0.18 to 0.28, and h _f ² from 0.22 to 0.36). Both block and block × family interaction contribute little to the total intertree variation encountered in 40 families from 9 blocks, while tree-to-tree variation within the family accounts for most (over 3/4) of the total intertree variation.Compared to the intertree variation (tree-to-tree variation within the family), the intratree variation in various wood characteristics studied is considerably larger in this species. It appears that most intraring wood density characteristics show a relatively smaller intertree variation but a relatively larger intratree variation as compared to ring width characteristics (except latewood width and latewood percent). Latewood width and latewood percent show the smallest intertree variation and the largest intratree variation. Between the two sources of the radial intratree variation, cambial age explains much more variation in most intraring wood density characteristics, while ring width accounts for more variation in earlywood width, latewood width and intraring density variation. This indicates that wood density of growth rings in this species is dependent more on cambial age than ring width (growth rate). Among various wood density and ring width characteristics studies, maximum (latewood) density shows the strongest response to calendar year. This characteristics is thus a useful dendroclimatic parameter in this species.I would like to thank Dr. E.K. Morgenstern and Mr. D. Simpson for their involvement in the planning of this study. Thanks are also due to G. Chauret, T. Keenam, R. Ploure, V. Steel and C. Reitlingshoefer for their technical assistance     

Heritability of shoot die-back and root biomass in sixteen Pterocarpus angolensis (Fabaceae) half-sib families from Malawi,Namibia and Zambia

The experiment was conducted to ascertain narrow-sense heritability (h ²) and the family-within-provenance variation in shoot die-back, taproot length and root biomass of half-sib Pterocarpus angolensis families from Malawi, Namibia and Zambia. Provenances differed significantly in shoot die-back for both shoot die-back seasons. A within provenance family effect was not significant in the first shoot die-back season but was significant in the second shoot die-back season. An increase in proportion of seedlings dying back, to 91%, for a Malawi family was observed in the second shoot die-back season. Provenance and within provenance family effects may be due to latitudinal differences between the provenances. The h ² of shoot die-back was 0.07 (SE = 0.07) in the first shoot die-back season and 0.42 (SE = 0.27) in the second shoot die-back season. Narrow-sense heritability for root biomass was 0.81 (SE = 0.45). The h ² for the second die-back season and root biomass suggest the traits are heritable. Random selection of individual families for assessing shoot die-back is important since this trait is only restricted to seedlings and saplings and not mature trees. Within provenance family effects for root biomass were significant, indicating differences between families. Two families from the most northerly provenances of Phalombe and Skull Rock in Malawi were significantly different from other southern families. Non-significant phenotypic correlation between shoot die-back and root biomass shows that shoot die-back is not likely to be determined by root size nor taproot depth. Although a non-significant negative phenotypic correlation (–0.15) between the second shoot die-back season and root biomass was obtained, a family from Malawi that had the highest mean shoot die-back in the second shoot die-back season had the smallest root biomass. Half-sib families with post shoot die-back growth potential, in the first shoot die-back season, are likely to have a better chance of post shoot die-back growth later.     

7个造林树种对重金属污染的吸滞能力评价试验

通过杞柳、水杨梅等7个造林树种的造林试验,测定了各树种1年生根部组织内Hg、Cd、Ni、Cr、Cu、Mn、Zn、Pb和As等9种重金属指标的含量。测定结果显示：7个树种对重金属均有一定的吸滞能力,其中杞柳对所有测定的重金属均有较强的吸滞能力,其他树种对不同重金属指标吸滞能力表现不一。通过综合吸滞能力评价,按CI值将7个树种的综合吸滞能力种排序：杞柳〉池杉〉垂柳〉落羽杉〉湿地松〉水杨梅〉杨树。     

Salinity effects and differential germination of several half-sib families of baldcypress from different seed sources

Saltwater intrusion is responsible for the destruction of large expanses of baldcypress swamps along the Gulf of Mexico in the southern United States. Recent restoration efforts have focused on the identification, and subsequent planting, of moderately salt-tolerant plant material within these ghost forests. The long-term persistence of cypress swamps in these areas, however, will ultimately depend on the germination of seeds from the improved parent trees. This study investigates the germination capacity of seeds collected from baldcypress parent trees, located in both freshwater and brackish water environments. Seeds were tested at four different salinity levels under controlled conditions for a period of 65 days. Mean germination under the 0, 2, 4, and 6 g l^-1 seawater treatments was 26.3, 22.9, 15.4, and 10.2%, respectively. Although none of the eight families used in this study had a germination greater than 50%, three families demonstrated superiority in their germination capacity under all four salinity treatments. In general, brackish water seed sources had greater germination success than the two families from freshwater sources. Results indicate that families previously identified as moderately salt-tolerant based on physiological and morphological parameters may be equally successful in seed germination capacity under moderately saline conditions.     

Root and butt rot of Todo fir (Abies sachalinensis) caused by Heterobasidion annosum s.l. in Hokkaido,Japan

The occurrence and symptoms of root and butt rot were examined in a 35 × 30 m plot of 68‐year‐old Todo fir plantation in Hokkaido, Japan. Forty‐seven percent of the cut stumps were decayed and 52% of the decayed stumps showed similar decay characteristics with yellowish orange to light brown colouration and expanded pockets in the heartwood. Morphological characteristics of the pure cultures isolated from the decay were similar to the cultures isolated from basidiocarps of Heterobasidion annosum sensu lato, found on fallen logs outside of the research site. Also DNA analysis based on the combined data set of three gene loci (glyceraldehyde 3‐phosphate dehydrogenase, heat shock protein 80–1 and elongation factor 1‐alpha genes) showed that the isolates from the decay are included in the same clade with the Japanese H. annosum s.l. isolates. They form a subclade to H. parviporum (the European S group of H. annosum s.l.). This is the first report of molecular determination of H. annosum s.l. isolated from root and butt rot in a plantation in Japan.     

The distribution of closely related large genets of Heterobasidion parviporum in a Todo fir (Abies sachalinensis) stand in Hokkaido,Japan

The distribution of genets of a root and butt rot pathogen Heterobasidion parviporum was studied in a 68‐year‐old Abies sachalinensis plantation in Japan. A total of 33 pure cultures of H. parviporum were isolated from diseased Todo fir stumps after clear‐felling. Individual genets of the fungus were identified by three different methods: somatic incompatibility test, random amplified polymorphic DNA, and DNA microsatellite analyses. The combined results of the three analyses identified at least eight genets within a 60 × 100 m plot. One genet, consisting of only one isolate, was genetically differentiated from the other genets by all three methods; the other 32 isolates, however, were grouped with minor discrepancies, into seven genetically close genets. The genetic differentiation was lower than that recorded previously in Europe. A single genet infected 1–15 trees in the plot. The longest distance of the two most isolated trees of a single genet was 51 m. The close genetic relationship between genets and their large sizes suggest that basidiospores from restricted sources (just a few fruiting bodies) infected the site before establishment of the present Todo fir stand and that the disease has spread mainly by vegetative growth of the mycelia through root contact. Absence of fruiting bodies of the fungus in the study plot also suggests the greater importance of vegetative growth than spore dispersal for the spread of this fungus.     

Pathogenicity of Phytophthora species and Pythium undulatum isolated from Abies procera Christmas trees in Ireland

Phytophthora cryptogea, Phytophthora cinnamomi, Phytophthora cambivora, Phytophthora megasperma and Pythium undulatum were isolated from diseased Noble fir (Abies procera) seedlings and soil associated with dead Noble fir in Ireland. Seedlings of four Christmas tree species (A. procera, Picea sitchensis, Picea abies and Pinus contorta) were inoculated with these oomycetes to test their pathogenicity and the susceptibility of the various tree species. Phytophthora spp. and Pythium undulatum caused root rot on all tree species. Disease symptoms included reddish brown cambial discoloration, crown symptoms, brown foliage, dark brown roots, root rot and seedling mortality. These symptoms were similar to those observed on Noble fir in naturally infested plantations. Pythium undulatum appeared as the most virulent pathogen followed by P. cinnamomi, P. cambivora, P. megasperma and P. cryptogea. Noble fir showed to be most susceptible and lodgepole pine most tolerant while Sitka spruce and Norway spruce were intermediate.     

秃杉半同胞家系生长性状的遗传分析及初选

通过对从云南昌宁、云南龙陵引进的17个秃杉半同胞家系实生林的长期观测,进行了秃杉生长形状的遗传分析及初步选择。结果表明:各半同胞家系在第5、15、24年,生长性状差异达到显著水平以上,这些差异主要由其本身的遗传特性决定,受中、强遗传力的控制,而受环境控制较弱。所有半同胞家系中,24年生14号、2号、17号、16号的树高、胸径和材积的均值分别为13.64 m、18.29 cm和0.1877 m^3,遗传增益的平均值分别为5.2%、4.38%和15.85%;选择出6株优良个体,24年生树高、胸径和材积的平均值分别为17.6 m、29.12 cm和0.5886 m^3,遗传增益的平均值分别为14.13%、14.73%和69.83%,这些优良半同胞家系和优良个体表现出突出的生长优势,可作为种子园和采穗圃材料。     

Vibrational properties of wetwood of todomatsu (<Emphasis Type="Italic">Abies sachalinensis</Emphasis>) at high temperature

The object of this study was to understand precisely the drying characteristics of wetwood of todomatsu (Abies sachalinensis Mast.). For this purpose, the vibrational properties of wetwood of todomatsu at high temperature were compared with those of normal parts that had lower green moisture content than the wetwood. Specimens were cut respectively from the wetwood and normal parts, and matched in the radial direction. The specimens and the measuring systems were placed in an electric drying oven and free-free vibration tests were conducted in the oven under absolutely dry conditions. The wetwood and the normal parts were tested separately. The temperature was raised from room temperature to 200°C and then lowered to 50°C in steps of 25°C. The specific Young’s modulus decreased with an increase in temperature during the heating process while it increased with the decreasing temperature during the cooling process. There was no significant difference in the specific Young’s modulus between the wetwood and the normal part at all tested temperatures. The loss tangent took a minimum value at about 100°C in both the heating and cooling processes. There was no significant difference in the loss tangent between the wetwood and the normal part. Thus, the elastic and viscoelastic behaviors of the wetwood appear to be similar to those of the normal part in the temperature range of an actual kiln-drying process.     

引种日本落叶松原生种源及优树半同胞家系苗期试验初报

引种日本落叶松原生种源及优树半同胞家系苗期试验研究结果表明：原生种源问高生长具有明显差异,确定松本、伊那、日光为优良种源;家系间的高生长也具有明显差异,确定县诹访１号等２０个家系为优良家系;原生种源的遗传变异幅度极大,具有相当的遗传改良潜力和遗传资源保存价值。     

Family variation in gas exchange, growth and leaf traits of black locust half-sib families

Variations in several growth, gas exchange and leaf traits among greenhouse-grown black locust (Robinia pseudoacacia L.) seedlings from 11 half-sib families were investigated. Three weeks after germination, early growth rates ranged from a minimum of 1 cm d(-1) in the slowest growing family, to a maximum of 3 cm d(-1) in the fastest growing family. Significant family variation in net photosynthetic rate per unit leaf area (P(N)), stomatal conductance, chlorophyll content, height, diameter, stem dry weight and total dry weight was observed. Net photosynthetic rate declined with seedling age. Net photosynthetic rate per unit leaf area was significantly correlated (r < 0.4) with specific leaf area, total chlorophyll, root dry weight, foliage dry weight and total dry weight. The correlation coefficients were higher (r >/= 0.55) between P(N) x total leaf area and growth traits (height, stem dry weight, foliage dry weight and total dry weight). The study indicated that variation in leaf area among the families was one reason for the lack of a strong relationship between P(N) and growth.     

Changes in shoot properties in relation to vertical positions within the crown of mature canopy trees of Abies mariesii and Abies veitchii

We investigated current shoot properties in two contrasting vertical positions (leader crown; LC, and lower branch; LB) within the crowns of mature trees of two subalpine conifer species, Abies mariesii and A. veitchii. For both LCs and LBs, shoot length decreased with increasing branching order. However, shoot properties were different between LCs and LBs. Shoots in LCs had more needle biomass per unit of shoot length. Shoots in sunny conditions pack needles closer along the shoot and intercept incoming light more completely. This causes the shoots in the LCs to have more needles. In contrast, less needle packing per unit shoot length in LBs results in the avoidance of mutual shading among needles in order to intercept limited light more effectively. Because branch systems in lower layers tend to be more shaded, the quantity of irradiance received by the shoots in LBs is smaller. Thus, reduced needle amounts on the shoots in LBs reflect the needle arrangement acclimating to the lower light availability. This study suggests the importance of changes in the properties of individual shoot as a component of a branch system and accordingly a whole-crown system in mature canopy trees of A. mariesii and A. veitchii.     

Accuracy of the Rotfinder instrument in detecting decay on Norway spruce (Picea abies) trees

Rotfinder is a non-destructive decay-sensing apparatus based on resistance measurements in standing trees. The accuracy of Rotfinder in detecting decay was evaluated in 500 standing trees in three Norway spruce (Picea abies) plots. Trees were measured at three heights, 0.30, 0.66 and 1.30 m. Sections were later inspected for the presence of decay and reaction zones. Inspected trees were mostly infected by Heterobasidion annosum and showed a large variation in the amount of decay present, ranging from 0.1% to 88.0% of the section. Correctly and incorrectly classified trees were compared in terms of ion and element concentration, density and moisture. Measurements at stump level (0.30 m) were more accurate than measurements at breast height (1.30 m) where the reaction zone and decay columns showed lower moisture content. The accuracy of Rotfinder increased when trees with small decay columns were regarded as ‘non-decayed’. When only trees with more than 15% of the section decayed were regarded as ‘decayed’, Rotfinder had an accuracy of 0.86 when performing assessments at stump level. False negatives, as opposed to true positives, corresponded to trees with smaller and drier decay columns, drier reaction zones and lower K⁺ (potassium) concentration in the decay column. False positives corresponded to trees with large sapwood and high sodium content in the sapwood. Rotfinder represents an alternative to the standard method of using increment core observations to assess decay in living trees.     

Interstock-induced mechanism of increased growth and salt resistance of orange (Citrus sinensis) trees

Interstocks improve the growth and salt resistance of lemon (Citrus limon (L.) Burm. f.) trees, but their effects on orange (Citrus sinensis (L.) Osbeck) trees are unknown. We grew 'Cleopatra' mandarin (CM) seedlings, budded trees of 'Salustiano' orange (SAO) on CM, 'Valencia Late' orange (VLO) on CM (VLO/CM), and interstock trees VLO/SAO/CM in pots of sand watered with nutrient solution containing 5 (control) or 50 mM NaCl for 12 weeks. Plants were harvested on six successive occasions and the time trends in relative growth rate (RGR) and its components were estimated by fitting a Richards function regression to the harvest data. At low and high salinities, the VLO/SAO/CM combination had higher mean RGR than VLO/CM. Under control conditions, the increase in RGR caused by the interstock was the result of an increase in leaf mass fraction (LMF; leaf dry mass/plant dry mass ratio). Increases in net assimilation rate on a leaf mass basis (NARm) and LMF contributed equally to the increase in RGR in saline conditions, their growth response coefficients being 0.52 and 0.48, respectively. The structural modifications, specific leaf area (SLA) and leaf area ratio (LAR; leaf area:plant dry mass ratio), had a slight influence on the reduction in RGR by salinity. However, NARm had a large influence on RGR, except in CM. The interstock-induced mechanism increased biomass allocation to the assimilatory organs and, under saline conditions, increased Cl- and Na+ allocations to roots. Thus, the flux of ions to the leaves was either delayed or reduced or both. The dilution of imported ions by foliar growth reduced ion concentrations in leaves, resulting in higher NARm, which together with higher LMF, increased RGR.     

Carbon and biomass partitioning in balsam fir (Abies balsamea)

Balsam fir (Abies balsamea (L.) Mill) was extensively sampled to investigate the effects of forest management practices, site location, within-crown position, tree component (i.e., stem, foliage, branches and roots), and tree social classes on biomass and carbon (C) partitioning at the individual tree level and across ecological regions. The sites were located in three ecologically distinct forest regions of west-central New Brunswick, Canada. There were no significant differences in %C content of trees across ecological regions or across tree social classes. However, at the individual tree level, significant differences were evident in biomass and C allocation between different parts of the tree, between treatment types (i.e., unmanaged and pre-commercially thinned stands) and between within-crown positions, indicating the need for separate estimates of biomass and C content of tree components to obtain more precise estimates of quantities at the stand level. Calculating stand C content based on constant allocation values, as is commonly done, produced errors of up to 15% compared with the values calculated in this study. Three allometric equations of biomass and C that account for partitioning among different parts of the tree were developed and compared: (1) a third-order polynomial, (2) a modified inverse polynomial and (3) a modified Weibull equation. Diameter at breast height (DBH) was used as the only explanatory variable to describe fresh biomass, dry biomass and C content. All regressions derived showed a high correlation with DBH, with most r2 values > 0.95. A comparison of the equation results showed that the modified Weibull equation gave consistent results with the best overall fit and was the simplest of the three equations investigated. The regressions can be used to estimate forest biomass and tree C content at the stand level, given specific information on DBH.     

Improvement in growth and salt resistance of lemon (Citrus limon) trees by an interstock-induced mechanism

Interstocks can reduce toxic ion accumulations in leaves of budded citrus trees, but the mechanism is not understood. We grew sour orange (Citrus aurantium L.; SO) seedlings, budded trees of 'Salustiano' orange (Citrus sinensis L. Osbeck; SAO) on SO, 'Verna' lemon (Citrus limon L. Burm. f; VL/SO) and interstock trees (VL/SAO/SO) in pots of sand watered with nutrient solution containing 5 (control) or 50 mM NaCl (saline treatment) for 12 weeks. Plants were harvested in six successive harvests and time trends in relative growth rate (RGR) and its components were estimated by fitting a Richards function regression to the harvest data. The VL/SAO/SO trees in saline conditions had higher mean RGR than VL/SO trees in control conditions. Increases in both net assimilation rate on a leaf mass basis (NARw) and leaf mass fraction (LMF) contributed equally to a twofold increase in RGR of VL/SAO/SO trees in saline conditions. In control conditions, the increase in RGR caused by the interstock had growth response coefficients of GRC(NARw) = 0.20 and GRC(LMF) = 0.80. Structural modifications-specific leaf area, leaf area ratio and LMF-had a slight influence on the salt-induced changes in RGR, whereas NARw had a large influence. Salinity decreased root mass fraction (RMF) and increased stem mass fraction (SMF). In contrast, the interstock decreased SMF and increased LMF and RMF. The VL/SAO/SO trees had the highest RMF and proportionally higher Cl- and Na+ allocations in roots than the other plant types. In saline conditions, reductions in leaf ion transport rate and dilution of imported ions by foliar growth nearly halved ion accumulations in leaves of VL/SAO/SO trees.