The influence of wind on branch characteristics of Pinus radiata

Measurements taken from trees growing in exposed and sheltered areas within two structurally similar forests were used to investigate the influence of wind on branch characteristics of mature New Zealand-grown Pinus radiata. A widely used branch model was used to remove the influence of treatment and site differences in tree stem diameter and height, so that the influence of wind on branch diameter could be examined. At site 1 average windspeed in the exposed treatment exceeded average windspeed in the sheltered treatment by 62%. When averaged across sites, mean branch diameter, branch index (mean diameter of the largest branch, in each of the four azimuthal quadrants) and largest branch diameter in exposed areas significantly exceeded values for trees in sheltered areas by 9 mm (25%), 42 mm (54%), and 72 mm (72%), respectively. Treatment and site differences in tree stem diameter and height partially accounted for the observed increases in branch diameter. However, after these effects were removed by the model, branch diameter in exposed areas still significantly exceeded that in sheltered areas by 21 mm for branch index and 44 mm for the largest branch. Treatment and site variation in this residual branch diameter was almost entirely attributable to topographical exposure to 1 km, a variable which has been found to be strongly correlated to windspeed. Possible reasons for these observed wind-induced increases in branch diameter are discussed.

Effects of leaf and branch removal on carbon assimilation and stem wood density of Eucalyptus grandis seedlings

The rate of leaf CO₂ assimilation (A _l) and leaf area determine the rate of canopy CO₂ assimilation (A _c) can be thought proportional to assimilate supply for growth and structural requirements of plants. Partitioning of biomass within plants and anatomy of cells within stems can determine how assimilate supply affects both stem growth and wood density. We examined the response of stem growth and wood density to reduced assimilate supply by pruning leaf area. Removing 42% of the leaf area of Eucalyptus grandis Hill ex Maiden seedlings did not stimulate leaf-level photosynthesis (A _l) or stomatal conductance, contrary to some previous studies. Canopy-level photosynthesis (A _c) was reduced by 41% immediately after pruning but due almost solely to continued production of leaves, and was only 21% lower 3 weeks later. Pruning consequently reduced seedling biomass by 24% and stem biomass by 18%. These reductions in biomass were correlated with reduced A _c. Pruning had no effect on stem height or diameter and reduced wood density to 338 kg m⁻³ compared to 366 kg m⁻³ in control seedlings. The lower wood density in pruned seedlings was associated with a 10% reduction in the thickness of fibre cell walls, and as fibre cell diameter was invariant to pruning, this resulted in smaller lumen diameters. These anatomical changes increased the ratio of cross-sectional area of lumen to area cell wall material within the wood. The results suggest changes to wood density following pruning of young eucalypt trees may be independent of tree volume and of longer duration.     

Six-year field test results of micropropagated black cherry (Prunus serotina)

Summary A field test was established in 1987 to evaluate the growth of micropropagated black cherry plantlets and control seedlings. The study also evaluated effects of two container types on initial survival and growth and of pruning on stem form and growth. At the time of field establishment, plantlets had more extensive root systems than the control seedlings. Survival and height growth were not influenced by container size. Through the first three growing seasons, seedlings were larger than micropropagated plants, but growth differences diminished in the fourth through sixth seasons. Pruning increased the length of clear stem by nearly five-fold but adversely affected diameter growth. Although all clones were from ortet trees more than 50 yr old, none showed plagiotropic growth. Six-year results showed that in a well-prepared and maintained plantation, black cherry trees derived from tissue culture can have at least 80% survival, and growth rates in excess of 1 m per year.     

Topochemical investigation of early stages of lignin modification within individual cell wall layers of Scots pine (Pinus sylvestris L.) sapwood infected by the brown-rot fungus Antrodia vaillantii (DC.: Fr.) Ryv.

The initiation and progress of wood degradation of Pinus sylvestris sapwood exposed to the brown-rot fungus Antrodia vaillantii was studied on a cellular level by scanning UV microspectrophotometry (UMSP 80, Zeiss, MSP 800 Spectralytics). This improved analytical technique enables direct imaging of lignin modification within individual cell wall layers. The topochemical analyses were supplemented by light and transmission electron microscopy (TEM) studies in order to characterize morphological changes during the first days of degradation. Small wood blocks (1.5 × 1.5 × 5 mm) of Scots pine (P. sylvestris) were exposed to fungal decay by A. vaillantii for 3, 7, 11, 16, and 22 days. No significant weight loss was determined in the initial decay periods within three up to 7 days. After three days of decay the topochemical investigation revealed that the lignin modification starts at the outermost part of the secondary wall layer, especially in the region of the latewood tracheids. During advanced degradation after exposure of 22 days, lignin modification occurs non-homogeneously throughout the tissue. Even among the significantly damaged cells, some apparently unmodified cells still exist. Knowledge about lignin modification at initial stages of wood degradation is of fundamental importance to provide more information on the progress of brown-rot decay.     

How does the richness of wood-decaying fungi relate to wood microclimate?

Microclimatic conditions in dead wood influence fungal growth and hence also species composition, but it remains unclear how they influence species richness in nature. We analysed fungal species richness based on the occurrence of fruit bodies on 2 m long segments of both standing and lying trunks of Norway spruce (Picea abies). The number of non-red-listed species was related positively to moisture, and negatively to both temperature extremes and fluctuations. The numbers of both red-listed and non-red-listed species were further differently influenced by trunk diameter and by trunk properties related to the progression in wood decay. These results indicate that the richness of fungal communities in dead wood is shaped by an interaction of wood decay, moisture and temperature fluctuations.     

Radial stem variations of Tabebuia chrysantha (Bignoniaceae) in different tropical forest ecosystems of southern Ecuador

Stem diameter increments of the broadleaved deciduous tree species Tabebuia chrysantha were measured with high-resolution dendrometers in a tropical lower montane forest and in a dry forest in southern Ecuador, the latter showing a distinct dry season. Those analyses were complemented by wood anatomical studies on regularly collected microcores to determine the season of active cambial growth and the time of formation of annual growth boundaries. The length of the cambial active period varied between 3 and 7 months at the tropical lower montane forest and 2 and 4 months in the dry forest, respectively. During dry days, amplitudes of daily stem diameter variations correlated with vapour pressure deficit. During October and November, inter-annual climate variations may lead to dry and sunny conditions in the tropical lower montane forest, causing water deficit and stem diameter shrinkage in T. chrysantha. The results of the climate–growth analysis show a positive relationship between tree growth and rainfall as well as vapour pressure deficit in certain periods of the year, indicating that rainfall plays a major role for tree growth.     

A Comparison of Isozyme and Quantitative Genetic Variation in Pinus Contorta Ssp. Latifolia by F(st)

We employed F-statistics to analyze quantitative and isozyme variation among five populations of Pinus contorta ssp. latifolia, a wind-pollinated outcrossing conifer with wide and continuous distribution in west North America. Estimates of population differentiation (F(ST)) for six quantitative traits were compared with the overall estimate of the differentiation (F*(ST)) from 19 isozymes that tested neutral to examine whether similar evolutionary processes were involved in morphological and isozyme differentiation. While the F(ST) estimates for specific gravity, stem diameter, stem height and branch length were significantly greater than the F*(ST) estimate, as judged from the 95% confidence intervals by bootstrapping, the F(ST) estimates for branch angle and branch diameter were indistinguishable from the F*(ST) estimate. Differentiation in stem height and stem diameter might reflect the inherent adaptation of the populations for rapid growth to escape suppression by neighboring plants during establishment and to regional differences in photoperiod, precipitation and temperature. In contrast, divergences in wood specific gravity and branch length might be correlated responses to population differentiation in stem growth. Possible bias in the estimation of F(ST) due to Hardy-Weinberg disequilibrium (F(IS) & 0), linkage disequilibrium, maternal effects and nonadditive genetic effects was discussed with special reference to P. contorta ssp. latifolia.     

Wood decomposition in an abandoned beech and oak coppiced woodland in SE England

Stand structure and rates and patterns of wood litterfall, between 23 June 1977 and 27 June 1979, are described for two sites In a coppiced beech Fagus sylvatica L. and oak Quercus petraea (Mattuschka) Liebl. woodland in south-east England.
Total wood fall (excluding trunks) was estimated at 1264 kg ha⁻¹ and 593 kg ha⁻¹ for the two years of sampling at one site and 776 kg ha⁻¹ during the second year on the other site. The majority of leaf fall occurred in autumn; the maximum twig (wood < 1 cm diameter) and branch (wood ≥ 1 cm diameter) fall, occurred in winter at times generally corresponding with high wind speeds. Many oak twigs, however, abscissed in early November irrespective of wind speed.
Branch characteristics at fall (size, state of decay and bark cover) were documented. The most significant feature observed was that a large amount of decay frequently occurred in branches whilst still in the canopy.     

The conservation requirements of an endangered hoverfly, Hammerschmidtia ferruginea (Diptera, Syrphidae) in the British Isles

The saprophagous larva of the endangered hoverfly, Hammerschmidtia ferruginea (Fallén, 1817) (Diptera, Syrphidae) develops in wet, decaying sap under the bark of dead trees and branches of aspen, Populus tremula L. (Saliaceae). However this breeding site is transient: wet decay builds up patchily over 1.5–2 years of the tree or branch dying and lasts for a further 1–3 years before the bark falls off. Between 1990 and 2006, H. ferruginea swung through a cycle of abundance when the number of localities where it was detected dropped from 13 to 5 and back to 8. Fluctuations in amounts of dead wood caused by winds and storms probably explain this population swing. When there are few dead trees and branches, H. ferruginea breeds in sap flows on live P. tremula trees and populations are maintained but at low levels. To prevent local extinctions during periods when fallen wood is scarce, breeding habitat can be supplemented by felling trees and branches. Fallen wood with wet decaying sap is also important as an assembly site for mate selection. Adult food plants include flowers of bird cherry Prunus padus, rowan Sorbus aucuparia and hawthorn Crategus monogyna. Adults were recorded dispersing up to 1 km but are probably able to move further than this.     

长白落叶松半同胞家系生长和木材性状遗传变异与联合选择

长白落叶松（Larix olgensis）是我国东北重要的用材树种,根据生长和木材性状对其进行综合选择至关重要。本研究以吉林省延边自治区汪清林业局32年生的49个长白落叶松半同胞家系为材料,对其9个生长性状（树高、地径、胸径、3 m径、材积、尖削度、冠幅、分枝角和通直度）和4个木材性状（木材基本密度、管胞长度、管胞宽度和管胞长宽比）进行测定与分析。结果表明：不同变异来源间所有性状差异均达极显著水平（P<0.01）;各性状家系遗传力均较高（0.51~0.96）;表型变异系数为3.04%（分枝角）~23.15%（冠幅）;各性状相关系数为-0.367（管胞宽度与管胞长宽比）~0.994（胸径与材积）;主成分分析结果表明,4个主成分的累计贡献率达到78.46%,包含了家系生长性状和木材性状的大部分信息;分别以生长和木材性状对家系进行综合评价,初步筛选出5个生长性状优良家系（S78、S81、S80、S84和S83）和5个木材性状优良家系（S37、S51、S6、S30和S19）,结合生长和木材性状初步筛选出5个优良家系（S89、S74、S76、S82和S83）。本研究初选的材料可以为良种选育提供基础,亲本可以为改良种子园营建提供材料。     

Ciclo Di Accrescimento E Differenzazione Delle Gemme in Piante Perenni Nel Territorio Di Bari

Summary

The evolution of cambial activity during one year in Viburnum Tinus L. in Bari has been studied. The research seems to be particularly difficult in this evergreen shrub. The wood is of the porous diffused type with scarse evidence of wood rings. The vessel diameter varies rather irregularly in the wood ring; on the other side the fibers show wide variations and may be assumed as a good index of the wood ring evolution. Both in the branch and in the stem only one wood ring each year is formed.

Cambial activity prosecutes during the whole year, with an irregular step. During the period July-beginning of September the cambium devides very slowly, or possibly stops deviding.

The early wood is produced earlier in the branch than in the stem; namely in February-end of May in the branch and in March-beginning of June in the stem. The stimulating growth stuffs evidently proceeds downwards from the top to the base of the plant. The relations between ring evolution and climatic factors are discussed. The peculiar cambial poussée during the month of June seems to be correlated with the exceptionally aboundant rainfall of May in Puglia in 1947.

The late wood is formed during the other months discontinuosly. The alternation between the two phases of cambium division and wood lignification has been focussed. The wood ring in Viburnym Tinus is annual and the early wood differentiates in spring.     

How do trees grow? Response from the graphical and quantitative analyses of computed tomography scanning data collected on stem sections

Tree growth, as measured via the width of annual rings, is used for environmental impact assessment and climate back-forecasting. This fascinating natural process has been studied at various scales in the stem (from cell and fiber within a growth ring, to ring and entire stem) in one, two, and three dimensions. A new approach is presented to study tree growth in 3D from stem sections, at a scale sufficiently small to allow the delineation of reliable limits for annual rings and large enough to capture directional variation in growth rates. The technology applied is computed tomography scanning, which provides – for one stem section – millions of data (indirect measures of wood density) that can be mapped, together with a companion measure of dispersion and growth ring limits in filigree. Graphical and quantitative analyses are reported for white spruce trees with circular vs non-circular growth. Implications for dendroclimatological research are discussed.     

基于地基激光雷达的落叶松人工林枝条因子提取和建模

地基激光雷达(TLS)可以实现从森林中无破坏收集数据。本文基于地基激光雷达数据通过点云处理软件以人机交互的方式获取了26株落叶松样木的1266组枝条信息,包括着枝高度、弦长、枝长、着枝角度、基径和弓高。枝条可提取的最大相对着枝高度的平均值为0.83。在所提取的枝条因子中,提取精度依次为着枝高度＞弦长＞枝长＞基径(基径大于20 mm的枝条)＞弓高,将树冠分为4部分后分析发现,随着冠层高度的增加,枝条密度呈升高趋势,枝条提取率和提取精度呈下降趋势。此外,由于枝条基径提取精度较低,以弦长、着枝高度、胸径和树高为自变量构建基径预测模型。对不同基径的实测值、提取值与模型预测值对比分析发现,枝条基径的预测精度大于提取精度。对于造材来说,最有价值的部分是树木中下部,本方法能够较准确地提取树木胸径树高和相对着枝高度0.8以下的枝条属性信息,提供构建木材质量模型所需要的参数。     

Effects of root pruning on the growth and water use efficiency of winter wheat

A pot experiment was conducted to study the effects of root pruning at the stem elongation stage on the growth and water use efficiency (WUE) of winter wheat (Triticum aestivum). The results showed that stomatal conductance (g) and transpiration (E) of wheat were very sensitive to root pruning. After root pruning, they declined rapidly and but returned to pre-pruning values 15 days after treatment. Under well-watered conditions, there was no significant difference in leaf water potential (ψ_leaf) between root pruned and control plants after root pruning. Under moderate drought stress, ψ_leaf of root pruned plants declined significantly compared to the control 3 days after root pruning. After 15 days, ψ_leaf of root pruned plants was similar to the controls. Under different soil moisture levels, net assimilation rate (A) of root pruned plants was lower than controls 3–7 days after root pruning, but was similar to the controls 15 days after pruning. At anthesis (50 days after root pruning), root pruned plants showed significantly higher A compared with the control. Leaf area per tiller and tiller number of root pruning plants was significant lower than the control at booting stage, which showed that root pruning restrained the growth of plants in the early growing stage, but leaf area per stem, of root pruned plants, was similar to the control at anthesis. Under both soil moisture levels, there was no significant difference in grain yield between root pruned and the control plants in the monoculture. In mixture with the control plants, the root pruned plants was less productive and had a lower relative yield (0.92 and 0.78, respectively) compared with the control (1.13 and 1.19, respectively), which suggested that the pruned plants lost some of its competing ability and showed a lower ability to acquire and use the same resources in the mixture compared with the control plant. Over the whole growing cycle, root pruning reduced water consumption (by 10% under well-watered conditions and 16% under moderate drought stress) of wheat significantly compared to the control (P < 0.05), and but there was no significant difference in grain yield between root pruned and control plants. Therefore root pruned wheat had a higher WUE with respect to grain yield compared with the controls. In conclusion, lowering water consumption by root pruning in the early growing stage is an effective way to improve water use efficiency in arid and semi arid areas.     

Apical control of branch movements in white pine: biological aspects

Two-year-old branches on control trees (Pinus strobus L.) were compared through a season with branches on trees stem-girdled just above, or below, the branch whorl. All branches first sagged down for 20 days and then moved up for 40 days. Then, control branches reversed and moved back down while branches in both girdle treatments continued to move up. Movement reversal correlated with cessation of both elongation and diameter growth in control branches. Diameter growth continued in branches of girdled trees. Control branches continued to stiffen even after diameter growth stopped. Differences in movements due to girdling are from compression wood formed after cessation of branch elongation. Apical control stops cambial activity and compression wood formation in branches after branch elongation ceases, allowing photosynthate produced in the branch to move to the stem. Control branches bend down from increasing self-weight after cambial activity ceases.     

Control of postharvest decay on cherry tomatoes by marine yeast Rhodosporidium paludigenum and calcium chloride

Aims: In this study, the potential of calcium chloride (CaCl₂) application to improve the efficacy of the marine antagonist Rhodosporidium paludigenum in controlling postharvest diseases of cherry tomatoes was assessed. Methods and Results: CaCl₂ alone was found not to have any direct influence on the population growth of R. paludigenum in NYDB cultures or in cherry tomato wounds. However, the combined treatments with 1 × 10⁸ cells ml^?1R. paludigenum and CaCl₂ at the concentration from 0·5 to 2% showed high activities to reduce black rot caused by Alternaria alternata in cherry tomato wounds, significantly higher than those of R. paludigenum or CaCl₂ alone. Meanwhile, 0·5% CaCl₂ in combination with 1 × 10⁸ cells ml^?1R. paludigenum greatly inhibited the natural decay of cherry tomatoes in 21 days’ storage at 25°C. Conclusions: The combination of R. paludigenum and CaCl₂ enhances the inhibition of black rot and natural decay of postharvest cherry tomatoes. The results from this study provide a new way to improve the efficiency of R. paludigenum in maintaining the quality of postharvest fruits and vegetables. Significance and Impact of the Study: The marine yeast R. paludigenum combined with CaCl₂ has greatly potential use as an alternative to chemical fungicides in inhibiting postharvest decay on cherry tomatoes.     

SURFACE AREA RELATIONS OF WOODY PLANTS AND FOREST COMMUNITIES

Surface area of wood and bark is an important dimension of forests, with implications for respiration rate, energy exchange, and water and mineral budgets. Surface area of stem wood and bark can be estimated effectively from linear regressions on conic surface (one-half basal circumference times tree height) or from regressions of the logarithm of area on the logarithm of diameter at breast height. Branch surface can be estimated from a formula using branch basal diameter, length, and number of current twigs, and from logarithmic regressions of branch bark surface on basal diameter of branches and breast-height diameter of trees. In temperate deciduous forests several square meters of plant surface occur above each square meter of ground surface; these plant surfaces include 0.3–0.6 m² of stem bark, 1.2–2.2 m² of branch bark, and 3.0–6.0 m² of leaf blades. Branch bark surface increases more rapidly than leaf surface with increasing size of branches and trees. Growth and aging of trees, and maturation of forests, imply increasing ratios of bark (and wood) surface to the photosynthetic leaf surface which supports its growth and respiration.     

Selection perspectives for genetic improvement of wood stiffness in hybrid larch (<Emphasis Type="Italic">Larix</Emphasis> x <Emphasis Type="Italic">eurolepis</Emphasis> Henry)

Genetic variability of modulus of elasticity (MOE) was investigated in three genetic trials, including two progeny (16 years old) and one clonal (19 years old) trials of hybrid larch (Larix x eurolepis Henry). MOE was directly assessed on standing trees using the Rigidimeter, a bending device, and related to other traits including height, BH diameter and wood density. Mean MOE ranged from 5,183 to 9,228 MPa among families in the progeny trials and from 4,591 to 11,486 MPa in the clonal trial. Among traits studied, MOE was one of the most variable traits. It was strongly and positively related to wood density at both the individual and genotype mean levels. Interestingly too, wood stiffness did not seem, or only weakly, unfavourably linked to stem diameter at the phenotypical level, but it was negatively or not correlated to diameter at the genetic level. As well, MOE showed a high GxE stability over the two progeny trial sites. Narrow-sense heritabilities for MOE were moderate (around 0.36). In all three trials, they were lower than those for wood density or total height, and of the same level as for diameter. Improvement of wood stiffness of hybrid larch using the Rigidimeter seems possible and promising genetic gains are expected. Impacts of selection for growth traits on MOE are also discussed.