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.     

Influence of non-genetic factors on yield of monoterpenes in leaf oils of Eucalyptus camaldulensis

Sources of variation in yields (as a fraction of leaf weight) of 1,8-cineole, -pinene, -pinene and limonene in the leaf oils of young Petford Eucalyptus camaldulensis trees were studied. The oil yields of leaves up to 5 months of age were significantly affected by physiological changes associated with leaf maturation. The extent of these changes depends on genotype and on external influences such as soil moisture conditions. Prolonged drought stress reduced oil production in young leaves but did not affect greatly the equilibrium reached between synthesis and removal of oils at leaf maturity. Waterlogging prolonged peak oil production.Trends in oil yields with time differed markedly between individual trees. Although genotypic variation was great, there was detectable variation attributable to site, season and year. A relationship between seasonal patterns and climatic factors could not be established. Part of the observed variation in oil yields with time was attributable to variability in leaf maturity.The relative superiority in oil-yielding capacity of certain individuals in each experiment was maintained throughout, despite substantial variation from non-genetic sources. This consistency in ranking is of advantage to tree breeders wishing to make selections amongst plantations of differing age, on different sites and at different times of the year. However, even with careful sampling controls, absolute values will vary substantially and progeny testing will be necessary to further assess the potential of the initial selections.     

Dry matter production and allocation in Eucalyptus cloeziana and Eucalyptus argophloia seedlings in response to soil water deficits

Effects of soil water availability on seedling growth, dry matter production and allocation were determined for Gympie (humid coastal) and Hungry Hills (dry inland) provenances of Eucalyptus cloeziana F. Muell. and for E. argophloia Blakely (dry inland) species. Seven-month-old seedlings were subjected to well-watered (100% field capacity, FC), moderate (70% FC) and severe (50% FC) soil water regimes in a glasshouse environment for 14 wk. There were significant differences in seedling growth, biomass production and allocation patterns between species. E. argophloia produced twice as much biomass at 100% FC, and more than three times as much at 70% and 50% FC than did either E. cloeziana provenance. Although the humid provenance of E. cloeziana had a greater leaf area at 100% FC conditions than did the dry provenance, total biomass production did not differ significantly. Both E. cloeziana provenances were highly sensitive to water deficits. E. argophloia allocated 10% more biomass to roots than did E. cloeziana. Allometric analyses indicated that relative biomass allocation patterns were significantly affected by genotype but not by soil water availability. These results have implications for taxon selection for cultivation in humid and subhumid regions.     

Relationships between nursery practices and field performance for Eucalyptus plantations in Brazil

The 3.5 million ha of Eucalyptus plantations in Brazil support many domestic and industrial activities. In the pulpwood sector, forest productivity has increased from 12 to 40 m³ ha^–1 year^–1 through breeding and silviculturalpractices. Nurseries have fostered thisevolution with changes in container/substratetypes, propagation methods and specificinfrastructure for each plant growth phase.Eucalyptus plants are mainly produced bycuttings, using rigid tube containers filledwith vermiculite-organic compound substrates.Stock quality is based on morphologicalcharacteristics of the plants, andenvironmental conditions are highly significantfor plant performance. Performance is dependenton physiological short-term effects related tosurvival and long-term effects of genotype/rootmorphology related to tree development. Currentsilvicultural trends are reducing establishmentcosts but increasing the risk of using lowquality plants. The development of fieldperformance models and nursery physiologicaltests is recommended for Eucalyptusplantations in Brazil. Improved experimentaldesigns are needed to capture the interactionbetween plant quality and field performance.     

Structural conversion of the lignin subunit at the cinnamyl alcohol stage in Eucalyptus camaldulensis

The lignin biosynthetic pathway in Eucalyptus camaldulensis was investigated by feeding stems with deuterium-labeled precursor. Pentadeutero[,-D₂ OCD₃] coniferyl alcohol was synthesized and supplied to shoots of E. camaldulensis, and incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry. In addition to the direct incorporation of labeled precursor into the guaiacyl unit, a pentadeuterium-labeled syringyl unit was detected. This finding indicates that the -deuterium atoms in the hydroxymethyl group of labeled coniferyl alcohol remain intact during modification of the aromatic ring. The relative level of trideuterium-labeled syringyl monomer (the result of conversion via the cinnamic acid pathway) was negligible, suggesting that the pathway at the monolignol stage is used for conversion of exogenously supplied precursor. Our results provide conclusive evidence of a novel alternative pathway for generation of lignin subunits at the monolignol stage even in plants that do not accumulate coniferin in lignifying tissues.     

Herbicides and planting date affect early performance of container-grown and bare-root loblolly pine seedlings in Alabama

The survival of bare-root and container-grown loblolly pine (Pinus taeda L.) seedlings exceeded 90% when outplanted in March at two sites in Lee County, Alabama. At both sites, soil moisture and seedling survival were greater in March than in May. A March herbicide application reduced weed biomass by 75–80% at both sites. At the moist site, herbicide application did not affect survival. However, at the drier site, a reduction in weed biomass increased both the percent soil moisture and the survival of May-planted bare-root seedlings. When soil moisture at planting time was less than 13% on a dry weight basis container-grown seedlings survived better than bare-root seedlings. At both sites, reduced weed competition resulted in greater seedling heights and diameters.Alabama Experiment Station Journal Series No. 9-85802.     

Species diversity in Eucalyptus camaldulensis woodlots and miombo woodland in Northeastern Zimbabwe

The tree species diversity, groundvegetation species richness, and soilcharacteristics were studied forEucalyptus camaldulensis woodlots and thenatural miombo woodlands in the Mukarakate Areaof Northeastern Zimbabwe. The woodlandcharacteristics were measured and soil sampleswere taken at a total of thirty-four miombowoodland plots and twenty-seven eucalyptusplantations.The number of tree species was significantlyhigher for the miombo woodland sites than forthe eucalyptus woodlots. The Berger-Parker andShannon-Wiener Index values for speciesdiversity were higher for the tree speciesfound on the miombo woodland sites. There wereno significant differences between theeucalyptus woodlots and the miombo woodlands inthe percentage of grass cover and the number ofgrass and herb species. The same grass and herbspecies were common in both the woodlots andthe woodlands. The older woodlots hadsignificantly more tree and herb species thanthe younger woodlots.Soil nutrient analyses showed no significantdifferences between the woodlots and thewoodlands regarding their available phosphorusand total nitrogen, but the total phosphorusand total carbon were higher for the miombowoodlands. The results suggest that E.camaldulensis woodlots established in areasthat were formerly fields and grazing areas inthe savannah-like conditions pertaining inSouthern Africa do not cause the loss ofspecies richness or soil nutrients. In heavilydeforested areas eucalyptus woodlots may evencontribute positively to the protection andpreservation of indigenous trees species andother flora.     

Eucalyptus plantations in Israel: an assessment of economic and environmental viability

This paper discusses a plantation management approach involving a combination of “short” and “long” rotations designed to allow farmers to receive income from trees as soon as possible after establishment. We present results from two plots that represent extreme conditions: (a) a seasonally waterlogged, non-saline site (Nahalal), and (b) a saline site (Ginnegar) located in the Yizre’el Valley, Israel. Six improved seed sources, four of Eucalyptus camaldulensis and two of E. occidentalis, were examined. The local Israeli seed source of E. camaldulensis (HA) performed best at both sites. In Nahalal, the short rotation thinning of the slower growing (50%) plantation trees could provide economic returns approximately five years after establishment. The calculated mean annual increment (MAI) of these trees reached 12.2 t ha⁻¹ year⁻¹. The long rotation, or better performing half of the plantation trees, could be used as a source of sawn timber, providing higher-value products. By nine years after establishment, the average DBH of the various seed sources reached 25.8 ± 1.9 cm. The calculated MAI of the combined cutting rotations reached 48.3 t ha⁻¹ year⁻¹. Eucalyptus grown under the combined (short- and long-term) management approach at Nahalal was more profitable than many other non-irrigated local crops. Eucalyptus production in Ginnegar would be less profitable than in Nahalal. However, an additional ecological benefit was provided by the crop’s ability to lower the water table. When this contribution to regional drainage is taken into account, trees become economically competitive with other non-irrigated field crops under saline conditions. Jim Morris–Deceased.     

Effect of NaCl and high pH on seedling growth of 15 Eucalyptus camaldulensis Dehnh. provenances

Eucalyptus camaldulensis Dehnh. is a moderately salt-tolerant Australian tree species widely used in farm forestry, often in salt-affected landscapes. In a glasshouse experiment, E. camaldulensis seedlings from 15 wide-ranging Australian seed sources (provenances), were cultured in sand-filled pots and treated for 57 days with control (no added NaCl in tap water, neutral pH), saline (150 mol m^–3 NaCl, stepped high pH (pH 7.6 to 9.5) and combined NaCl and high pH solutions. Significant differences were found among provenances in height and shoot dry weight. Differences in provenance response to treatment were found for dry weight but not for height. Reductions in shoot dry weight due to NaCl and high pH ranged from 42.9% to 82.0% and 4.3% to 51.7% respectively. Provenances from Lake Hindmarsh-SE (Victoria) and Lake Albacutya-N (Victoria) had relatively high tolerance to both stresses whereas those from Lake Albacutya-S (Victoria), Lowan Valley (Victoria), Silverton (New South Wales) and Katherine (Northern Territory) had low tolerance to both stresses. Provenances from De Grey River and Fitzroy River (Western Australia) were most tolerant of high pH. The performance of these provenances in this experiment generally accorded well with that in saline field environments.     

Lignification and peroxidase in tension wood ofEucalyptus viminalis seedlings

Seedlings ofEucalyptus viminalis were grown for 50 days with their stems bent so tension wood would form. Every 10 days the lignin content, monomeric composition, and peroxidase activity in the tension wood were compared with those in the lower side (opposite wood) and in vertically grown controls. The lignin content in the developing tension wood started to decrease after 10 days of bending and kept decreasing for 50 days, whereas those in control plants and opposite wood remained almost unchanged. The yields of syringaldehyde from tension wood by nitrobenzene oxidation increased, and consequently the syringyl/ guaiacyl ratio of the lignin was higher in tension wood than in opposite wood and control plants. The peroxidase ionically bound to the cell walls (IPO) catalyzed oxidation of guaiacol and syringaldazine. The syringaldazineoxidizing activity of IPO from tension wood increased, whereas the activities of IPO from opposite wood and control plants did not show any marked change. In tension wood the increase in syringaldazine-oxidizing activity of IPO was consistent with an increase in the syringaldehyde yield. This suggests that IPO contributes to syringyl lignin deposition as other enzymes involved in the monolignol biosynthesis do in tension wood formation.This study was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

Genetic parameters and expected gains from selection for monoterpene yields in Petford Eucalyptus camaldulensis

Genetic parameters were estimated for yield of 1,8-cineole and total monoterpenes as a fraction of leaf weight in nineteen open-pollinated families of Petford origin at 3.75 years in two progeny/provenance trials of E. camaldulensis in Zimbabwe. Both traits appear to be highly heritable and, as expected, were strongly genetically correlated, with narrow-sense individual heritabilities near 0.50. Expected gain in the first generation following individual selection in the trials of one tree in 10 for either trait is about 25–32%.Genetic correlations between growth traits and 1,8-cineole yield were small. This indicates that both traits might be improved concurrently thus enhancing the economics of growing Petford E. camaldulensis for wood and medicinal oil. However, the presence of moderate and unfavourable genetic correlations between growth traits and total yield of monoterpenes warrants further study. It was not possible to gauge the significance of apparent family × site interaction for 1,8-cineole yield in this study. However, a test of rank correlation showed an association (Ip<0.01) between family rankings on each site and the highest-yielding trees on both sites came from the same families. This raises the possibility of being able to select individuals for cloning that yield well over a range of site conditions.     

Induced competition among scots pine seedlings and its effect on future timber quality

Height and diameter increment and timber quality in Scots pine (Pinus sylvestris L.) planted as seedlings of different sizes were studied in two experiments. When compared 32–37 years after planting, seedlings that were smaller than neighbouring seedlings at the time of planting, had generally attained lower height and diameter, and had higher mortality compared to seedlings that were of equal size or larger than their neighbours. Tree size was strongly related to seedling size two years after planting. Trees originating from small seedlings had thinner annual rings and branches than trees originating from large seedlings. These characters are of importance for timber quality. It seems that the competitive ability of a tree is to a large extent established early in stand development.     

Pasture floristic composition in different Eucalyptus species plantations in some parts of northern Guinea savanna zone of Nigeria

In view of the recurrent drought and human population pressures which have drastically reduced the density of pasture species within the Nigerian savannas, the nomadic herdsmen rely mostly on silvipastoralism, grazing their herds in Eucalyptus plantations. In this study, the population of understorey forage and non-forage speicies and the relative light intensities on the forest floors of two Eucalyptus species, viz: E. citridodora, and E. camaldlensis were compared with those of open savanna lands at Kabama, Samaru and Guga, all within the Northern Guinea savanna zone.At normal 3 m by 3 m spacing between trees, the herbages were fewer in the plantations and the E. citridora plantation had only about half the number of species observed under E. camaldlensis in the same and other sites despite similarities in light intensity levels in all the plantations. This information forms a guideline in using eucalyptus silvo-pastoral farms.     

Performance and yield of 14 eucalypt species on Imperata cylindrica (L.) Beauv. grassland 3 years after planting

A species trial with 14 eucalypt species with randomized complete blocks design was planted on Imperata cylindrica dominated grassland in South Kalimantan, Indonesia in January 1987. The site was prepared mechanically. No fertilizers were used. At the age of three years E. camaldulensis had clearly the highest survival rate (95%) and mean annual increment (5.9 m³ha^–1a^–1) compared with the other species tried. It was followed by E. urophylla, E. deglupta, E. pellita, E. tereticornis, E. alba, E. torelliana, E. intermedia, E. grandis and E. pilularis. Four other species, E. phaeotricha, E. resinifera, E. cloeziana and E. microcorys died either in the nursery or immediately after planting. All the eucalypts tried had narrow crowns and open canopies. It is suggested that eucalypts are not recommendable for grassland reforestation under minimum plantation tending. Effects of intensive weeding, spacing, fertilizing and performance in second rotation or mixed stands should be tested to elaborate the suitability of eucalypts on grasslands.     

Site preparation of abandoned fields and early establishment of planted small-sized seedlings of silver birch

Field experiments at two sites in Sweden investigated the possibility of establishing silver birch (Betula pendula Roth) on abandoned fields by planting small (5–10 cm tall) seedlings. The effects of five modes of soil preparation (no preparation, rotary cultivation, deep ploughing, soil inversion, and removal of topsoil) with or without preliminary herbicide weed control on seedling performance were studied for three growing seasons following plantation. Both a split-plot design and a randomized block design were used to evaluate the experiments. Where there was no site preparation, seedling survival was close to nil. The highest seedling survival rates on the site with sandy soil were obtained on sites prepared by removing topsoil, or by transposing it by deep ploughing. On the site with silty soil, the best survival was observed on sites created by soil inversion or rotary cultivation. The tallest seedlings were found on sites with topsoil retained within the soil profile. Herbicide application with glyphosate promoted seedling survival and seedling height in combination with no soil preparation, but was of little effect when followed by mechanical soil preparation.     

Rapid predictions of cold tolerance in Douglas-fir seedlings using chlorophyll fluorescence after freezing

Chlorophyll fluorescence measurements were performed on the foliage of 3-year-old (11/2+11/2) nursery-grown Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings after exposure to controlled freezing temperatures, in the laboratory, to assess low temperature tolerance. The seedlings were propagated in an Irish nursery and lifted at monthly intervals overwinter 1999 and 1999–2000. Excised shoots from first-order laterals were frozen, in the dark. After freezing, needles were immediately assessed using chlorophyll fluorescence. The excised shoots were then maintained under controlled conditions for 14 days and visually assessed for needle damage. The chlorophyll fluorescence parameter, F _v/F _m, accurately predicted cold hardiness and was linearly related to visual needle damage and short-term survival. An equation was constructed using F _v/F _m data for determining the LT₅₀, that is, the freeze temperature causing 50% seedling damage. The predictions of F.LT₅₀ (fluorescence-based empirical determination of LT₅₀) have been tested over two seasons (i.e., against a second independent data set) with variability between 0 and 1.8°C of visual estimates, though predictions were often 1.1°C of the visual assessment. This approach provided a simple, rapid and accurate prediction of cold tolerance, under climatic conditions where in situ measurements are unreliable. The method can be used to predict if Douglas-fir seedlings have developed sufficient tolerance for lifting to the cold-store, or for planting.     

不同桉树在昆明市海口林场的早期生长研究

对昆明市海口林场2012年栽植的5种桉树早期生长性状进行了观测研究。结果发现,5种桉树中,造林成活率较高的有本沁桉、邓恩桉及多利桉,树高和地径表现最优的是多利按。不同种桉树中苗圃地生长表现最优的,上山栽植以后生长表现不一定最优,这与不同生长发育阶段、不同环境条件有着密切关系。     

Field survival of containerized red and jack pine seedlings inoculated with mycelial slurries of ectomycorrhizal fungi

Red pine and jack pine seedlings growing in styroblocks were inoculated 8 wk after sowing with mycelium/agar slurries of 3 mycorrhizal fungi (Laccaria bicolor, Scleroderma citrinum, and an unidentified basidiomycete), and one suspected mycorrhizal fungus (Cantharellula umbonata). Seedlings inoculated with L. bicolor developed mycorrhizae earlier and in greater numbers than the other inoculation treatments, with red pine out-performing jack pine in both respects. At 34 wk following sowing, seedlings were outplanted on a cleared xeric site in Baraga Co., in Michigan's Upper Peninsula. Seedlings inoculated with C. umbonata failed to form mycorrhizae and were not outplanted. Inoculation treatments did not affect shoot or root weight at outplanting. Red pine inoculated with L. bicolor averaged 21% and 19% greater survival compared with control seedlings after one and two years in the field, respectively. Other inoculation treatments failed to increase seedling survival for either tree species. Jack pine demonstrated higher overall survival than did red pine for both years in all corresponding inoculation treatments.     

Root growth and hydraulic conductivity of southern pine seedlings in response to soil temperature and water availability after planting

Comparison of the root system growth and water transport of southern pine species after planting in different root-zone environments is needed to guide decisions regarding when, and what species to plant. Evaluation of how seed source affects root system responses to soil conditions will allow seed sources to be matched to planting conditions. The root growth and hydraulic conductivity of three sources each of shortleaf, loblolly and longleaf pine seedlings were evaluated for 28 days in a seedling growth system that simulated the planting environment. Across species, an increase in root-zone temperature alleviated limitations to root growth caused by water stress. In the coldest temperature, longleaf pine maintained a higher hydraulic conductivity compared to shortleaf and loblolly pine. Without water limitation, the root growth and hydraulic conductivity of shortleaf and loblolly pine were superior to that of longleaf pine, but as water availability decreased, the root growth of longleaf pine surpassed that of loblolly pine. Hydraulic conductivities of the seed sources differed, and differences were attributed to either new root growth, or an increase in the efficiency of the root system to transport water.     

Tree Performance and Root-Zone Salt Accumulation in Three Dryland Australian Plantations

Doubts exist about the effectiveness of establishing trees near saline discharge areas on farmland to manage dryland salinity. These centre on low rates of water uptake from saline water tables, salt accumulation in tree root zones and the consequent poor growth and survival of trees. Despite this, trees still survive in many plantations established adjacent to saline discharge areas and land-holders often favour such locations, as they do not compete for arable land such as that occurs with plantings in recharge areas. Tree performance and salt accumulation were assessed in three experimental plantations established adjacent to saline discharge areas 20–25 years ago. These were all in the 400–600 mm rainfall zone of south-western Australia. Mean soil salinity, within 1 m of the surface, ranged from 220 to 630 mS m⁻¹, while permanent ground-waters occurred within 2–5 m of the surface and had electrical conductivities ranging from 175 to 4150 mS m⁻¹. The study confirmed the low growth rates expected for trees established over shallow, saline water tables in a relatively low rainfall environment, with estimated wood volumes in Eucalyptus cladocalyx, E. spathulata, E. sargentii, E. occidentalis and E. wandoo of between 0.5 and 1.5 m³ ha⁻¹ yr⁻¹. Values of up to 3 m³ ha⁻¹ yr⁻¹ were obtained on soils with low salinity (<200 mS m⁻¹). The excellent survival (>70%) of several Eucalyptus species confirms that discharge plantations species can persist, despite increasing soil salinity. However, the long-term sustainability of such plantings (50–100 years) without broader landscape treatment of the present hydrological imbalance must be questioned.