Hollows in jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) trees: II. Selecting trees to retain for hollow dependent fauna

From a sample of 665 hollows found in 154 jarrah (Eucalyptus marginata) and 85 marri (Corymbia calophylla), we identified 204 hollows in 84 trees that were potentially suited to one or more of 10 species of hollow using birds and mammals. Occurrence of these hollows increased with tree age, tree size, and species (marri bore more usable hollows than jarrah) and increased amounts of dead wood in tree crowns. Hollow occurrence was most likely in trees with moderately senescent crowns with damage to intermediate sized branches, and the largest hollows were more likely to occur in more highly senescent crowns. Evidence of termite invasion at the tree butt was not related to occurrence of hollows. For all but one of the birds and mammals we considered, dead trees were no more likely than live trees to contain hollows.

Our study indicates that for the purpose of forest management planning, 130 years can be taken as the typical minimum age for the formation of usable hollows in jarrah and marri. The current minimum prescribed diameter for “habitat trees” (trees retained in logged areas to supplement existing hollows), which corresponds to a mean age of 171 years, is thus a realistic minimum size for these retained trees. We recommend raising the prescribed range of crown senescence for retained habitat trees to increase the probability of providing large hollows suited to large species such as red-tailed black cockatoo, and common brushtail possum, and maternal hollows used by smaller species. Retaining the largest trees with appropriate crown attributes will substantially increase the probability that these trees will bear usable hollows.     

Photosynthetic response to green crown pruning in young plantation-grown Eucalyptus pilularis and E. cloeziana

The loss of foliage through pruning of live branches may reduce tree growth or it may be compensated by photosynthetic up-regulation of the remaining crown. Here, the changes in light-saturated photosynthesis following pruning to remove 50% of green crown length were examined in 4-year-old Eucalyptus pilularis Sm. and Eucalyptus cloeziana F. Muell. trees. The objectives of the study were to: (1) compare leaf-level physiological (light-saturated photosynthesis (A_max), stomatal conductance (g), transpiration (T), dark respiration (R_d), quantum yield (Φ), light compensation point (Γ), water-use efficiency (WUE), nitrogen-use efficiency (NUE)) traits in species with contrasting crown dynamics and structure, (2) examine the effect of crown position on these traits, and (3) examine the effect of pruning on A_max, g, T, WUE, NUE, leaf N and P concentrations and specific leaf area (SLA). Prior to pruning there were no differences in R_d, Γ and Φ between E. pilularis and E. cloeziana but differences in A_max, T, g, leaf N, leaf P, WUE, NUE and SLA. Whereas the rate of physiological processes (A_max, T, and g) and leaf N and P concentrations increased with crown height, R_d, Γ, Φ and SLA declined along this vertical gradient, except in the upper crown of E. cloeziana where A_max, T and g were not different to the lower crown. No up-regulation of photosynthesis or changes in leaf physiology occurred between 6 and 13 months after pruning in either species. The results provide an important basis for modelling pruning effects in process-based tree growth models.     

Water table decline alters growth and survival of Salix gooddingii and Tamarix chinensis seedlings

In the western United States, many native riparian forests are declining downstream from dams and diversions, primarily due to a lack of successful regeneration of native species. Conceptual models have been described that incorporate stream flow characteristics that promote successful regeneration of western riparian Populus seedlings. However, these models need to be calibrated for additional species and specific stream characteristics. In this study, we examined the growth and survival of two dominant Sonoran desert riparian tree species, a native Salix gooddingii, and an exotic, Tamarix chinensis, to simulated water table declines at rates of 0, 1, 2, and 4 cm/day. Salix seedlings performed best in the 0 cm/day treatment in which the soil was saturated and showed decreasing survival and growth with increasing rates of water table decline. Root-to-shoot ratios were high for Salix, but root elongation rates were low with an emphasis on lateral root development. This root growth pattern may be an adaptation to habitat where Salix typically grows, near the stream channel where the water table is shallow but the likelihood of flood scour is high. Lateral root development may help to protect Salix seedlings from late season flood scour. Tamarix seedlings showed consistently high survival across all treatments and had the greatest growth in the 0 and 1 cm/day treatments. Tamarix seedlings had greater root elongation rates in response to water table decline relative to the control, with the greatest elongation in the 1 cm/day treatment. Greater root elongation rates and higher drought tolerance allowed Tamarix seedlings to persist in dry soils where Salix seedlings died. Differences in growth and survival of these two species in response to water table decline will need to be incorporated into management practices to promote successful native riparian tree regeneration.     

Hollows in jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) trees: I. Hollow sizes, tree attributes and ages

One hundred and fifty-four jarrah (Eucalyptus marginata) and 85 marri (Corymbia calophylla) trees were measured and assessed, and the numbers and sizes of hollows in these trees were determined by destructive sampling; 665 hollows were located and measured. The relationship between tree diameter and tree age was determined from counts of annual growth rings on 162 of these trees. Large trees and trees with moderately senescent crowns individually bear the most hollows. Although the number of hollows found in individual trees increased with tree diameter, the distribution of tree diameters in the forest is skewed and the large number of small trees with diameters between 40 and 80 cm contribute approximately 50% of all hollows in the jarrah forest. The distributions of entry size, and of hollow depth, are highly skewed, with small hollows occurring more frequently than large hollows. Although jarrah trees bear more hollows than marri trees and the distribution of entry sizes is similar for both tree species, the hollows in jarrah are significantly smaller than the hollows in marri. Most hollows are cylindrical in shape, vertically oriented and occur in dead wood in the tree crown. Relatively few hollows (14%) occur in the tree bole or at crown break. Counts of hollows made from ground level are inaccurate as estimates of the actual number of hollows in trees.     

Growth and survival of termite-piped Eucalyptus tetrodonta and E. miniata in northern Australia: Implications for harvest of trees for didgeridoos

The most common canopy trees in the savannas of northern Australia, Eucalyptus tetrodonta and E. miniata are also two of the most common species harvested to make didgeridoos, the traditional musical instrument of northern Australian Aboriginal peoples now experiencing high demand from international markets. Most of the trees of the area naturally have hollow cores, or pipes, due to termite activity, but little is known of the relationships of the cores to size of tree, tree growth or survival. In a wooded savanna of northern Australia, 267 individual trees with known growth and survival rates were cored to determine degree of termite-piping. Generalized linear modelling and multi-model inference showed that frequency of piping increased with diameter (dbh) tree for E. tetrodonta, but >85% of E. miniata trees were piped regardless of dbh. Growth (dbh increment) and survival (4-year) were size-dependent. Survival of both species decreased strongly with degree of piping (pipe ratio). For any given diameter, the growth rate of E. miniata trees was independent of pipe ratio, but for E. tetrodonta trees decreased strongly with pipe ratio. From modelled data, a 10-cm tree with pipe ratio of 0.60 was very vulnerable, growing at 0.0 cm year⁻¹ with 46% survival rate, whereas a 40-cm tree, even with large pipe ratios (0.80), grew 0.05 cm year⁻¹ with 98% survival rate. Traditional methods of tree harvesting remove only those smaller hollow trees that are already suffering low growth rates and are likely to die before reaching maturity, whereas current large-scale commercial methods also remove trees with higher growth and survival rates—those trees most likely to contribute to sustainable tree populations. Incorporating traditional selection and harvest methods into current commercial operations would help ensure longevity of this source of livelihood for indigenous peoples of the region.     

Incidence and new records of Mycosphaerella species within a Eucalyptus globulus plantation in Western Australia

Eucalyptus globulus is the predominant exotic hardwood plantation species in Western Australian (WA), and is often planted adjacent to native eucalypt forests. The increase in number of Mycosphaerella species associated with Mycosphaerella leaf disease (MLD) in E. globulus plantations in WA in the past decade has raised concern about the possible movement of pathogens between the native forests and plantations. In order to determine whether the introduction of new E. globulus genetics into WA may have further exacerbated this situation, juvenile and adult foliage were taken from a genetics trial near Albany, WA consisting of 60 full-sib families and Mycosphaerella species identified using morphological and molecular tools. Eleven species of Mycosphaerella were identified from one plantation: Mycosphaerella fori (Pseudocercospora fori) and Mycosphaerella ellipsoidea are new records for Australia; Mycosphaerella tasmaniensis (Passalora tasmaniensis) and Mycosphaerella suttoniae (Kirramyces epicoccoides) are new records for WA; and Mycosphaerella nubilosa, Mycosphaerella cryptica, Mycosphaerella marksii, Mycosphaerella molleriana, Mycosphaerella lateralis, Mycosphaerella aurantia and Mycosphaerella parva, previously recorded for WA. The most frequently isolated species from juvenile foliage was M. marksii (77%) followed by M. nubilosa (33%). M. nubilosa was most frequently isolated from adult leaves (88%) followed by M. parva (7.5%). Three species, M. molleriana, M. lateralis and M. cryptica, were only isolated from adult leaves while M. ellipsoidea was only isolated from juvenile leaves. These records increase the number of known Mycosphaerella species from eucalypts in WA from 10 to 13. The increase in the number, distribution and impact of Mycosphaerella species contributing to MLD in WA is of concern both to the potential productivity of the plantations and the biosecurity of native WA Eucalyptus species. Continued monitoring of the plantation estate is required to understand the dynamics of the host–pathogen interactions.     

Impact of artificial pruning on growth and secondary shoot development of wild cherry (Prunus avium L.)

Producing high value veneer wood requires that the tree bole be branch-free. This can be accomplished by natural or artificial pruning. Since wild cherry does not self prune well, pruning artificially is the only practical option. The study analysed the effect of conventional whorl-wise pruning and selective pruning, on height growth, diameter growth and secondary shoot development of wild cherry. Four pruning treatments were applied on cherry trees in summer 2007, one group of cherries was left unpruned to serve as a control: treatment C1 (upper 5 whorls left), C2 (upper 3 whorls left), S1 (removal of branches larger than 3 cm or with an angle to the stem < 40°), S2 (removal of branches larger than 2 cm or with an angle to the stem < 40°), N (unpruned). Data showed that height growth was not affected by pruning. In contrast, diameter growth at breast height of the C2 pruned cherry was reduced by approximately 5% (SE = 2.7%) in the year of pruning (trees were pruned in July). This pruning treatment produced significant (p = 0.028) nine percent less diameter growth than the control in the second year following pruning. The diameter increment of the C1 pruned trees with five whorls left after pruning and the selective pruned cherries were only about 4% (SE = 4.0%) smaller than the control after two years. This loss was statistically not significant. Analyses showed that on selective pruned trees the survival rate of secondary shoots was significantly reduced compared to those on whorl-wise pruned trees. Significant differences in the size of the secondary shoots were only found between the C1 and S1 (p < 0.05) pruned trees. We did not find differences in the total number of secondary shoots per tree among pruning treatments. Solely from a tree growth perspective, the moderate whorl-wise pruning treatment C1 and the selective prunings were equally effective in minimizing the reduction of diameter growth and are recommended in practice. However it was found that the survival of secondary shoots was reduced on selective pruned trees although the amount of pruning work needed in selective pruning was slightly greater than conventional moderate pruning.     

Fertilizer/site interactions on the growth and foliar nutrient levels of Eucalyptus grandis

This paper examines some of the relationships between site, fertilizer type and foliar nutrient levels with regard to growth responses of Eucalyptus grandis (Hill ex Maid.) in order to optimise fertilizer recommendations and characterize their effect on tree growth. Six comprehensive fertilizer trials, employing confounded factorial designs, were laid out over a number of years on six sites in Natal and Zululand, covering a wide range of environmental conditions. Experiments were assessed and compared at 4 years of age in order to control within-block variation of site factors. The major growth responses were to N and/or P, N only being suitable on sandy soils low in organic matter. Topsoils very high in mineralizable N responded to applications of P only. Sites with moderate amounts of organic matter required both N and P. Potassium generally had a depressive effect. Foliar values agreed well with responses to fertilizers, and were useful in characterizing sites and determining optimum application levels. The improvement in yield as a result of fertilization was relatively greatest on poor sites. However, there was a trend for the response in absolute terms to increase with site quality. For fertilizer recommendations to be optimized, there is a need for sites to be classified in terms of their soil water availability and the organic-matter content and texture of the topsoil. As improvements in growth increase with time, they are probably due to changes in root development and structure, rather than overall nutrient status. Thus, fertilizing must be viewed only as an integrated part of establishment practices, including the condition of nursery stock, site preparation and weeding.     

Nutrient store and export rates of Eucalyptus urograndis plantations in eastern Amazonia (Jari)

Nutrient loss due to export of wood and bark of 4.5-year-old Eucalyptus urograndis was studied in the Jari project, eastern Amazonia, Brazil. Results are based on estimates of biomass, above-ground nutrient store, and nutrient stores in the soil. Thirteen stands varying in site conditions and the number of previous rotations (up to three), were studied. Average nutrient losses due to export of wood and bark, as a percentage of the element store in the above-ground tree biomass, were: N, 65%, P, 54%; Ca, 76%; K, 57%; Mg, 61%. A comparison of export losses with the present soil stores of Ca, K and Mg cations shows that export is equal to or surpasses the remaining soil store to a depth of 100 cm. As a result of the last narvest, about 200–250 kg Ca and about 100 kg K ha⁻¹ were removed. In spite of uncertainties about other unknown inputs and outputs, one has to conclude that the next rotation may be endangered by acute deficiency of mineral nutrients, especially of Ca.     

Deposition of atmospheric constituents and its impact on nutrient budgets of oak forests (Quercus petraea and Quercus robur) in Lower Austria

Geochemical processes in central European oak ecosystems (Quercus petraea and Quercus robur) suffering stand decline were studied in two oak stands of the Weinviertel, Lower Austria, about 30 km north of Vienna. Stores of chemical elements were determined by soil and biomass inventories. Deposition input was monitored over a 2 year period by bulk sampling of throughfall. Soil solution chemistry was studied by tension lysimetry over a 1 year period. Mineral nutrition of oak was judged by foliar analysis. Bulk deposition rates were 10–12 kg N ha⁻¹ year⁻¹, and 15–20 kg S ha⁻¹ year⁻¹. Total annual nitrogen gain is high. Both systems lose calcium and magnesium. Foliar nutrient levels indicate sufficient nutrition with main mineral nutrients, except for magnesium, which is in moderately low supply. Based on these findings, the hypothesis that pollutant deposition has been the cause of a sudden and severe appearance of decline symptoms in the second half of the 1980s must be dismissed. The data on deposition rates and ecosystem nutrient status, however, indicate that the soil of both systems is acidifying, nitrogen stores are increasing, and magnesium pools are depleted. If deposition of pollutants continues at current rates, a slow but steady degradation of many oak ecosystems in the Austrian Weinviertel is inevitable.     

Susceptibility of Eucalyptus globulus ssp. globulus to sawfly (Perga affinis ssp. insularis) attack and its potential impact on plantation productivity

Sawflies (Perga species) are leaf-damaging pests of the major plantation tree species Eucalyptus globulus ssp. globulus. This work describes the patterns of quantitative genetic variation in susceptibility to attack by Perga affinis ssp. insularis, based on data from a large open-pollinated trial containing genetic material from throughout the geographic range of E. globulus ssp. globulus. Forty three per cent of the trees in the trial exhibited damage from sawflies in either their sixth or seventh growth seasons. The incidence of damage was genetically based, with significant variation between geographic races of E. globulus ssp. globulus and highly heritable (h²=0.43±0.05) variation in damage incidence within races. Susceptibility to sawfly damage significantly affects plant fitness with both genetic and environmental correlations demonstrating that sawfly damage causes slow growth and increased mortality of trees. Mild and severe sawfly damage resulted in 16 and 31% reduction in the basal area of surviving trees, and the effect was consistent across races and families. Based on this data, we propose a model predicting relative plantation productivity of races of different susceptibility under different infestation regimes.     

混合接种Glomus与Pisolithus菌株对尾叶桉矿质营养吸收的影响

对混合接种ＶＡ菌根真菌苏格兰球菌霉和ＥＣＭ真菌彩色豆马勃影响尾叶桉苗期矿质营养元素吸收情况进行了研究。接种苗根真菌对苗木吸收Ｎ、Ｐ、Ｋ和Ｂ产季了较大的影响,主要体现在促进苗木对上述营养元素的吸收和积累。     

细叶桉种源—家系选择*

对细叶桉３个种源５０个自由授粉家系的生长性状和形质性状进行种源间和家系间差异分析和家系遗传变异及相关分析，结果表明细叶桉主要性状种源间和家系间差异都极显著，种源间的差异大于家系间的差异，来自澳大利亚昆士兰州的Ｌａｕｒａ种源优于其它种源。细叶桉家系生长性状和形质性状呈中度至强度遗传；枝下高、干形和冠幅与生长性状遗传相关极显著。运用指数选择法对５０个家系进行多性状综合选择，初步选出５个优良家系，可望获得２２．２３％的综合遗传增益。     

Capacity of stem water conductivity for two eucalyptus ( Eucalyptus urophylla ) plantations in South China

The sap flux density (SFD) was used as a measure of water capacity through stems of eucalyptus in this paper. It was found that daily SFD increased with daily vapor pressure deficit (VPD) in nonlinear regression Y=AX ³+BX ²+CX+D (R ²=0.702 1, n=135, p=0.01) at both sites (Hetou and Jijia) in the Leizhou Peninsula, Guangdong Province, China, where Y was daily SFD, X was mean daily VPD, A, B, C, D were constants. But extremely high VPD might limit stem water conductivity. The environmental factors, such as air vapor pressure deficit (VPD), solar radiation (RAD), etc., were the main determinants of SFD for E. urophylla plantations. The upper threshold of diurnal SFD was 51.55–55.65 mL·cm⁻²·h⁻¹ under the selected extremely high environmental conditions.     

Major constraints on shisham (Dalbergia sissoo) plantations and pathological debate on dieback disease in Punjab,Pakistan

Today,shisham plantations in Punjab,Pakistan face major constraints,especially dieback disease.This article reviews the multidisciplinary team work by forest and plant pathologists and economists to resolve the confusions in the pathology of dieback disease.It is intended to be of practical use to the foresters and plant pathologists reporting on this issue.     

Stand and individual tree characteristics associated with Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae) infestations within the Ozark and Ouachita National Forests

Many oak decline events have been reported within the past century in the eastern U.S., and important causal factors often differ among them. Coincident with a recent decline event in upland oak-dominant forests of Arkansas, Missouri, and Oklahoma was an unexpected outbreak of a native cerambycid beetle, Enaphalodes rufulus (Haldeman), the red oak borer. A large range in estimates of oak mortality throughout affected forests was presumably due to variation in species composition, where oak-dominant areas experienced the greatest mortality. We chose eight sites across the Ozark and Ouachita National Forests of Arkansas, similar both topographically and by oak dominance, to determine if other stand or tree characteristics were important factors in variation of E. rufulus infestations across these forests. At each site, we sampled ∼125 dead, declining or healthy host Quercus rubra L., northern red oak. We created an estimate of the E. rufulus population level at each site during the recent outbreak using counts of dated larval gallery scars within a subset (n = 120) of all Q. rubra sampled (n = 976). We used classification tree partitioning to determine host tree characteristics that differed among dead, declining, and healthy Q. rubra. We also used classification tree partitioning, followed by logistic regression to determine stand characteristics that varied significantly among high, moderate and low infestation stands as well as between forests. Models indicated that trees which died were smallest, grew the least during the borer outbreak, and were apparently suppressed. These dying trees were likely poor competitors for resources, allowing neighboring survivors to experience a growth release during the E. rufulus outbreak. Larval survivorship was higher in trees which died, though larval densities were not greatest within these trees, which suggests that resistance in these individuals was compromised. At the stand level, differences between forests were apparently more important than those due to borer infestation. E. rufulus populations were higher at sites with lower Q. rubra basal area. This reduced basal area was likely a result of greater Q. rubra mortality at these sites during the borer outbreak in the early 2000s.     

施肥对蓝桉幼林生长的影响

经５ａ研究结果表明,在省保山市石灰岩红壤区施肥能明显促进蓝桉幼林生长,肥效在１．５ａ时最大,９个施肥处理的树高、胸径平均增长３３．６９％、４８．３９％,造林后５ａ时,生长反应已经呈下降趋势,９个施肥处理的树高、胸径平均增长１６．４５％、１０．７１％。Ｐ 促进蓝桉增产的主要因素,每株施４３０ｇ钙镁磷肥的几个处理产好,Ｎ、Ｋ肥增产效果不明显,有机肥对蓝桉生长有促进作用。在９个施肥处理中,处理６（钙镁磷     

澳大利亚ECM菌在尾叶桉上的筛选及其接种效应

报道４３种澳大利亚及２种国产外生菌根菌株在广东尾叶桉人工林上的筛选试验的初期研究结果。分别对试验林６、１２和２４个月的生长情况进行了调查,数据分析结果表明,与未接种对照林木相比,接种试验林在树高和地径（或胸径）生长量上均表现出显著的接种优势（Ｐ〈０．０１）;接种林３次调查平均树高生长量最大增幅分别为２６．１％、３３．７％和２７．４％,地径（或胸径）最大增幅分别为１９．２％、２１．５９％和１９．３２％;２４个月时每公顷材积最大幅为５６．８％。Ｅ０７１０（Ｌａｃｃａｒｉａ）、Ｈ４６７０（Ｌａｂｙｒｉｎｔｈｏｍｙｃｅｓ）、Ｅ４５０１（Ａｍａｎｉｔａ）、Ｅ２０１３（Ｌａｃｃａｒｉａ）、Ｃ９３０１（Ｐｉｓｏｌｉｔｈｕｓ）、Ｈ１２７２（Ｓｃｌｅｒｏｄｅｒｍａ）、Ｈ１１９４（Ｔｈａｘｔｅｒｏｇａｓｔｅｒ）、Ｈ０６０３（Ｓｃｌ     

Provenance and family variation in growth performance of Eucalyptus tereticornis (Sm.) in a provenance cum progeny trial in Midnapore, India

Eucalyptus tereticornis Sm. is an important species for agroforestry and commercial plantations in India. Results of a combined provenance–progeny trial of E. tereticornis laid out in 2002 at Midnapore (West Bengal) located in eastern tropical region of India are reported and discussed. Twelve provenances representing 70 families from Australia and Papua New Guinea were evaluated up to the age of 3 years. As a local seed source open-pollinated seed collected from a land race, i.e., Mysore gum (commonly known as Eucalyptus hybrid) was used to serve as check material (control). Significant variation in plant height, clean stem height, girth at breast height (GBH) and field survival was observed due to provenances, as well as families within provenances. This offers an ample scope to a breeder for increasing the growth and productivity in E. tereticornis through selection of provenances and families having potential for higher productivity. Heritability (narrow sense) values were appreciable for growth traits. Within provenance individual tree heritability estimates for height, clean stem length, GBH and number of branches at age 3 years were 0.318, 0.215, 0.269 and 0.231, respectively (assuming a coefficient of relationship of 0.4 for open-pollinated families of E. tereticornis). Provenance of Walsh River, Queensland Australia performed best for plant height, clean stem height, GBH, number of branches and field survival. Apart from this, the provenance from Oro bay to Emo, Papua New Guinea and Burdekin river, Queensland also showed good performance. Provenance from Yurammie, SF from New South Wales performed poorest for growth and survival. Correlations on growth traits were high and statistically significant, indicating that substantial gains could be achieved through indirect selection for one trait based on the direct selection for another. Age–age genetic correlations between age 1 and 3 years for the growth traits were highly significant and positive. Geographic clinal variation pattern was observed as latitude was negatively correlated with height and GBH (P < 0.05); longitude with number of branches (negative, P < 0.05). Fair differences were observed between phenotypic and genotypic coefficient of variability.     

A comparison of two stand table projection methods for young Eucalyptus nitens (Maiden) plantations in Chile

The study compares two methods of stand table projection based on data from young Eucalyptus nitens (Maiden) plantations in Chile. The projected diameter distributions were estimated using the methods proposed by Nepal and Somers (1992) [For. Sci. 38 (1992) 120] and Cao and Baldwin (1999) [For. Sci. 45 (1999) 506]. The evaluation compared the observed and estimated diameter distributions for different projection intervals, using the Kolmogorov–Smirnov test and an error index called ‘relative discrepancy’. The evaluation showed that both methods are suitable for application in the Eucalypt plantations. However, the method proposed by Nepal and Somers proved to be more accurate, especially when the projection period extends over 4 years or more. Expected error and bias for the observed and estimated total and merchantable volumes at stand level were also evaluated. The observed error and bias were relatively low for both methods; however, some differences were detected when the volume distributions were analyzed at diameter class level.