Academic literature on the topic 'Eucalyptus regnans'

Thaumastocoris peregrinus is a serious pest of Eucalyptus species This invasive insect has established in Auckland New Zealand since it was first detected in March of 2012 Elsewhere in the world it causes enormous economic losses to the eucalypt forest industry but also damages urban trees in public spaces Laboratory experiments were undertaken to evaluate the suitability of four Eucalyptus host species for the development of T peregrinus where three of these species are economically important for the forestry industry and the other is a popular amenity tree The development of eggs nymphs and adults was evaluated and fecundity calculated in excised leaf assays in the laboratory As a result E nitens and E nicholii were identified as suitable host plants On the other hand the insect did not survive on either E fastigata or E regnans Accordingly this study contributes evidence that there may be lower risk to species within the subgenus Monocalyptus from T peregrinus As E regnans and E fastigata are two of valued eucalypt species grown for pulp in commercial forestry in New Zealand and worldwide these are positive findings for the forestry sector

A replacement series experiment was carried out to determine the competitive aggressiveness of three species, P. radiata, E. regnans and A. melanonylon towards each other at seedling stage. Seedlings of the three species were grown at an overall density of six plants per pot for each species combination, providing all combinations of two species from 0:6 to 6:O. In addition, seedlings were grown in pure stands from one plant to six plants per pot for the three species. The relative crowding coefficient, the relative yield total, the relative effects of intra- and inter-specific competition on the yield of each species were the four indices calculated. Acacia melanoxylon was the most aggressive species, followed by P. radiata then E. regnans. In comparison with their corresponding monoculture, A. melanonylon in mixtures showed the smallest decrease in shoot/root ratio, whilst P. radiata had a greater decrease and E. regnans showed the greatest reduction. The average relative yield total of E. regnans and A. melanoxylon was close to 1 for both shoots and roots, indicating an almost complete overlap in resource use between the two native species. The relative yield total of P. radiata and E. regnans was 1.27 for shoots and 1.48 for roots, suggesting a possible difference in resource use between them. The results of this experiment provide a valuable qualitative insight into the relative magnitudes of the effects of inter- and intra-specific competition between the seedlings of the three species.

This paper researched on Australian Eucalyptus regnans drying properties by 100°C Test Method, also researched 25mm-thick boards dried by air-kiln drying schedule. The result indicated that the species belongs to refractory wood when drying, with checks and collapse defects that develop easily. In order to improve the drying quality, we adopted the method of first air-drying the moisture content (MC) to four different ranges and then kiln-drying. The two phrase air-kiln drying schedule concluded that the drying cycle of 25mm-thick Eucalyptus regnans board from 76.34% to 13.11% MC was 33.5 days, and the drying quality of visible defect met the requirement for the first level of the Chinese national standards.

Seed production characteristics of Eucalyptus regnans following self (S), outcross (O), (S+O ) and open pollination were investigated as a contribution to understanding of breeding system control in this species. All five trees tested produced seed after self-pollination, although yield was reduced relative to outcrossing. Isozyme analysis was used to determine paternity of individual seeds produced by polli- nation with a 1 : 1 mixture of S and 0 pollens. Preferential outcrossing was demonstrated, with an average of 81% of seeds being outcrosses. S and 0 seeds were also found within the same open- pollinated capsules, confirming the experimental observation that receipt of outcross pollen does not per se preclude self-fertilisation. The independent probabilities of survival of S and 0 embryos, as determined from seed yield per 100 flowers after separate S and 0 pollination, accounted for much of the preferential outcrossing effect. However, some trees produced more outcrosses than expected and competitive interaction of embryo genotypes within a capsule cannot be discounted. Following open pollination, samples from 15 trees averaged 16.7 ovules and 1.48 full seeds per capsule, giving a mean seed : ovule ratio of 9.0%. The modal number of seeds per capsule was 1 and the maximum 9, while 21% of capsules yielded no full seeds. These observations and experiments suggest post-fertilisation control of the breeding system, dependent upon both embryo genotype and maternal resource allocation.

Node-derived shoot cultures of Eucalyptus regnans were established from in vitro grown seedlings on Murashige and Skoog basal medium supplemented with 0.5 mg L-1 (2 μm) zeatin and 0.05 mg L-1 (0.3 μm) napthaleneacetic acid. A double sterilisation method was essential to obtain clean material from seed. Microcuttings from established cultures were used to develop an efficient method for in vitro rooting. Rooting was best after a 7 day pulse on 20 mg L-1 (98 μm) indolebutyric acid. Hoagland's or Woody Plant Medium supported better rooting than MS basal medium and rooting was significantly enhanced by subculture to activated charcoal after the auxin pulse. Carbohydrate (sucrose or glucose) was essential for rooting while high light intensity was inhibitory. Optimal light conditions were a 12 h day (17 W m-2). In all, 90% of plantlets established in the nursery survived the winter.

The yield of Eucalyptus regnans logs for lumber production was evaluated. Crack width and length at each log end were measured. Two log-cutting plans were used to obtain sawn lumber. The first plan (PA) considered logs with diameters varying from 28 to 40 cm, and in the second plan (PB), the log diameters ranged from 42 to 56 cm (PB). Lumber yield was determined using two log volume methods: the Japanese Agricultural Standards (JAS) and Smalian’s equation. The deformations of E. regnans lumber were measured. The Australian and Chilean standards were used to classify sawn lumber. The results showed that logs had radial cracks at both log ends. Cracks were classified into two groups, considering the crack length. Regarding the lumber deformations, most boards exhibited level B bows and crooks in both cutting plans. Levels A and B twists were prevalent in PA, whereas in PB, level A significantly outnumbered level B. The lumber yield of E. regnans in PB was higher than in PA. The lumber yield determined by Smalian’s equation was higher than that determined by the JAS method. This research provides insight into the characterization of E. regnans for lumber production, highlighting its relevance in the forestry industry.

Se analiza la capacidad de retoñación de 5 especies del género Eucalyptus, E. delegatensis, E. globulus ssp. globulus, E. nitens, E. regnans y E. viminalis. Un año después de la corta sólo E. regnans no presentaba una retoñación suficiente como para asegurar la siguiente rotación de monte bajo. Las otras especies retoñaron bien, incluso E. nitens y E. delegatensis, especies que tradicionalmente se han considerado con ciertas limitaciones para rebrotar después de la corta.

Bryophytic communities in plateau forests of mature Eucalyptus regnans are distributed according to substrate type and microclimate, whereas those in gully rainforests are more catholic. Objective classification of releves indicated the extent to which groupings are shared between these major topographic sites and the degree to which their distribution is mediated by differences in microclimate. Communities on many substrates in E. regnans forests are either seral to a fern floor 'climax' or exhibit pattern and process cycles of regenerative stability.

Intermediates between E. regnans and E. macrorhyncha occur in E. macrorhyncha forests on the Cathedral Range sandstones up to 5 km from the nearest stands of E. regnans. Such intermediates are regarded as F1 hybrids, primarily because of their low variability. Except for one site adjacent to E. regnans, no introgression to E. macrorhyncha is found, suggesting that hybridization is a rare event. The presence of hybrids is likely to be a result of a 'third order reaction' requiring heavy synchronous flowering, attraction of suitable pollinators and the occurrence of bushfires within the retention time of capsules in the canopies. Intermediate trees exhibit water relation characteristics and essential oil contents similar to those of E. macrorhyncha but morphological features closer to those of E. regnans. Progeny of intermediates display wide variability, both morphologically and physiologically, between the putative parent species. Such rare, widely dispersed hybrid events may eventually lead to increased local variation of E. macrorhyncha and as such may have implications for evolution of eucalypt taxa in diverse habitats.

Insect visitors to the flowers of Eucalyptus regnans F.Muell. in a remnant natural stand were classified into 33 functional pollinator groups according to taxonomic affinity and body size. In total, 92% of insects caught were dipterans; however, most of these were small and did not contribute significantly to pollination. For the majority of taxa, which have short mouthparts and therefore need to intrude themselves into the flower while feeding on nectar, there was a highly significant relationship between body length and the number of E. regnans pollen grains carried on the body. Mean pollen loads ranged from 20 grains per insect for sepsid flies to 84 000 for large tachinid flies. An index of pollen-deposition potential, which is based on population size and pollen load, suggested that the larger tachinid, calliphorid and syrphid flies were the most important pollen vectors and that larger sphecid wasps also played a significant role. Many taxa appeared to contribute little to pollination because they were uncommon and/or did not carry large quantities of pollen. A convention is proposed whereby groups are weighted according to their contribution to total pollen-deposition potential. For E. regnans, a ratio of 5 Diptera/1 Hymenoptera + (Coleoptera/Lepidoptera) is described, with the taxa in parentheses contributing less than 10% of the total.

Steam reconditioning to recover collapse, in mid to low density eucalypt species, has been known for over ninety years. The current industrial practices for steam reconditioning have largely been based on a few older studies, which were often poorly documented and based on very small sample sizes. On top of this, many local practices and ‘rules of thumb’ have developed over time, many of which have a questionable scientific basis. This thesis was undertaken to more rigorously investigate and fundamentally understand collapse recovery, and try to optimise its application. The most obvious variable that kiln operators have control over is the moisture content of the timber prior to steam reconditioning. Experiments were undertaken to generate a range of moisture gradients (ranging from minimal to more industrially realistic) to evaluate the effect of moisture content on collapse recovery. An optimal moisture content for the core of the boards was found to be between about 18–20%, although there was no statistical difference in recoveries between about 17–25% moisture content. Below 15% moisture content recovery dropped off severely and intra-ring internal checking closure was incomplete, while at 25% moisture content an increased level of normal shrinkage, due to the early removal of drying stresses, was the main drawback. Above a core moisture content of about 35% incomplete closure of intra-ring internal checks was again observed. There was little evidence of re-collapse occurring in these high moisture content samples. Previously established relationships between density and collapse and drying rate were again generally observed in these experiments. However, for the first time an effect of collapse in reducing the fitted drying diffusion coefficients was also observed. It was also observed that, provided the moisture content of the board was in the critical range, most of the collapse recovery was achieved in the time it took to get the core of the board up to the steaming temperature of close to 100°C. This suggests that for most thicknesses a conservative reconditioning period of two hours at temperature is all that is required. This recommended shortening of the reconditioning cycle could dramatically increase the throughput of timber through the steam reconditioning chambers. Alternatively, it could mean that where modern final drying kilns are being used, the reconditioning treatment could be carried out within the final drying kiln. A finite element model was developed to demonstrate the mechanism by which collapse recovery occurs. The theory tested was that the elastic component that stores the energy to restore the shape of the deformed cell is primarily found in the S1 and S3 layers. In contrast, the inelastic component is primarily found in the S2 layer. The model generated here provided limited support for this theory.

Doctor of Philosophy
Steam reconditioning to recover collapse, in mid to low density eucalypt species, has been known for over ninety years. The current industrial practices for steam reconditioning have largely been based on a few older studies, which were often poorly documented and based on very small sample sizes. On top of this, many local practices and ‘rules of thumb’ have developed over time, many of which have a questionable scientific basis. This thesis was undertaken to more rigorously investigate and fundamentally understand collapse recovery, and try to optimise its application. The most obvious variable that kiln operators have control over is the moisture content of the timber prior to steam reconditioning. Experiments were undertaken to generate a range of moisture gradients (ranging from minimal to more industrially realistic) to evaluate the effect of moisture content on collapse recovery. An optimal moisture content for the core of the boards was found to be between about 18–20%, although there was no statistical difference in recoveries between about 17–25% moisture content. Below 15% moisture content recovery dropped off severely and intra-ring internal checking closure was incomplete, while at 25% moisture content an increased level of normal shrinkage, due to the early removal of drying stresses, was the main drawback. Above a core moisture content of about 35% incomplete closure of intra-ring internal checks was again observed. There was little evidence of re-collapse occurring in these high moisture content samples. Previously established relationships between density and collapse and drying rate were again generally observed in these experiments. However, for the first time an effect of collapse in reducing the fitted drying diffusion coefficients was also observed. It was also observed that, provided the moisture content of the board was in the critical range, most of the collapse recovery was achieved in the time it took to get the core of the board up to the steaming temperature of close to 100°C. This suggests that for most thicknesses a conservative reconditioning period of two hours at temperature is all that is required. This recommended shortening of the reconditioning cycle could dramatically increase the throughput of timber through the steam reconditioning chambers. Alternatively, it could mean that where modern final drying kilns are being used, the reconditioning treatment could be carried out within the final drying kiln. A finite element model was developed to demonstrate the mechanism by which collapse recovery occurs. The theory tested was that the elastic component that stores the energy to restore the shape of the deformed cell is primarily found in the S1 and S3 layers. In contrast, the inelastic component is primarily found in the S2 layer. The model generated here provided limited support for this theory.

Burning of logging slash resulted in apparent sterilisation of the soil surface to a depth of about 2cm and also increased soil surface pH, which in localised areas reached sufficiently high values to be toxic to seedlings. In vitro studies showed that high pH conditions caused seedling mortality in E. regnans although the lethal effect of a transient elevated pH was reduced at temperatures sufficiently low to delay germination. The pH above which detrimental effects were expected was in the range 8.4 to 9.0. Suppression of seedling growth was observed in field soil with glasshouse studies showing that this suppression was partly overcome by prior slash-burning or by addition of N and P fertilisers. Availability of soil moisture appeared to be the main factor limiting seedling establishment in the field. Slash-burning was associated with increased seedling emergence but also with increased mortality rates compared to an unbumt control. Although fungi were found to be associated with the majority of dying seedlings from the field, their involvement in seedling pathology was unclear. Most common among these isolates was a species of Phoma, representative isolates of which caused cliscolouration and stunting of E. regnans seedlings in vitro, but were not otherwise markedly pathogenic. Species of Alternaria and Cladosporium were also commonly found on seedlings and probably present as saprophytes. Pythiaceous fungi were isolated from seedlings but pathogenicity of these was not examined. Rhizoctonia solani (pectic zymogram groups ZG5, ZG7 and ZG10) were isolated from seedlings that had died in field soil under glasshouse conditions. Representatives of R. solani groups ZG5 and ZG7 were pathogenic to E. regnans in vitro• however Rhizoctonia was not commonly isolated from the field. Three bacterial rhizosphere isolates (two Pseudomonas fluorescens and Bacillus circulans) and a fungus (Epicoccum purpurascens) from E. regnans were evaluated as fungal antagonists. Three of these were shown to reduce mortality (due to R. solani ZG7) of seedlings in vitro following inoculation in the vicinity of seeds, with E. purpurascens providing 100% protection after 30 days (compared with 22% survival of controls). Surprisingly, B. circulans and E. purpurascens also increased seed germination rates. Of the antagonists, only E. purpurascens improved seedling establishment in a glasshouse trial, both in the presence and absence of R. solani ZG7. However neither treatment with E. purpurascens nor the fungicide Raxil (applied to seed in combination with Mancozeb) resulted in improvement in seedling establishment in a small field trial.

Theories developed within the paradigm of landscape ecology propose that biodiversity within any given patch will be influenced by the surrounding landscape context (LC). Here LC is defined as the vegetation or land covers surrounding the site. This thesis used empirical vascular plant abundance data from the Huon forest district in southern Tasmania to test the hypothesis that LC influences the floristic composition and successional trajectory of patches within Eucalyptus obliqua and E. regnans wet forest. Secondary objectives included measuring the spatial and temporal variation in LC of the study area and its association with timber harvesting; describing differences in the response to LC between species and plant groups; comparing the effect size of plant responses to LC with other environmental predictors; finding the spatial and temporal scale at which plants respond most strongly to LC; and determining whether the effect of LC varied in response to disturbance regime differences. Most studies in landscape ecology have explored the effects of fragmentation on native vegetation in an agricultural matrix. In contrast, forest patches sampled in this study comprised native forest of various ages and successional stages within intact to variegated landscapes (sensu McIntyre and Hobbs 1999) in a frontier region dedicated substantially to timber production. Variation in LC was investigated for the study region using a new metric: the Landscape Context Index (LCI). This metric provided a relative scale of vegetation maturity in areas surrounding any given 50 x 50 m pixel, measured in 500 m, 1 km and 2 km radii. LCI was mapped for three years (1947, 1985 and 2009). The average LCI score was lower in 1985 than 1947, and was lower again in 2009. The greatest declines in LCI score were associated with timber harvesting, although in settled areas conversion to plantations was also an important contributor to LC score decline. The extreme reductions in LCI score observed in the period between 1947 and 1985 were not observed in the second period, possibly due in part to the mitigating effect of the Forest Practices Code, which resulted in changes to timber harvesting practices, including increased dispersal and reduced size of clearfelled patches. Distance to the nearest mature forest edge (DMFE), was used as a surrogate for mature forest influence, a component of LC. Between 15 to 200 m DMFE, there was an observed gradient in assemblage variation, species richness and diversity in all three age classes of silvicultural regrowth forest studied (4–9, 22–28, and 41–45 years since regeneration). These trends were mainly driven by declines in richness and cover of mature forest affiliated species. Factors considered likely to contribute to differences in plant species response to LC are their sensitivity to micro-climatic variation (influenced by proximity to mature forest, and topography) and macroclimatic variation, their capacity to persist through disturbance, and their dispersal mode. Individual species abundance models for both mature forest affiliated species and pioneer species were stronger (e.g. 38 out of 56 common species using beta regression modelling) when they included both LC metrics and site environmental variables. Although LC was important in explaining variance in species abundance, it typically contributed less to model strength than other environmental predictors, such as soil, climate, topography and disturbance history. Abundance of most pioneer species was associated negatively with mature forest metrics, while the abundance of mature forest affiliated species was associated positively with these metrics. There was little evidence that plant species with bird or wind dispersed seed or that had seed able to persist through disturbance in the soil or in woody capsules were any less associated with LC metrics than species sensitive to disturbance with shorter dispersal capacity. It is therefore possible that such species were responding indirectly to LC through inter species competition, or because they were dependent on animal species sensitive to LC for their pollination or dispersal. LC effects on site micro-climate, soil and browsing pressure, which all vary with distance from edges of mature forest could also be influencing the distribution of species in ways that are associated with the distance from and proportion of mature forest in the landscape. Auto-correlation between LC metrics and site history are other factors that may be contributing to the observed responses of all plant species to LC metrics. There was only equivocal support for the hypothesis that floristic responses within regrowth forests are more strongly associated with the LC of the patch at the time that they were last disturbed rather than current LC. Interpretation of the response of vegetation to both the spatial and temporal scale of LC was hampered by the strong autocorrelation in LC scores between scales, and by the sampling methods chosen. The balance of evidence suggests that the LC in the years following disturbance and prior to canopy closure strongly influence the trajectory rate of succession, however colonization and extinction within sites may occur infrequently at any time so that later successional stages are still likely to be influenced by LC at all times. An interactive effect between proximity to mature forest and fire frequency was observed within secondary regrowth forests, such that patches burnt twice or more since 1898 exhibited greater assemblage differences with distance from the boundary compared with forest burnt only once. This was evidence that the response to LC is partly dependent on disturbance regimes at the site and that succession towards mature forest occurs more slowly in frequently disturbed patches. There was also a poor representation of the dominant rainforest trees and epiphytic ferns in regrowth forest that has colonized abandoned pastures (old fields), irrespective of the LC. Barriers to the colonization by rainforest tree species within old field regrowth may include the maintenance of more open canopy structure for longer periods than typical in uncleared regrowth forest disturbed by single fire events. An examination of all results in conjunction with those of other empirical studies suggest that successional trajectories in the species composition of wet eucalypt forests may be altered by changes in landscape configurations in response to silvicultural practices and changes in climate and associated fire regimes. Given the association between LC and succession in forest patches, the observed reductions in mean LCI scores across the study region may signal that recovery from the effects of wildfire, extreme climate events, and harvesting may be slower at the site level. If so, then current LC patterns reflect a reduction in resilience at the landscape scale. Predicted changes in climate and associated fire regimes may make local extinctions more likely in areas of low LCI score. In the context of landscape planning, although dispersal and pollination distances for most vascular plants is best measured in tens of metres rather than kilometres, landscape planning at 500 m to one kilometre may be sufficient to avoid local extinctions at finer scales and thereby prevent range contractions. Silvicultural methods and land management practices that may avert future losses in landscape resilience are discussed.

The effect of different stages of forestry practices on regeneration of Eucalyptus regnans and understorey and rainforest species was determined for logged coupes in South West Tasmania. Observations were made across six different logged sites which were mixed forests prior to logging. Results at different stages of logging activity were investigated with undisturbed mixed forests used as controls. Mudstone is the main rock type at the study sites, and on some sites was found to be combined with quartzite. Study sites were divided into two groups. The first group, unburnt sites, consisted of unlogged mixed forest sites, sites from which eucalypts had been selectively logged, and clearfelled sites. The second group consisted of sites which had been burnt. Sample quadrats on the burnt sites were classified according to fire intensity; unburnt (small patches within the generally burnt area), low medium and high fire intensities. Sites were classified as two, five, seven and nine years after burning. Regeneration of rainforest species occurred on logged sites, with regeneration on unburnt sites and on unburnt quadrats of burnt sites significantly greater than the regeneration of Eucalyptus regnans. Stocking rates of rainforest species was found to decrease with increasing fire intensity. A positive association occurs between the density of rainforest seedlings and mosses, and a negative association between density of rainforest seedlings and shrubs and ferns. Nothofagus cunninghamii and Eucryphia lucida regenerate better than other rainforest species. No significant difference was found between the regeneration rates of Nothofagus cunninghamii and Eucryphia lucida. Evidence was found which indicates that floristic composition changes with increasing time since fire and with different fire intensities. Eucalyptus regnans was found to regenerate poorly. On burnt sites, stocking rates of E. regnans increased with increasing fire intensity and this increase varied according to both fire intensity and time since fire. However, no strong evidence was found which indicated that greater stocking rates existed in quadrats on unburnt or burnt parts of the burnt sites. In contrast, when results were expressed in terms of mean seedling number, there was found to be a significant difference in the regeneration of Eucalyptus regnans in quadrats where fire had occurred compared to quadrats in unburnt parts of burnt sites with increasing time since fire. Furthermore, fire intensity did not affect regeneration rates and there was no obvious interaction between fire intensity and the time since fire. All species investigated were found to regenerate poorly on quartzite. Eucalyptus regnans stocking rates were not affected by fire intensity on quartzite sites. Phebalium squameum tended to be the most frequent tree seedling associated with Eucalyptus regnans on logged sites following fire. Acacia species were uncommon on the study sites. Photosynthetic responses to light and frost resistance of the main species were measured, in order to correlate field observations with the physiology of selected species. Based on photosynthetic responses to light, P hebalium squameum and Eucalyptus regnans are considered to be relatively light requiring (sun plants). The ferns Pteridium esculentum, Histiopteris incisa, Hypolepis muelleri and the hepatic Marchantia berteroana, dominate the ground layer of burnt sites during the early stages of recolonisation. The dominant shrubs on all sites, burnt and unburnt, included Anopterus glandulosus and Monotoca glauca. Mosses dominate the ground layer on all sites, at all the intervals since fire that were examined. The greatest number of species were found in sites where five years had elapsed since burning. Compared to undisturbed forest sites, sites two years after fire have a low index of similarity (approximately 50%). All other sites have indices of similarity which exceed 50%.

In the current competitive market for land in Tasmania, Australia, economic forest production may require large nutrient inputs to optimise productivity per unit area of land. Nitrogen (N) and phosphorus (P) fertilisers are often required at planting and in early stages of tree establishment to achieve rapid early growth and high survival rates. In Tasmania, further application ofN and P to plantations ranging in age from 2- to 20 years has also occurred. To effectively manage these plantations, a detailed understanding of nitrogen (N) fertiliser requirements and N retention in forests is required. Two field fertilisation experiments were used in this study, one in a 20-year-old Pinus radiata D.Don plantation growing in the north-east of Tasmania, on a Yellow Kurosol, and one in a 5-year-old Eucalyptus regnans F. Mueller plantation growing in the south, on a Brown Ferrosol. Both of these experiments were established in the early 1980s. Treatments at both sites included various combinations of P and N, applied as single-superphosphate and ammonium sulphate through a period of up to thirteen years. This study examines fertiliser-use, efficiency and impact on forest sustainability, including a detailed examination of the soil profile and litter at both sites. Nitrogen cycling was also examined, concentrating on the effect ofN fertilisation on N mineralisation in the contrasting surface soil horizons. After fifteen years of measurements, nitrogen fertilisation significantly increased volume growth at both sites. Two single applications of Palone (totalling 144 kg P ha\(^{-1}\)) doubled P. radiata stem volume from 78 m\(^3\) ha\(^{-1}\) (Nil) to 192 m\(^3\) ha\(^{-1}\) (P). Annual N fertilisation for a period of thirteen years (in addition to the P fertiliser) further increased P. radiata stem volume from 192 m\(^3\) ha\(^{-1}\) (P) to 344 m\(^3\) ha\(^{-1}\) ((P)Nl Y), at age 34 years. In contrast, applications of P alone (up to a total of 598 P ha1 ) had no effect on E. regnans growth, while annual N (plus P) fertilisation for thirteen years, doubled E. regnans growth from 125 to 281 m\(^3\) ha\(^{-1}\), at age 19 years. Although fertilisers may be used to increase forest growth there is concern that longterm N application may impact on forest sustainability through changes in the soil chemistry. At both sites in this study, significant changes occurred in the soil profile due to long-term fertilisation. Soil pH decreased due to both N and P fertilisation, at both sites. Significant reductions of0.7 and 0.3 of a pH unit were associated with the highest rates of fertilisation in topsoil (Al, 0-10 cm) and litter (02 horizon), respectively. Substantial reductions in exchangeable Mg concentrations were also measured, particularly in the Kurosol. In association with enhanced growth was a large increase in litter accumulated at both sites. Total litter masses (01 +02) ranged from 34.4 to 91.6 t ha\(^{-1}\) under P. radiata and from 21.6 to 102.4 t ha\(^{-1}\) under E. regnans. At both sites, the 02 horizon masses were significantly greater with annual fertilisation and were a substantial nutrient pool. Under P. radiata, 02 horizon mass was 40 t ha\(^{-1}\) when unfertilised and over 70 t ha\(^{-1}\) with fertilisation, while under E. regnans the mass was 14 t ha\(^{-1}\) when unfertilised and 77 t ha -l with fertilisation. This indicates that, in the cool temperate climate studied here, litter could be an important pool of nutrients. Long-term, annual applications of N fertiliser had no significant effect on the annual rate ofNNM measured in either the Kurosol or Ferrosol topsoil (0-10 cm). However, average rates in Kurosol topsoil were up to four-fold higher in the annually fertilised treatment. At both sites topsoil in situ net N mineralisation (NNM) rates measured at the end of the experiment were low, ranging between 13 and 52 kg N ha\(^{-1}\) yr\(^{-1}\). Such low rates of N mineralisation might have been associated with a prolonged period of low rainfall that occurred throughout the 18-month measurement period. To assess mineralisation independent of microclimatic effects that prevailed during the in situ study, rates of NNM were measured during aerobic laboratory incubations. In agreement with in situ studies, NNM in the Ferrosol topsoil was not changed by fertilisation. In contrast, the variation in rates ofNNM between treatments for the Kurosol topsoil was greater than that measured in situ, with fertilised topsoil mineralising ten times more N than that unfertilised. However, results were highly variable across moisture and temperature treatments. Despite the high amounts of N and P that had been applied during annual fertilisation, differences in total N and NNM in soil were small and highly variable. This result contrasted with the large differences in total N content and NNM rates in the 02 horizon from both sites. The influence of fertilisation on N cycling in litter produced clear results, i.e. daily rates of mineralisation (measured by aerobic laboratory incubations) were higher in annually fertilised than unfertilised litters, at both sites if incubations went for 7 days or longer. In contrast, low mineralisation rates in both topsoils often produced similar daily rates of NNM regardless of fertiliser treatments. In both topsoils, 60 days was required to produce a significant cumulative effect, resulting from a divergence in NNM rates between the fertiliser treatments during the later stage of the incubation. Increased replication of samples in laboratory experiments did increase the sensitivity of NNM measurements and significant differences between fertiliser treatments were measured. These results confirm the importance of litter as an N source in cool temperate plantations. The importance of the litter layer in N cycling was particularly evident under E. regnans, where N was most concentrated in the litter layer. In addition, the E. regnans 02 horizon accumulated significantly more P, S and Ca due to annual fertilisation. The effects of air-drying, incubation period, moisture content and temperature on NNM in laboratory studies were examined and found to depend on both the site and fertiliser treatment. This study indicated that higher NNM rates in topsoils would occur if soils were not maintained moist prior to and during incubations. This was particularly important for wetter sites, where canopy closure had occurred, resulting in smaller moisture fluctuations, as observed in the Ferrosol topsoil. Laboratory incubation conditions also influenced correlations between nutrient content (total N, P Sand Ca) and NNM. For example, NNM rates in the Kurosol topsoil were linearly correlated with N, P and Mg concentrations and pH when incubated at 20°C (p <0.05), but only with P at 10°C. This study indicated that minimum disruption of soil processes, particularly by drying was essential if accurate measurements of changes in soil N, in the cool temperate environment, were to be obtained. Hence, I could not identify a reliable indicator ofNNM for these plantations. In agreement with the in situ study, application ofN fertiliser seasonally (June, October, January or April) resulted in a short-term elevation of mineral N (less than six-months), particularly at the wetter Ferrosol site. April fertiliser application provided the longest period of enhancement and October the shortest, indicating that the current operational practice, of applying fertiliser in autumn (March-May), provides an adequate window for fertiliser uptake to occur. These trends also confirm that, independent of the time of fertiliser application, a six-month delay after fertiliser application was adequate to determine long-term fertiliser affects on NNM. This delay allowed mineral-N concentrations to attenuate to a low value that facilitated NNM measurements. In agreement with previous studies, at both sites rainfall appeared to be a strong regulator of mineral N availability after fertilisation. The importance of the litter was also highlighted, because it retained N fertiliser and thereby limited N leaching. In situ rates ofNNM and tree growth in the nil and annual fertilisation regimes in the P. radiata plantation were modelled using the process-based model CABALA. The model was developed with forest managers in mind as part of a silvicultural decision support system and links C, water and N flows through the atmosphere, tree and soil. In this study, CABALA was validated for P. radiata using parameterisation from published and unpublished data derived from an independent study. Predicted growth increases due to annual fertilisation within 15 % at age 34 years. Limitations to the current simulation were often due to the assumption that P was not limited at this site. Other responses to N movement in the forest system were also adequately predicted. However, this study indicated that functions for N mineralisation and canopy development need to be more sensitive to fertiliser inputs to adequately predict N availability in the mineral soil and litter layers. There currently seems to be an overdependence on C: N ratio, because it drives predictions ofN mineralisation in the CERES model, but there is doubt that this is an important controlling variable in forest systems. Further study of in situ NNM rates of litter horizons would be required to clarify the amount and mechanisms of N recycling that occur in these systems. Large growth rate increases from N fertilisation in both P. radiata and E. regnans plantations were often associated with significant changes in soil chemistry and litter accumulation. Substantial reductions in exchangeable Mg concentrations and soil pH indicate that careful site management is required. Significant accumulation of litter under these plantations may act a substantial future source of nutrients, including N availability for further tree growth, particularly when N mineralisation is low and not significantly effected by long-term fertilisation.

Eucalyptus regnans es el árbol latifoliado más grande del mundo, alcanzando más de 90 m. de altura. Se distribuye naturalmente en Victoria y Tasmania (Australia) y en Chile la especie es recomendada para gran parte de las regiones del Bío-Bío, la Araucanía y los Ríos. Es exigente, intolerante a sequías o heladas severas, desarrollándose mejor en suelos francos, profundos y con buen drenaje. En rodales naturales crece entre 15 y 20 m³/ha/año y en Chile entre 26 y 63 m³/ha/año. Se usa para madera aserrada, celulosa y papel, mueblería, ebanistería, chapas y otros.

Informe sobre la fabricación y evaluación del producto piso laminado de E. regnans, elaborando 3 tipologías de pisos laminados (lámina de E. regnans adherida a un tablero contrachapado de P. radiata; lámina de E. regnans adherida a un alma transversal de madera sólida y tulipa de P. radiata; lámina de E. regnans adherida a madera cepillada de P. radiata) y evaluando las propiedades físicas y mecánicas de los pisos laminados

El informe evalua alternativas de aplicación industrial para la madera de Eucalyptus regnans, con el objeto de fabricar a escala industrial un tablero OSB de 11,1 milímetros de espesor y determinar sus propiedades físicas y mecánicas. También se pretende comparar las propiedades de los tableros OSB fabricados con madera de Eucalyptus regnans y los requisitos establecidos por LP para los tableros que comercializa en Chile

Informe que contiene una evaluación de alternativas de aplicación industrial para la madera de Eucalyptus regnans, tendientes a fabricar a escala industrial un tablero de partículas de 18 milímetros de espesor, utilizando una mezcla de P. radiata y E. regnans, y determinar sus propiedades físicas y mecánicas. Luego, se comparan las propiedades del tablero de partícula fabricado con los requisitos establecidos por MASISA para los tableros que comercializa en Chile

La presente publicación contiene la metodología, resultados y conclusiones de un estudio cuyo objetivo es determinar los grados estructurales de 4 calidades visuales de la madera de eucalipto regnans que crece en Chile

Debido a la importancia de las plantaciones, se da énfasis a su investigación. Se establecieron una cantidad considerable de terrenos experimentales para introducción de especies y para estudio de crecimiento y manejo en plantaciones preexistentes y otras pruebas complementarias antes de iniciar finalmente programas de mejoramiento genético. Esto ha llevado al desarrollo de diferentes herramientas de manejo tales como: Índices de sitio y modelos de crecimiento simulado, manejo forestal y rendimiento de pino radiata, así como avances en la silvicultura del Eucalyptus, varios de los cuales se han adaptado a las condiciones de país. Durante las pruebas que se realizaron para la introducción de especies en diferentes partes del país se destacaron por su crecimiento el de Eucalyptus. El progreso que se ha logrado en la silvicultura del eucalipto ha hecho que durante los últimos años la tasa de forestación ha aumentado significativamente. Esto ha significado que además del Eucalyptus globulus que se ha utilizado tradicionalmente, se van añadiendo otras, como Eucalyptus niteng, Eucalyptus delegensis, Eucalyptus regnans, Eucalyptus viminalis y otros,que, además de su satisfactorio desarrollo, han supuesto la inclusión de nuevas áreas para producción debido a su mayor resistencia a climas fríos. En los últimos años también ha habido un aumento en la industria que procesa eucalipto, aumentando así la demanda de celulosa y madera aserrada

Abstract Eucalyptus regnans is the second tallest tree species in the world, only exceeded in height by the coast redwoods of California (Ashton 1975b). The natural forests are in Victoria and Tasmania in discontinuous areas between latitudes 37° and 43°S (Fig. 14.1). In Victoria it occurs at altitudes between 200 and 1100 m and is restricted to mountainous areas south of the Great Dividing Range in the eastern part of the state, but there is also an occurrence in the Otway Ranges south-west of Melbourne. In Tasmania it occurs between sea level and 700 m principally in the north-east, and in the south-east in the valleys of the Huon and Derwent Rivers (Griffin et al. 1982; Boland et al. 1984).

Abstract Eucalyptus viminalis (ribbon gum, or manna gum) is one of the most geographically widespread eucalypts in south-eastern Australia (Boland et al 1984), and occupies a very wide range of ecological conditions. On well-watered, fertile soils of gullies and hillsides it forms a tall forest, either alone or with other species including E. amygdalina, E. dives, E.fastigata, E. obliqua, E. radiata, and E. regnans. On drier, poorer sites on the plains and tablelands, on a variety of soil types, it occurs in low, open forests or woodlands, alone or with species such as E. amygdalina,E. dives, E. obliqua, E. paucifiora, and E. radiata. The geographic range is from southern Tasmania (latitude 43°S), through Victoria, southern South Australia, eastern New South Wales and the Australian Capital Territory, with high altitude stands extending to the Queensland border (29°S) (Fig. 17.1).