EUCALYPTUS GLOBULUS PROVENANCES

by

R.K. Orme
Forestry Commission
P.O. Box 207B
Hobart, Tasmania

INTRODUCTION

Nomenclature

E. globulus is the name normally associated with a fast growing eucalypt from Tasmania, commonly called “Tasmanian Blue Gum”, which has been widely planted overseas. Recent work by Kirkpatrick (1973, 75) suggests that the species E. globulus could be expanded to include the closely-related species E. maidenii F. M¨ell, E. bicostata Maid. et al. (E. st. johnii R.T. Bak), E. pseudoglobulus Naudin ex Maiden, as well as E. globulus Labill, since these species imperceptibly grade into one another through zones of contact. And he has proposed, but not yet formalised, the classification shown in Table 1. For the purposes of this paper the scheme of Pryor and Johnson (1971) will be used, except the name bicostata is used instead of st. johnii in the light of more recent work.

Table 1. Nomenclature and occurrence of E. globulus and closely-related species

Historical details

E. globulus Labill was first collected, and subsequently named by La Billardière, naturalist to the expedition of the French explorer Bruni d'Entrecasteaux which visited Tasmania in 1791 and 1792.

The species was first introduced to Europe about 1804 (Penfold & Willis, 1961) though it was through the efforts of Ramel, who returned from a visit to Australia in 1857, that plantations were established in southern Europe and North Africa. About this time eucalypts (mainly globulus) were introduced into Portugal, California, North America, Chile (1823), South Africa (1828), India (1843), the Argentine (1857), Egypt and Andalusia, Spain (1874) (Penfold and Willis, 1961).

An early reference to globulus in Europe is given by Balbino (1883) where he mentions that trees were first planted near Santander (Spain) in 1863. These seedlings came from the “Iles de Hyeres”, near Toulon, France. The parent trees of these seedlings probably originated from the collections made by La Billardière in Tasmania in 1792 since no seed would have been available at that time from other collections.

It is assumed that the original collections of globulus made by La Billardière came from the southern coastal area of Tasmania, since records of the voyage show that most time was spent by the expedition ships in the vicinity of Bruny Island, Tasmania (Triebel et al, 1958). The author has visited the “Iles de Hyeres” as well as many plantations of globulus in Spain and Portugal and has noted many affinities with provenances from south-eastern Tasmania.

There is a definite record of globulus seeds from Kelvedon, near Swansea, being sent to Palestine by a Mr. J.B. Cotton in 1882, but these apparently did not succeed (Karschon, 1963).

World importance of the species

E. globulus is now used in many countries and is, perhaps, the most widely distributed eucalypt species in the world. In Spain, Portugal and Chile it is by far the most important hardwood plantation species. However, it is also used commercially in many other countries including Rhodesia, the Congo, Kenya, Ethiopia, Morocco, Italy, Greece, India, Equador, Colombia, Bolivia, Peru, the Argentine, southern Brazil, and Uruguay. Estimates of the total area of globulus plantation in the world are difficult to obtain, but it probably is in excess of 400 000 hectares. ¹

The wood of globulus is mainly used for the production of paper pulp. Sometimes it is used for round timber and firewood, but this is only of local importance. In Tasmania its timber is used for heavy construction purposes such as piling, bridgeworks as well as boat building.

E. globulus is grown outside Australia as a short-term coppice crop with rotations from 8 to 12 years. Usually, it is cut and allowed to coppice three or four times before it has to be replanted due to loss of stools. In some countries, such as Spain and Portugal, the leaves may be harvested for the production of essential oils.

Despite its commercial importance as a plantation species, as well as the very limited nature of original collections, no large-scale provenance trials have ever been established.

Results of provenance trials

The Forestry Commission of Tasmania established a trial in 1973 at Branch's Creek in northern Tasmania to compare local and overseas provenances of globulus. Local provenances, especially one from King Island, have performed much better than overseas ones (Table 2). A similar result was reported by Pryor (1964) for trials with local and South African sources of E. grandis at Coff's Harbour, N.S.W. The greater genetic diversity of natural populations is a possible explanation for this.

Table 2. Recent results from Research Project No. 173 (Tasmanian Forestry Commission).

E. globulus provenance trial at Branch's Creek, Tasmania.

Variation in wood properties

CELBI (Celulose Billerud S.A.) has substantial holdings of globulus plantation in northern Portugal. Since 1964 this company has been working towards the improvement of wood quality by genetic selection within their plantations. As part of this programme some 260 plus trees were selected. Tests of the wood properties for these plus trees show that there is considerable variation between individual trees, which is the basis of their improvement programme. Some of their results are shown in Figure 1 (Anon, 1973).

Wood samples of three year old globulus from the Tasmanian trial were taken and have been tested by A.P.P.M. Ltd¹. These show that Tasmanian provenances tend to be easier to pulp in the presence of bark at this early age. But in the absence of bark no significant differences were found (Table 3). In all cases no differences were found in the paper-making properties of fibres from the various provenances, although there were large differences between chips with and without bark.

Fig. 1. Variability in some wood properties of 260 E. globulus plus trees (Anon, 1973)

Table 3. Results of pulping tests on wood samples from Branch's Creek Trial

Fig. 2. Natural distribution of E. globulus in Tasmania

MATERIALS AND METHODS¹

Preliminary

The project was initiated by the Forestry Commission of Tasmania as part of a joint research programme into eucalypt plantations with several local pulp and paper companies.

In our study we are mainly interested in E. globulus Labill, or Tasmanian Blue Gum, since this species is of the greatest value. Results from several species trials in Tasmania appear to show that globulus is a faster growing species than either maidenii or bicostata. In Victoria trials by A.P.M. Forests have given similar results (Anon, 1974).

Collection of Tasmanian Provenances

From local knowledge of the species it was decided to sample about twenty separate areas within the range of globulus in Tasmania (Figure 2).

We have collected from twenty provenances for Tasmania and the surrounding islands; nineteen of these are of globulus and one is pseudoglobulus (northern Flinders Island).

The eastern coast of Tasmania between Triabunna and St. Helens is relatively uniform with similar climate, land forms and geology; therefore we have only collected from three localities here. More samples have been taken elsewhere in Tasmania because of the greater differences between localities.

No details are yet available for the non-Tasmanian collections of the other species maidenii, bicostata and pseudoglobulus: it is thought that about ten localities in all will be sampled.

Parent trees were selected on the following basis:

1. Dominant trees or good co-dominants.

2. Straight form.

3. No sign of hybridization.

4. Well distributed within the sample area.

5. Good seed crop.

A 10 km × 10 km grid square has been used to represent each provenance chosen. Ten trees have normally been used to represent each provenance. However, in the case of a very small occurrence of globulus only five trees have been used. A separation of 80 m between parent trees has been maintained. The trees have been felled and measurements of diameter, taper, height and bark thickness taken. A wood sample, a botanical specimen, as well as the seed have been collected. Wood samples are presently being tested for their pulping properties in the laboratories of A.P.P.M. Ltd.

Collection of Non-Tasmanian Provenances

In addition to this study with globulus, collections of the related species, maidenii, pseudoglobulus and bicostata, are being made in collaboration by several other organizations: the Forests Commission of Victoria, A.P.M. Forests Pty. Ltd., and the Division of Forest Research, C.S.I.R.O. These collections will greatly enhance the value of our study since material of all species of “blue gum” will be available for testing. At this stage it is not known how many of these collections will be available, but it is hoped to obtain two or three provenances for each of the other species.

DATA ON TASMANIAN PROVENANCES

Natural occurrences of globulus

The species grows mainly in the south-eastern and eastern areas of Tasmania between sea level and 500 m. There are several very small occurrences on the western coast. It is also found on the islands of Bass Strait, at Wilson's Promontory and in the Otway ranges in Victora (Figure 3).

E. globulus grows together with other species of Eucalyptus and is seldom to be found growing alone in pure stands. It grows naturally on a number of different sites ranging from very wet (2 500 mm annual rainfall) in western Tasmania to quite dry (550 mm) in eastern Tasmania. The most common forest associations in which it grows are:-

1. Mixed Forest (southern Tasmania)

   E. regnans, E. obliqua and E. globulus growing over a canopy of the rainforest trees Atherosperma and Nothofagus.

2. Wet Sclerophyll Forest (southern and western Tasmania)

   Mixtures of E. regnans, E. obliqua and E. globulus with an understorey of shrub genera Pomaderris and Phebalium.

3. Dry Sclerophyll Forest (eastern Tasmania)

   1. E. obliqua, globulus and viminalis with a species of “peppermint” either tenuriamis, pulchella or amygdalina. This is the most common association of globulus.

   2. E. sieberi, E. globulus and E. viminalis form an association which is found at the northern end of the range of globulus, around St. Helens.

Normally globulus is a tree of between 30 m and 50 m in height, but specimens of 80 m are to be found growing on good quality sites.

The geology of eastern part of Tasmania is mainly composed of igneous rocks (Jurassic dolerite and Devonian granite) with smaller areas of Triassic and Permian sediments. The soils that globulus is found on are described as yellow podzolic or grey-brown podzolic soils. These are generally well leached, acidic, and most are considered to be of low fertility by world standards.

Variation within provenances

Data from the measurement of the parent trees collected have not yet been tabulated. However, to illustrate the range of ages, sizes and sites of the globulus provenances collected, some preliminary data are given in Table 4.

The small occurrences of globulus in western Tasmania are relict, probably arising from migration from Cape Otway, Victoria, via King Island by a former land bridge in the period of 10 000 to 15 000 B.P. The buds and fruits of these trees are significantly smaller than those collected from eastern Tasmania, but otherwise they closely resemble other collections.

Fig. 3. Distribution of E. globulus and closely related species

Based on map by Kirkpatrick (1975)

Table 4. Data for some Tasmanian provenances

Meteorological data

Data from four stations are given in Tables 5 and 6. These stations have been selected to represent the climate of eastern, south-eastern, western and inland Tasmania. The areas of globulus in Tasmania fall in Koeppen's Cfb climatic type: a warm temperate rainy climate.

Of interest is the fact that most globulus seed taken overseas was probably collected from coastal areas, yet there are much colder areas, with minimum temperatures down to -9°C, from which seed could be selected.

Table 5. Meteorological data for selected Tasmanian stations

Table 6 Average monthly rainfall (mm) for selected Tasmanian stations

Testing of wood properties

Wood samples have been obtained for parent trees for the Tasmanian provenances. This is the first time that a large-scale study of the variation in wood properties, between and within provenances, of any Eucalyptus species has been attempted.

It is expected that factors such as site, fire history, growth rate, and age of the samples will have a considerable effect on wood properties. However, the genetic component of wood properties is also very important.

The testing of these samples is being done at the Burnie mill of A.P.P.M. Ltd. under the direction of Mr. C. Turner. The following characters are to be tested:-

1. The degree of pulping under constant chemical and physical conditions (Kappa No.).

2. Yield of pulp under constant chemical and physical conditions (yield of celluloses).

3. Physical strength of paper made from test pulps.

4. Pulp colour.

5. Basic density.

Data from this testing will ultimately be published. It is also proposed to test wood samples coming from subsequent provenance trials from these collections. Such data will be very valuable for any subsequent tree improvement programme for this species.

OTHER DATA

Trials

In Tasmania it is planned to put in five large-scale provenance trials; most of these will be joint trials in collaboration between the Forestry Commission and the local pulp and paper industry and will be established about October 1977. Designs and locations have not yet been finalised. However, the Forestry Commission proposes to use a series of randomized blocks with three replicates per trial of a 100 tree plot for each provenance (i.e. one or two rows of 10 seedlings for each parent tree). It is hoped that other organizations will follow our example which will allow direct comparisons to be made between trials.

Enquiries for seed

Because of the international importance of these collections it has been decided to give seed in excess of Australian requirements to IUFRO for distribution. At this stage the amounts of seed available per provenance are not known. There is ample seed available for trials in the case of most of the Tasmanian globulus provenances. The collections from Victoria and N.S.W. are generally smaller and less seed will be available for distribution.

Figure 4. Open E. globulus forest at Jerico, Tasmania (500 m a.s.l.). Seed was collected from the large tree in the middle of the photograph, height 31 m, DBH 90 cm, age 70 years. (Photograph courtesy Forestry Commission of Tasmania).

REFERENCES

Figure 5. Falling tree for provenance collection on South Bruny Island. Height 48 m, DBH 151 cm, age 200 years. (Photograph courtesy Forestry Commission of Tasmania).

¹ A recent survey indicates that the area is now probably over 800 000 ha. Ed.

¹ Australian Pulp and Paper Mills Limited.

¹ Results of collections are given as of March 1977. Ed.