INTERNATIONAL PROVENANCE TRIALS OF EUCALYPTUS DEGLUPTA

During 1980–83, seed collections have been carried out in natural stands of Eucalyptus deglupta Blume in the West and East New Britain Provinces of Papua New Guinea. The collections have been done within the framework of an FAO/Office of Forests, Papua New Guinea cooperative programme on the collection of forest tree seeds.

By a circular letter dated 31 September 1983 addressed to potentially interested member governments, FAO's Forestry Department announces the availabity of seed from these collections for international provenance trials.

A total of 15 provenances (with seed collected from a minimum of 10 mother trees in each provenance) are available for international provenance trials in interested countries (see Table 1). In addition, a seedlot from a clonal seed orchard established in Papua New Guinea using select material of E. deglupta of Warangoi (New Britain) provenance, will be available for inclusion in the trials (28 mother trees, selected for good growth and form)¹.

The proposed trials will be coordinated by the Office of Forests, Papua New Guinea, in consultation with FAO's Forestry Department.

The establishment of trials using the full basic set of 16 seedlots (15 natural provenances plus the seed orchard seedlot), is recommended for countries interested in testing the species. If local plantations of E. deglupta of natural or introduced origin already exist in the participating country, seed from these should be included as a “control” in the experiments. Another locally widely planted or proven eucalypt species could also serve as “control”.

The trials design recommended is Randomized Complete Blocks(RCB). The number of Papua New Guinean seedlots available (16) also lends itself to the establishment of a Balanced Square Lattice, which would be an acceptable alternative to the RCB ².

It if of utmost importance to choose a trial site where there are no systematic environmental differences across the experimental site, or to lay out the blocks so that any such variation is eliminated. This is especially important in E. deglupta, which is a very site-sensitive species. It is also important to choose a site representative of potential future plantation areas.

It is recommended to establish the trials using 6 replications of 36-tree plots, with a 1-tree plot surround (giving an inner measurement plot of 16 trees). Recommended spacing is 3 × 3 metres, or alternatively 4 × 4 metres. With 16 treatments and 6 replications of 36-tree plot planted at a spacing of 3 × 3 metres, the total area of each trial will be 3.1 ha, plus buffers. If a spacing of 4 × 4 metres is adopted, the area needed for each RCB trial will be 5.5 ha, plus buffers.

It is recommended to establish randomized blocking already in the nursery to attain maximum precision in the estimation of genetic parameters and differences between the provenances tested. The nursery replications should be confounded with replications in the field, i.e. plants in any one field replication (block) should all come from the same nursery replication.

All randomization should be done using tables of random permutations or a similar, fully objective procedure.

Trials may be established on more than one site per country, resources permitting.

Countries interested in receiving seed for testing of Eucalyptus deglupta from the collections, and which have not yet responded to our circular of 31 September mentioned above, are advised to write to:

Office of Forests, Attention Mr. N.H.S. Howcroft,
Forest Research Station,
P.O. Box 134, Bulolo,
Morobe Province,
Papua New Guinea

(With a copy of the letter addressed to: the Director, Forest Resources Division, Via delle Terme di Caracalla, I-00100 Rome, Italy).

The following information should be provided:

1. Do you wish to establish the trials on more than one site and, if so, how many?

2. What are the latitude, longitude, altitude and climatic and soil conditions of each proposed experimental site?

3. Have species or provenance trials of E. deglupta or other tropical eucalypts already been successfully established in the areas proposed? Will locally collected seed be included in the trials and, if so, what species, provenance?

4. In which month do you wish to receive the seed? (Please also be sure to specify with greatest accuracy the name of the receiver and the address).

5. Are any import permits required for research quantities of tree seed?

General information on the species is given below.

¹ See General Information on E. deglupta on p. 17.

² Five replications are needed for a Balanced Square Lattice with 16 treatments.

EUCALYPTUS DEGLUPTA Blume - General Information ¹

Eucalyptus deglupta, commonly known as “Kamarere” (Papua New Guinea), “Bagras” (Philippines), or “Kaju Leda” (Indonesia), has a wide pan-tropic distribution extending from Mindanao in the Philippines; Ceram, Sulawesi, Irian Jaya and - according to some accounts - Timor and Flores in Indonesia; to Papua New Guinea (Coastal New Britain, Vanimo region, Morobe region, Raba Raba, Papuan South Coast and parts of the Highlands).

The species occurs naturally on soils from a wide range of parent materials, from acidic pumice to alluviums, but the optimum conditions appear to be on deep, rich, welldrained soils, with a non-seasonal rainfall of around 3 000 mm, temperature ranges of 20 to 32° C and an altitudinal range of 0–1,800 m a.s.l. It is not frost tolerant, and is highly susceptible to fire.

Eucalyptus deglupta grows into a large, usually straight tree up to 75 metres high and 2.5 metres in diameter.

In Papua New Guinea, E. deglupta is the main species grown on clear-felled rainforest sites in the coastal lowlands. It is a pioneer species and regenrates well on disturbed sites and natural clearings such as river, pumice or gravel beds, landslides and volcanic blast areas. On good sites it is capable of maintaining a mean annual increment of 2–3 cm in diameter during the first 10 years.

The wood of E. deglupta saws, planes and polishes well and is useful for general construction, boat-building, furniture joinery, plywood, panelling, flooring, poles and pulp. It is amenable to pressure treatment.

E. deglupta ranks high among the fastest growing tropical lowland forest species.

¹ Based on note prepared by the Office of Forests, Papua New Guinea.