Régénération and Nitrogen Fixation by Silver Wattle after Logging

 

 

  1. melanoxylon, hâve been extensively studied and planted in Asia and Southern Africa (Gleason 1986, Boland 1989, Awang et a/. 1993, Brown and Ho 1997), relatively little is known about silver wattle or its potential for biomass or timber production.

Silver wattle oceurs naturally across a broad géographie range in south-eastern Australia. Il favours areas where mean annual rainfall ranges from 600 mm to 1000 mm and mean températures range from a maximum of 20-28°C to a minimum of 0°C (Boland et al. 1989). It can tolerate severe frosts, with seedlings able to withstand températures of -7.5°C (Pollock 1986, Yang et al. 1994). In optimum conditions of high rainfall, well drained and fertile soil it may reach 35-40 m in height.

At Tanjil Bren, in the Central Highlands of Victoria, the Department of Natural Resources and Environment established a silvicultural Systems project in 1987-90. This is a highly productive area with a mean annual rainfall of 1900 mm and deep, well drained soils. Mountain ash is the dominant tree in the unlogged forest, regenerated from the 1939 bushfires, with silver wattle occurring as a tall understorey tree (Fig. 1). In younger (<10 years old) régénération mountain ash and silver wattle both dominate and there is intense inter- and intra-species compétition. The project was established primarily to investigate the effect of alternative harvesting and site préparation methods on mountain ash. However, il also provided a unique opportunily to study the régénération, growlh and nitrogen fixation of silver wattle.

Objectives of the Research

Two key questions were investigated:

  • Did silver wattle fix enough nitrogen to replace that lost during elear felling and slash burning?
  • Did alternative silvicultural Systems reduce the regenertion and nitrogen fixing potential of silver wattle?

Results and General Comments

Four coupes harvested 4 years previously were selected, two that had been prepared by burning and two that had been prepared using mechanical disturbance. On each coupe three blocks of three plots of 16 m2 were established in areas with different stocking of silver wattle. Each set of plots covered an area with varying numbers of dominant silver wattles with one plot of low stocking: no dominant wattles, onc of medium stocking: 1-3 dominant wattles and one of high stocking of silver wattle: 4 or more dominant wattles. Average numbers of stems for plots with moderate and high stocking were 2400 stems ha’1 and 5400 stems ha-1 respectively.

To détermine the amount of N fixed by silver wattle, the 15N natural abundance method was used (Shearer and Kohl 1986). The proportion of nitrogen derived from fixation in silver wattle aged 5 years was 58% and the average amount of N derived from Nz-fixation was 80 kg ha’1 for moderate stocking and 140 kg ha1 for high stocking (Fig. 2).

The abundance of ISN in soil decreased as stocking of silver wattle increased, indicating that some of the N fixed by silver wattle had been incorporated into the soil through root turnover, litterfall and tree mortality. Total amounts of N derived from N2-fixation in soil and végétation were 240 kg ha’1 for moderate stocking and 470 kg ha’1 for high stocking on mechanically disturbed coupes and 330 kg ha1 for moderate stocking and 760 kg ha-1 for high stocking of silver wattle on burnt coupes.

Stocking of wattle

Figure 2. N derived from Ns-fixation in soil and in above-ground wattle biomass for low, moderate and high stocking of silver wattle aged 5 years on mechanically disturbed coupes and burnt coupes.

 

The N loss after timber harvesting and slash burning is about 880 kg ha1. Over an 80-year rotation additions through rainfall and non-symbiotic fixation amount to 450 kg ha1, leaving a déficit of 430 kg ha’1 (Attiwill 1984). In the first 5 years silver wattle at high stocking will make up the entir déficit and at moderate stocking it will make up over 75% of this déficit. Thus over an 80-year rotation silver wattle will almost certainly make up the N déficit due to timber harvest and slash burning provided that stocking is at least 2400 stems ha1.

Dominant silver wattle grew at least as fast as dominant mountain ash. Average height of dominant wattle at âge 6 years was 11 m and average mass above-ground was 13 kg with the stem rnaking up 90% of the total. Total biomass of dominant silver wattle and mountain ash increased with increasing stocking of silver wattle from an average 65 tonne ha 1 at low stocking to 94 tonne ha’1 al high stocking (Fig. 3). Therefore productivity of a mixture of silver wattle and mountain ash in the régénération was 45% greater than productivity of pure mountain ash.

Figure 3. Above-ground biomass of dominant silver wattle and mountain ash at âge 6 years for different stocking classes of silver wattle.

 

To study the effect of alternative silvicultural Systems on régénération of silver wattle, stocking and growlh of silver wattle was assessed across the coupes involved in the Silvicultural Systems Project. Average stocking of dominant silver wattle at 3 years on clearfelled burnt coupes of 2 ha or

 

Message from the Coordinator
WP 2.08.02

Khongsak Pinyopusarerk

CSIRO Forestry and Forest Products

PO Box E4008, Kingston, ACT 2604, Australia

Tel: +61 2 6281 8247

Fax:+61 2 6281 8266

Email: Khongsak.Pinyopusarerk@ffp.csiro.au

Farm forestry is becoming popular in both developing and developed countries. Trees are important components in increasing farm productivity and products diversity in rural communities. NFT species hâve made a significant contribution to farm forestry expansion. Hence research and development on nitrogen fixing trees continues to receive wide interest, especially for intégration on farms and establishment of woodlots. Tne volume of publications in seminar proceedings and international and national journals indicates the interest of scientific community in the NFT species.

During 7-13 August 2000, the XXI IUFRO World Congress was held in Kuala Lumpur, Malaysia. A total of 1906 delegates from 96 countries attended. Posters and oral présentations were offered during the congress. NFT species had an important place, especially in the

^^oster session. Thus, I take this opportunity to congratulate those who contributed towards the promotion and development of NFT species. The présentation of those interesting results would not hâve been possible without generous support from many international and national agencies in providing financial assistance for research and sponsorships for participants to attend the congress. We certainly look forward to further support.

Once again I thank members for sharing information and research results in this issue. I am sure your contribution is appreciated by more than 1000 members in 98 countries.

Régénération and Nitrogen Fixation
by Silver Wattle after Logging

Barrie May

Plantation Forest Research Centre

Aiiport Rd

Mount Gambier

SA 5290 Australia

Tel: +61 8 8721 8120

Emai 1 : Barrie. May @ ffp .csiro. au

Introduction

Silver wattle (Acacia dealbata Link.) fixes nitrogen and provides habitat and food for a variety of wildlife species. It competes with economically important species such as mountain ash (Eucalyptus régnons) during the early years of régénération after logging or fire. It commonly regenerates after fire but also regenerates after other forms of disturbance. Although other acacias, such as A. mangium, Â. mearnsii and

Figure 1. Silver wattle and mountain ash aged 50 years growing in near Tanjil Bren in the Central Highlands of Victoria, Australia.

more was 2500 stems ha1 (approximately equal to that on plots with moderate stocking). Silvicultural Systems using smaller coupe sizes or retaining mature trees reduced stocking to less than 100 stems ha1 and resulted in poorer growth and thus reduced nitrogen fixation. Burning favoured initial régénération of silver wattle, but also increased inter- and intra-species compétition, so that by 6 years above-ground biomass of silver wattle was less on burnt coupes than on un burnt coupes.

Silver wattle is a fast growing coloniser after disturbance and able to tolerate a wide range of conditions. This study showed that it can fix large quantifies of nitrogen, is highly productive, but that it is sensitive to compétition from mature trees. It performs an essential rôle in maintaining the N balance in the mountain ash ecosystem as well as in providing food and habitat for wildlife. Further research is needed to assess its growth and N-fixing performance on poorer sites as well as to investigate its value for speciality timber as well as pulp. However, it should at least be considered as an potential species for forestry plantations either in a monoculture or in a mixture with other trees.

C’

V

References

Attiwill, P. M. 1984. Effects of fire on forest ecosystems. In Landsberg, J. J. and Parsons, W. (eds.) Research for forest management: proceedings of a conférence organised by the Division of Forest Research, CSIRO, Canberra, 249-268.

Awang, K. and Taylor, D. (eds.) 1993. âcæczïz mangium: growing and ulilization. Winrock Internationa! Institute for Agricultural Research, Forestry/Fuelwood Research and Development Project (F/FRED) and FAO, Bangkok, Thailand.

Boland, D. J., Brooker, M. I. H., Chippendale, G. M., Hall, N., Hyland, B. P. M., Johnston, R. D., Kleinig, D. A. and Turner, J. D. 1989. Forest trees of Australia. Nelson, South Melbourne. 687 pp.

%5oland, D. J. (ed.) 1989. Trees for the tropics: growing Australian multipurpose trees and shrubs in developing countries. ACIAR Monograph No. 10, Australian Centre for International Agricultural Research,Canberra.

Brown, A.G. and Ho, C. K. 1997. Black wattle and its utilisation: abridged English édition. RIRDC Publication, No. 97/72 – Rural Industries Research and Development Corporation (Kingston), Canberra.

Gleason, C. D. 1986. Tasmanian blackwood – its potential as a timber species. New Zealand Forestry. 31(1): 6-12.

Pollock, K. M., Greer, D. H. and Bulloch, B. T. 1986. Frost tolérance of Acacia seedlings. Australian Forest Research 16:337-346.

Shearer, G. and Kohl, D.H. 1986. Nitrogen-fixation in field settings: estimations based on natural l5N abundance. Australian Journal of Plant Physiology 13: 699-756.

Yang, M.Q., Zeng, Y.T., Zhang, X.J. and Zhang, X.S. 1994. Effect of low températures on Acacia. In Brown, A.G. (ed.) Australian Tree Species Research in China. ACIAR Proceedings No. 48, Australian Centre for International Agricultural Research, Canberra, pp. 176-179.

Editors’ note:

Silver wattle (Acacia dealbata) has been a successful exotic in several countries but is a serious weed in Chile, India and South Africa duc to its prolific seed production and suckering habit. For further details see Doran and Turnbull (1997). This book is available free of charge to bona-fide researchers in developing countries on application to Dr. J. Fryer, Forestry Program Manager, ACIAR, GPO Box 1571, Canberra, ACT 2601, Australia.

Doran, J.C. and Turnbull, J.W. (eds.) 1997. Australian trees and shrubs: species for land réhabilitation and farm planting in the tropics. ACIAR Monograph No. 24, Australian Centre for International Agricultural Research, Canberra.

International Provenance Trials of
Casuarina equisetifolia subsp.
equisetifolia

Khongsak Pinyopusarerk and Antoine Kalinganire

CSIRO Forestry and Forest Products

PO Box E4008, Kingston ACT 2604, Australia

Te!: +61 2 628: 8247

Fax:+61 2 6281 8266

Email: Khongsak.Pinyopusarerk@ffp.csiro.au

Antoine.Kalinganire@ffp.csiro.au

There are two subspecies of Casuarina equisetifolia: subsp. equisetifolia and subsp. incana (Wilson and Johnson 1989). Subsp. equisetifolia has a wide distribution on subtropical and tropical coastlines extending from south Thailand and Peninsular Malaysia to northern Australia, Melanesia and Polynesia. Subsp. incana occurs exclusively along the coast of Queensland and northern New South Wales of Australia. The two subspecies are distinguished by the length of the leaf teeth (0.5-0.7 mm in subsp. equisetifolia and 0.7-1.0 mm in subsp. incana) and the dense pubescent immature phyllichnia (ridge of a branchlet article) in subsp. incana.

Casuarina equisetifolia: subsp. equisetifolia is a nitrogen-fix- ing tree of considérable social, economical and environmental importance in tropical/subtropical littoral zones of Asia, the Pacific and Africa. It is commonly used in agroforestry Systems, for soil stabilisation and réclamation work and in Coastal protection and réhabilitation (Pinyopusarerk and House 1993). It is one of the most extensively introduced species outside its natural range to more than 60 countries especially in Asia, East and West Africa, the Caribbean and Central and South America. Some of the early introductions such as those to Cuba, India and Vietnam date back more than one hundred years. Planted areas in China, India and Vietnam alone exceed one million hectares. Despite such widespread planting the genetic background of the planting material is gcnerally unknown and little has been done to explore and exploit the genetic variabilily of the species.

 

Guidelines for Contributions

We encourage members of the NFT Working Party to share their expériences and research results with others. Please help to make this newsletter and the NFT Working Party successful by sending articles on relevant topics to us.

Content: IUFRO WP news, conférence reports, brief review or technical articles, letlers or comments related to improvement and culture of nitrogen fixing trees.

Language: The newsletter will be published only in English al présent. Ail submissions should be presented in English.

Text Format: Ail submissions may be sent by email or in print with a copy in Word file on a 3.5 diskette (PC or Mac). Typescripts or disks will not be retumed unless indicated.

Figures: Submit accompanying graphs. tables, charts, etc and captions in printed, camera-ready or electronic form. Slides and photographs will be accepted.

Submissions: Please address submissions to the WP Coordinator or Deputy Coordinator.

The newsletter will be available in print and from the IUFRO web page.

 

 

 

Publication

Dommergues, Y.R, Duhoux, E. and Diem, H.G. 1999. Nitrogen-fixing trees; fundamentals and applications with spécial référencé to the management of tropical and mediterranean ecosystems. 528 pp. Montpellier: Editions Espaces 34. FF590 (hardback).

This unique, single-source volume covers scientific, technical and praclical information on the use of nitrogen-fixing trees in the tropics and mediterranean zones. It is published in French by Editions Espaces 34 B.P. 2080, 34025 Montpellier Cedex 1 France (fax: 33 4 76 840074).

Important features include:

a comprehensive présentation of the most recent fundamental advances in our knowledge on the rhizobial, actinorhizal and mycorrhizal symbioses;

  • addressing the challenges of improving nitrogen fixation in the field (through microbiology, plant sélection using classical and modem methods, and through appropriate field practices);
  • discussion on the problems raised by the intégration of nitrogen-fixing trees into different ecosystems;
  • highlight of over 90 nitrogen-fixing species on botanical characteristics with drawings facilitating the identification without help of a specialized flora, ecological requirements, main uses, main pests and diseases, nitrogen-fixing symbioses and mycorrhizal symbioses; and
  • over 14 000 helpful Iitcraturc citations covering publications from well-known and also emerging scientific groups and extensive indexes (subject and botanical names) easing access to related information throughout the book.

 

 

 

days. The average of the two sets for each treatment was recorded as a percentage. The germination value was determined by using the formula for evaluating results of germination tests by Djavanshir and Pourbeik (1976) as shown below:

GV = DGs/N x (GPx 10), where

GV = Germination value

DGs = Daily germination speed, i.e. total germination percent/number of days since beginning of the test

N = Number of days since beginning of germination GP = Germination percent at test conclusion, i.e. number of

germinated seeds/100 10  = Constant

Results and Discussion

Cumulative germination results and germination values for fresh seeds and for 3-month-old seeds are given in Table 1. There was an effect of extraction methods on S. singueana seeds. Seeds extracted using the threshing machine generally gave a poor germination. The highest germination value was obtained with seed opened by hand and then soaked in cold water for 24 hours (Table 1).

Moreover seed pre-treatments affected germination results. Extraction of seed by hand improved germination. Seeds soaked in boilcd water gave poor germination compared to those soaked in cold water for 24 hours. Seeds had still high germination value three months after seed storage. Washing seeds after extraction broke down dormancy.

The results are similar to those reported by Bewley and Black (1994) in that 5. singueana seed has a biochemical dormancy rather than a physical dormancy. Extraction of seed by threshing machine resulted in poor germination, probably because the seed cracked with a subséquent death of the embryo during the extraction operation (Mussa et al. 1995). On the other hand, germination of seed macerated in tap water was as good as that of seed extracted by hand. Thus macération of fruits could be an alternative extraction method to hand extraction method which is expensive and time consuming.

Macération Control 68 72 3.2 8.5
  Cold water 24 hr 78 82 15.3 17.6
  Hot water 3 hr 57 80 7.5 11.5
Opened by hand Control 74 87 8.3 13.3
  Cold water 24 hr 90 86 23.0 25.5
  Hot water 3 hr 18 57 8.1 9.0
Thresher machine Control 69 49 9.2 6.9
  Cold water 24 hr 50 57 8.5 9.2
  1 lot water 3 hr 52 17 5.9 1.7
Table 1. Germination results and germination values of Senna singueana fresh seeds and at 3 months after seed extraction.
Extraction method Pre-trcalment method Cumulative germination Germination value (%>
Eresh seed 3 months Fresh seed 3 months

 

It can be concluded that for good germination results, S. singueana fruits should be extracted by hand and by washing seeds to remove pulp. However, manual extraction is time consuming and laborious. Thus water macération could be used as an alternative extraction method when extracting

large amount of fruits. Soaking 5. singueana seed in cold water for 24 hours is recommended before sowing.

References

Bewley, J.D. and Black, M. 1994. Seeds, physiology of development and germination. Plénum Press, New York and London.

Djavanshir, K. and Pourbeik, H. 1976. Germination value. A new formula. Silvae Genetica 25: 79-93.

Palgrave, K.C. 1977. Trees of Southern Africa. C. Struik Publishers, Cape Town, South Africa.

Pullinger, J.S. and Kitchin, A.M. 1982. Trees of Malawi with some shrubs and climbers. Blantyre Printer and Publishing, Blantyre, Malawi.

Mussa, W., Maliondo, S.M.S. and Msanga, H.P. 1995. Effect of seed coat scarification on germination of Acacia polyacantha seed. In: Olesen, K. (ed.) Proceedings of the IUFRO symposium of the project group P.2.04.00. ‘Seed Problems’, Arusha – Tanzania. Danida Forest Tree Seed Centre, Humlebaek, Denmark. p. 217-222.

Introduction of Acacia holosericea
in Pondicherry, India

Sri B.L. Das

Consultant on Forestry and Environment

Orissa

Cuttack 753 002, India

Fax: +91 671 618807

In India the introduction of Acacia holosericea in 1983 was more recent compared to other acacias, such as A. auriculiformis, which hâve been used for re-afforestation of degraded wastelands for many décades. Acacia holosericea was first introduced by the ‘Ecolake’ project for wasteland réhabilitation in Pondicherry, South India. The ‘Ecolake’ project started in 1979 with the main activity of establishing démonstration plots to local people on restoration of degraded land by planting fast-growing tree species. The use of forest products for income génération was also emphasised.

The area covered by the project is about 60 ha. The land is severely eroded with rocks and boulders at the surface. Deep gullies and ravines characterise the area rnaking it unproductive. For land restoration, many tree species, most of them nitrogen-fixing trees including A. holosericea and Casuarina junghuhniana, hâve been tried. Both species not only gave the best results, but A. holosericea also showed a profuse natural régénération from seeds.

The farmers in Pondicherry hâve shown interest in A. holosericea because it provides fuelwood, pôles and small timber for house construction. It is also an excellent fodder. Twelve tonnes ha’1 of fuelwood were produced on a four-year rotation. Therefore, the increased économie utilisation and its success in Pondicherry may warrant a small program of

 

Tree growth and biomass production were evaluated at 12 months after planting. After the measurement of total height and diameter at 50 cm from ground level, plants were harvested at ground level and biomass weighted and recorded.

Results and Discussion

The results for growth and biomass production at 12 months after planting are shown in Table 1. Différences between species were high for biomass. Although growth was similar for ail species, there was a tendency of better growth for L. diversifolia with a diameter of 2.3 cm, compared with L. leucocephala and A. angustissima with 1.9 cm and 2.2 cm respectively.

Table 1. Mean growth rates and green weight biomass production per plant at 12 months after plating.

Species Diameter

(cm)

Height

(m)

Biomass

(kg)

Leucaena leucocephala 1.9 2.7 9.0
Leucaena diversifolia 2.3 3.3 11.1
Acacia angustissima 2.2 3.6 28.1
Average 2.1 . 3.2 16.0
CV (%) 13.9 16.7 39.0

 

Biomass production showed différences among the three species and the Neuman-Keuls test confirmed significant différences between A. angustissima and two Leucaena species. No diseases or insect attacks were observed during the study.

Alley-cropping research is relatively new at Kipopo, compared with a long expérience in other countries. The results at Kipopo are applicable to areas of similar ecological conditions, e.g. Katanga in RDC. The results showed that the three species hâve different and interesting potential at Kipopo. Acacia angustissima can be used in soil restoration for its high biomass production. The species is also adapted to acidic and infertile soils and is drought tolérant. This acacia retains ils green foliage during the long dry season and will be

, good source of fodder for that period.

Leucaena leucocephala is suitable mainly for green manure, fodder and érosion control. In addition, A. angustissima and L. diversifolia can be used as alternative species to L. leucocephala as they are résistant to Leucaena psyllid (Heteropsylla cubana). The potential of Leucaena hybrids, e.g. L. palida and L. diversifolia as an alternative species to L. leucocephala should be investigated.

References

Kang, B.T. and Reynolds, L. 1989. Alley farming in the humid and subhumid tropics: Proceedings of an international workshop held at Ibadan, Nigeria, 10-14 March 1986. International Development Research Centre, Ottawa, Canada.

Effect of Extraction and Pre-treat-
ment Methods on the Germination
of Senna singueana (Delile) Seed

Kindo Abeid Idd

National Tree Seed Programme

P.O. Box 373, Morogoro, Tanzania

Fax: +255 56 3275

Email: ntsp@twiga.com

Introduction

Winter cassia, Senna singueana Delile var. glabra (E.G Baker) Brenan is a small leguminous tree up to 5m in height with a round crown, often showing damage from fire or browsing. Leaves are pinnate, 4 to 10 pairs of leaflets with conspicuous glands between each pair of leaflets, apex and base rounded and margins are entire. Flowers are bright yellow, conspicuous in large loose panicles. Flowering starts from April to September. It is one of the earliest trees to flower in spring (Palgrave 1977). Fruits are narrow, cylindrical, rather fleshy pod, slightly constricted between the seeds, yellow when ripe, drying to dark brown and splitting. Fruits are ready for collection between September to December. Pods and leaves are edible raw or cooked and can be used as a fodder (Pullinger and Kitchin 1982). Ash from the burnt roots mixed with porridge provides a remedy for stomach pains (Palgrave 1977). The species is being promoted in agroforestry Systems for restoration of soil fertility. Thus, there is a growing demand for seed.

Fruits of winter cassia can be extracted by different methods and different pre-treatments can be used germination. However, the most effective seed extraction and pre-treatment methods are not known. This study investigated the impact of different seed extraction and pre-treatment methods on the germination of S. singueana seeds.

Materials and Methods

The study was carried out at the National Tree Seed Centre, Morogoro, Tanzania. The mean annual rainfall is 580 mm and the mean monthly température is 26°C. Fruits were collected in September 1999 at Wami-Dakawa, Tanzania (6°23’S, 37°25’E, 930 m asl).

Three extraction and three pre-treatment methods were applied. For extraction: (1) macération of fruits with tap water, (2) open the fruits by hand and seeds thoroughly washed with tap water, (3) fruits sun-dried then crushed by threshing machine to separate the seed and fruit. For pre-treat­ment: (1) control – no treatment, (2) soaking in cold water for 24 hours and (3) soaking in hot water, c. 100°C and left to cool for 3 hours. For extraction methods 1 and 2, extracted seeds were sun dried to 9% moisture content. Following each extraction method, 200 seeds were used for germination test immediately, and another 200 seeds three months after storage in cloth bags at room température (25°C).

 

 

 

Sys, C. and Schmitz, A. 1959. Carte des sols et de la végétation du Congo-Belge et Ruanda-Urundi, Région d’Elisabelhville (Haut-Katanga), notice explicative. Publication de l’INEAC, Bruxelles, Belgique.

Seeds were germinated in containers filled with sand and moistened with tap water. The containers were kept in a germination room at room température (25-30°C). For each germination test, two sets of 100 seeds each were used. A seed was considered as germinated when the cotylédons had emerged above the soil surface. Observations were made at 12

 

Following a recommendation at the Second International Casuarina Workshop held in Cairo, Egypt in 1990, the CSIRO Australian Tree Seed Centre coordinated range-wide provenance seed collections of C. equisetifolia subsp. equisetifolia with financial support from the Australian Agency for International Development (AusAID). In total 67 seedlots were collected in 22 countries both within and outside the species’ natural distribution range during 1991-1993. The origin of these seedlots can be categorised into five broad régions : (1) natural distribution in Australia and the Pacific, (2) natural distribution in South-East Asia, (3) location of introductions in Asia, (4) location of introductions in Africa, and (5) location of introductions in the Caribbean. The seed has been used to establish more than 40 provenance trials in 20 countries in Asia (China, India, Indonesia, Malaysia, Pakistan, Sri Lanka, Taiwan, Thailand, Philippines and Vietnam), Africa (Egypt, Kenya, Malawi, Mauritius and Rwanda), Australia, Caribbean (Cuba), Central America (Honduras), and the Pacific (Fiji and Papua New Guinea). Guidelines for establishment and assessment were prepared and distributed to ail collaborators to ensure standardisation in this international sériés of provenance trials. Apart from height and diameter, other characteristics such as stem form, branching habit, health and reproduction hâve been included in the measurement. Early results of a small number of these trials were reported at the Third International Casuarina Workshop held in Da Nang, Vietnam in 1996 (Pinyopusarerk et al. 1996). While growth varied from site to site following prevailing local environmental conditions, there were elear différences between provenances in most of the growth parameters measured. In addition, différences between régions and between countries within régions were also found. Natural provenances from the South Fast Asian région appeared to grow faster than those from the other régions. However, no one provenance showed superior performance for ail the growth characteristics.

While results hâve been reported for individual trials by separate collaborators, CSIRO Australian Tree Seed Centre has embarked on determining the magnitude of génotype x site interaction. Growth data from 14 trials in 9 countries (Australia, China, Honduras, India, Kenya, Sri Lanka, Taiwan, Thailand and Vietnam) hâve now been selected for this purpose. The statistical analysis is nearly complété and a spécial report on the results of these international provenance trials will be prepared and published.

The performance of C. equisetifolia in plantations will not be optimised unless close attention is paid to sélection and improvement of the best genetic material. The wide géographie range and extensive planting of the species offer great potential for sélection for tree improvement programs. The multi-nalional provenance trials should provide very useful information of the best provenances for particular sites.

References

Pinyopusarerk, K. and House, A.P.N. 1993. Casuarina: an annotated bibliography of C. equisetifolia, C. junghuhniana and C. oligodon. International Centre for Research in Agroforestry, Nairobi, Kenya, 296 pp.

Pinyopusarerk, K., Turnbull, J.W. and Midgley, S.J. (eds.). 1996. Recent casuarina research and development: proceedings of the Third International Casuarina Workshop

held in Da Nang, Vietnam, 4-7 March 1996. CSIRO, Canberra.

Wilson, K.L. and Johnson, L.A.S. 1989. Casuarinaceae, Flora of Australia 3, 100-174. Australian Government Publishing Service, Canberra.

Performance of some NFT Species at Kipopo, Démocratie Republic of \   Congo

Jean-Pierre Jos Mulamba Apuku

Chef de Bureau Recherche

Institut National pour 1’ Etude et la Recherche Agronomiques

BR 2037 Kinshasa

Démocratie Republic of Congo (RDC)

Introduction

The ‘Institut National des Etudes et Recherches Agronomiques’ (INERA), Research Centre of Kipopo is situaled 25 km from Lubumbashi City (ll°34’S; 27°24’E). The area receives a mean annual rainfall of 1250 mm with a dry period of seven months from April to October.

The végétation which was once made up of savanna forest has undergone change due to forest burning, wood cutting, cattle grazing and food-crop growing as a resuit of high démographie density in the area (Sys and Schmitz 1959). These factors wnic’n affected the ecosystem can possib’y be restored by the use of multipurpose trees such as NFT species. Most studies on alley cropping were based on the impact of the System on soil fertility, the width of the alley cropping, the pruning of trees, the effect against weeds, the décomposition of straw, soil water conservation and management of manpower.

Results in other environments in tropical countries revealed that foliage produced by NFT species can be used to giv® better cereal yields than traditional Systems (e.g. Kang ak^yy Reynolds 1989). The présent study reports findings of a 12-month évaluation for an alley cropping trial located at Kipopo involving NFT species.

Materials and Methods

The NFT species used in the study are: Leucaena leucocephala var K8, L. diversifolia var K156 and Acacia angustissima Klutz. The seeds used in the study were provided by the ‘Programme National Maïs’, located at Lubumbashi.

Seeds were soaked in hot water prior to sowing. Pricking-out was in polyethylene bags filled with sieved forest soil. Germination was high for ail seedlots (>75%). Planting out was at 40 days after germination. Each species was planted in an alley consisting of two hedges 8 m long, and 3.5 m between hedges and 0.5 m within hedge, intercropped with maize. The experimenl was laid out in a randomised complété block design with 4 replicates.

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