Earlier reseach activities

Drought Adaptation and Genetic Diversity of Eucalyptus microtheca (1995-2000)

Researcher: Chunyang Li
Supervisor: Prof. Olavi Luukkanen

In January 1995, a five-year Ph.D. study was started at Department of Forest Ecology/Tropical Silviculture Unit, University of Helsinki. This study attempts to improve the understanding of the growth performance of Eucalyptus microtheca populations on the basis of their physiological behaviour and genetic diversity, and of the climatic conditions in their natural habitats. Such information could be useful in formulating future genetic improovement programs.

In  drylands, water availability is the main environmental factor controlling growth and survival. Depending on the severity and frequency of drought in natural habitats, there are different ecological selection pressure towards morphological and physiological behaviour that enable plants to continue their growth and survival. These processes of natural selection lead eventually to genetically differentiated among populations, if the gene flow among them is restricted.

So far, greenhouse experiment and laboratory work have been completed, the results show that morphological and physiological responses to water deficit conditions are different among populations; population differences are attributed to climate of native habitats and its drought adaptation is correlated with minimum seasonal rainfall; cluster analysis based on unbiased genetic distance and the UPGMA dendrogram revealed high genetic similarity among natural populations.

Later, cytological and molecular evolution of E. microtheca will also be studied.

Rehabilitation of forest ecosystems in Southeast Asia (1996-1999)

Prof. Olavi Luukkanen (project leader)
Jarkko Koskela, Riikka Otsamo and Jouni Suoheimo (researchers)

The vast extent of natural tropical forests and especially the alarmingly increasing area of degraded and deforested land make it essential that, in tropical forestry research, considerably more emphasis than before be put on the ecology of forest degradation and rehabilitation. Several UNCED follow-up processes and the ongoing consolidation of tropical forest policy  in the EU point to this fact. The Finnish development cooperation also aims at integrated development in which forests and forestry are seen as components of the environment, and natural resources are developed and managed in harmony with other land-related activities.

The management of natural forests has generally not yet shown the same positive trends as the planted tree cover in which private initiatives by farmers and enterprises have led to success. The poor performance of tropical silviculture for natural forests was in the past influenced by a general lack of knowledge of forest dynamics. New silvicultural practices should ideally be developed and tested in simple ecosystems. In the tropical forests of Southeast Asia, the natural pine forests present a uniq system for research, and preliminary outlines of their improved management have already been presented by us for the case of Thailand. In the case of Indonesia, with at least 20 million ha of degraded grasslands and a new wave of destruction being caused by forest fires, the question of second-rotation plantation management has become urgent. In our previous work, it was tentatively demonstrated that the local climax tree species could be used for restoration of the natural forest cover after a first rotation of fast-growing  trees. If this result could be further corroborated, this silvicultural approach would have great significance for tropical forest management world-wide.

The project focused on (1) rehabilitation and improved management of well-defined types of degraded forests of great importance for environmental conservation and economic development in Southeast Asia, especially by studing the critical ecological factors which limit the silvicultural interventions; (2) providing the follow-up of the forestry development projects supported by Finland in Thailand and Indonesia with research results that are immediately applicable; and (3) maintaining a Finnish research capability in tropical silviculture for the benefit of future development projects and for strengthening of the institutional linkages between forest researchers in Finland and Southeast Asia. In addition, a separate study for improving the silvicultural management of sal (Shorea robusta) forests in Nepal was carried out.

Case studies:

  1. Mixed pine forests in northern Thailand:Growth of grass-stage Pinus merkusii seedlings as affected by interaction between structure and function.
  2. Reforested Imperata grasslands in South Kalimantan, Indonesia: Integration of indigenous tree species into fast-growing forest plantations on Imperata grasslannds in Indonesia

Doctoral dissertations:

Koskela, J. 2000. Growth of grass-stage Pinus merkusii seedlings as affected by interaction between structure and function. Univ. Helsinki Tropical Forestry Rep. 20.

Otsamo, R. 2000. Integration of indigenous tree species into fast-growing forest plantations on Imperata grasslannds in Indonesia. Univ. Helsinki Tropical Forestry Rep. 21.

Suoheimo, J. 1999. Natural regeneration of sal (Shorea robusta) in the Terai region, Nepal. Univ. Helsinki Tropical Forestry Rep. 19.

Otsamo, R., Ådjers, G., Hadi, T.S., Kuusipalo, J. and Otsamo, A. 1996. Early performance of 12 shade tolerant tree species interplanted with Paraserianthes falcataria on Imperata cylindrica grassland. Journal of Tropical Forest Science 8(3): 381-394.

Otsamo, R., Kurniati, L. and Otsamo, A. 1996. Dipterocarp species on Imperata cylindrica dominated grasslands: a case study from South Kalimantan, Indonesia. In: Suhardi, I. (ed.). Proceeding of seminar on ecology and reforestation of dipterocarp forest in Gadjah Mada University, Yogyakarta, Indonesia, 24-25 January 1996. Faculty of Forestry, Gadjah Mada University and Kansai Environmental Engineering Centre. pp. 147-157.

Otsamo, R. 1998. Removal of Acacia mangium overstorey increased growth of underplanted Anisoptera marginata (Dipterocarpaceae) on an Imperata cylindrica grassland site in South Kalimantan, Indonesia. New Forests 16: 71-80. Abstract

Otsamo, R. 1998. Effect of nurse tree species on early growth of Anisoptera marginata Korth. (Dipterocarpaceae) on an Imperata cylindrica (L.) Beauv. grassland site in South Kalimantan, Indonesia. Forest Ecology and Management 105: 303-311. Abstract

Otsamo, R. and Kurniati, L. 1999. Early performance of ten timber species planted under Acacia mangium plantation on an Imperata cylindrica grassland site in South Kalimantan, Indonesia. International Tree Crops Journal 10(2): 131-144. Abstract

Otsamo, R. 2000. Early development of three planted indigenous tree species and natural understorey vegetation in artificial gaps in an Acacia mangium stand on an Imperata cylindrica grassland site in South Kalimantan, Indonesia. New Forests 19: 51-68. Abstract

Otsamo, R. 2000. Secondary forest regeneration under fast-growing forest plantations on degraded Imperata cylindrica grasslands. New Forests 19: 69-93. Abstract

Other related publications:

Otsamo, R. 1996. Integrating indigenous tree species in forest plantations on Imperata cylindrica grasslands – results from Riam Kiwa, South Kalimantan. In: Otsamo, A., Kuusipalo, J. and Jaskari, H. (eds.). Reforestation: meeting the future industrial wood demand. Proceedings of a seminar held in Jakarta 30 April and 1 May 1996. Reforestation and Tropical Forest Management Project (ATA-267). Ministry of Forestry, Forestry Research and Development Agency. Enso Forest Development Ltd, FINNIDA. Jakarta. pp. 87-95.

Otsamo, R., Ådjers, G., Kuusipalo, J., Otsamo, A., Susilo, N. and Tuomela, K. 1996. Effect of nursery practices on seed germination of selected dipterocarp species. Journal of Tropical Forest Science 9(1): 23-34.

Otsamo, R., Otsamo, A. and Ådjers, G. 1996. Reforestation experiences with dipterocarp spieces on grassland. In: Schulte, A. and Schöne, D. (eds.). Dipterocarp Forest Ecosystems – Towards Sustainable Management. World Scientific, Singapore. pp. 464-477.

Otsamo, R. and Otsamo, A. 1999. Early development of seedlings of six tree species after a rotation of Acacia mangium on an Imperata cylindrica grassland site in South Kalimantan, Indonesia. International Tree Crops Journal 10(2): 145-160.

Studies on interaction theory of agroforestry: Coexistent gain of populations

The project, studied by Dr. Wending Huang , will develop the theoretical concept of coexistence gain of populations, the model system for describing and simulating the coexistence-based interaction of populations in agroforestry systems, and analysed the with collected comprehensive data, in Jiangsu Province, China. The theoretical framework of the study will form a new approach to deeper understanding and evaluating of agroforestry systems. The modelling systems, e.g. coexistence gain model and interaction model, will contribute to the more firm and scientifically tested basis for design and management of agroforestry systems and help to describe and predict the performance of different agroforestry systems. The output of the research will directly contribute to optimal agroforestry planning,  designing and management, with practical significance for using limited arable land to produce more food for a large rural population.

Carbon and nitrogen dynamics in Erythrina poeppigiana (Leguminosae: Phasoleae) trees managed by periodic prunings

Doctoral dissertation project of Pekka Nygren 1991 – 1994, financed by the Academy of Finland and the University of Helsinki

The research was conducted in cooperation with the Nitrogen Fixing Tree Project of the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE) in Turrialba, Costa Rica.

The management of many agroforestry systems includes periodic prunings of the tree component, e.g. for fuelwood, forage or green manure harvesting. The selection of the pruning interval is an optimisation problem in which the desired harvest is maximized within the limits set by the resprouting capacity of the trees. Different management objectives call for different pruning intensities, e.g. in forage production the pruning interval is quite high to maximize the proportion of leaf harvest, while it may be rather long in fuelwood harvesting to promote branch growth. Below an example is given on the management of Erythrina poeppigiana in an alley cropping system with two consecutive maize crops per year in the experimental farm of CATIE in Turrialba, Costa Rica.

Doctoral dissertations:

Nygren, P., Kiema, P. & Rebottaro, S. 1996. Canopy development, CO2 exchange and carbon balance of a modelled agroforestry tree. Tree Physiology 16: 773 – 745. Full text in pdf

Nygren, P. 1995. Above-ground nitrogen dynamics following a complete pruning of a nodulated woody legume in humid tropical field conditions. Plant, Cell and Environment 18: 977 – 988. Abstract

Nygren, P. & Ramírez, C. 1995. Production and turnover of N2 fixing nodules in relation to foliage development in periodically pruned Erythrina poeppigiana (Leguminosae) trees. Forest Ecology and Management 73: 59 – 73. Abstract

Nygren, P. 1995. Leaf CO2 exchange of Erythrina poeppigiana (Leguminosae: Phaseoleae) in humid tropical field conditions. Tree Physiology 15: 71 – 83.

Nygren, P., Rebottaro, S. & Chavarría, R. 1993. Application of the pipe model theory to non-destructive estimation of leaf biomass and leaf area of pruned agroforestry trees. Agroforestry Systems 23: 63 – 77. Abstract

Other related publications:

Nygren, P. & Jiménez, J.M. 1993. Radiation regime and nitrogen supply in modelled alley cropping systems of Erythrina poeppigiana with sequential maize – bean cultivation. Agroforestry Systems 21: 271 – 285. Abstract

Nygren, P. 1993. Un modelo de los patrones de sombra de árboles manejados con podas periódicas en sistemas agroforestales. [Simulation of the shading pattern of periodically pruned trees in agroforestry systems]. Pesquisa Agropecuária Brasileira 28: 177 – 188. (In Spanish with English abstract) Full text

Nygren, P., Maraux, F. & Sánchez, G.A. 1993. Transmisión de la radiación solar en la copa de Erythrina poeppigiana (Walpers) O.F. Cook. [Solar radiation transmission in the canopy of Erythrina poeppigiana (Walpers) O.F. Cook]. Pesquisa Agropecuária Brasileira 28: 167 – 176. (In Spanish with English abstract) Full text

Research component in the Bura Fuelwood Project, Kenya 1984-1993

Continuous field studies in Kenya in 1984-1993 led to the largest project to date of the Unit and created its special knowledge in tropical dryland forestry. In the semi-arid Tana River basin in eastern Kenya and in co-operation with researchers from the Kenya Forestry Research Institute (KEFRI), management methods and the species selection for irrigated fuelwood plantations were investigated so as to improve the integration of forestry with irrigated agricultural schemes. Other research topics included rehabilitation of the degraded savanna vegetation using rainwater harvesting, and eco-physiological and genetic studies on the water utilisation and adaptation of an introduced eucalypt species both in the irrigated plantations in Kenya and over its natural range of distribution in Australia. The traditional use trees at the Tana River was an additional topic jointly studied by Finnish and Kenyan researchers and the local communities.

Microcatchment water harvesting improves the establishment and early growth of planted seedlings. The woody biomass yields for the best species under the best designs (1.0–2.8 m3 ha-1 a-1) exceed that of the natural vegetation. Water harvesting can be used for small-scale tree planting in dryland rehabilitation, but it is not applicable in supplying fuelwood for concentrated populations. The methods can be improved by increasing the number of seedlings per catchment, selecting suitably sloping sites, or by combining them with other water conservation measures, such as mulching or planting along contours.

Peer reviewed articles and monographs:

ANTTILA, L., ALAKOSKI-JOHANSSON, G.M. & JOHANSSON, S.G. 1993. Browse preference of Orma livestock and chemical composition of Prosopis juliflora and nine indigenous woody species in Bura, eastern Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 83–90. Abstract

JOHANSSON, S.G. 1993. Growth of irrigated Azadirachta indica, Cassia siamea and Prosopis juliflora in relation to stand density. – East African Agriculture and Forestry Journal 58 (Special Issue): 49–57. Abstract

JOHANSSON, S. 1995. Forestry in irrigated agricultural schemes with special reference to the Bura Irrigation and Settlement Project, Kenya. University of Helsinki Tropical Forestry Reports 10. 115 p. (Doctoral thesis). Abstract

JOHANSSON, S.G & KAARAKKA, V. 1993. Growth and yield of six-year-old fuelwood species under irrigation in eastern Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 23–34. Abstract

KAARAKKA, V. 1996. Management of bushland vegetation using rainwater harvesting in eastern Kenya. Acta Forestalia Fennica 253. 93 p. (Doctoral thesis). Abstract

KAARAKKA, V. & JOHANSSON, S.G. 1993. Early development of Eucalyptus tereticornis provenances exposed to irrigation. – East African Agriculture and Forestry Journal 58 (Special Issue): 43–47.

KAARAKKA, V & MAUA, J.O. 1993. Rainwater harvesting as a method for bushland rehabilitation with selected indigenous and exotic tree species.  – East African Agriculture and Forestry Journal 58 (Special Issue): 59–69. Abstract

OTSAMO, R, JOHANSSON, S. & LUUKKANEN, O. 1993. Dynamics of floodplain forests at Bura, Tana River, Kenya: results from a permanent sample plot study. – East African Agriculture and Forestry Journal 58 (Special Issue): 71–82.

SUMANEN, J. 1993. Production costs and feasibility of growing Prosopis juliflora in irrigated plantations in Bura, Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 91–99. Abstract

TUOMELA, K., JOHANSSON, S.G., KUUSIPALO, J. &  LUUKKANEN O. 1993. Morphological and physiological comparison of three provenances of Eucalyptus microtheca grown in eastern Kenya. – East African Agriculture and Forestry Journal 58  (Special Issue): 35–41.

VERTANEN, A., JOHANSSON, S., KAARAKKA, V. SARAJÄRVI, I. & SARKEALA, J. 1993. Biomass equations for Acacia reficiens, Acacia zanzibarica and Prosopis juliflora, and volume equations for Eucalyptus camaldulensis and Terminalia brownii. – East African Agriculture and Forestry Journal 58 (Special Issue): 13–21.

Other articles:

ESKONHEIMO, A.-K., ALAKOSKI-JOHANSSON, G.M. & JOHANSSON, S.G. 1993: Folk-knowledge on Prosopis juliflora and Azadirachta indica.East African Agriculture and Forestry Journal 58 (Special Issue): 119–124.

LUUKKANEN, M.O. & ODERA, J. 1993: Forestry research at Bura, Tana River District, Kenya, 1984–1993. – East African Agriculture and Forestry Journal 58 (Special Issue): 7–11.

MAUA, J.O. & OTSAMO, A. 1993. Utilization of Prosopis juliflora for charcoal production in Bura Irrigation and Settlement Project in eastern Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 115–117.

MWENDWA, A.K., OTSAMO, A. & OTSAMO, R. 1993. Effect of irrigation on soil nutrient status on a 14-month-old Prosopis juliflora and Eucalyptus microtheca  plantation in Bura Irrigation Scheme, eastern Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 101–105.

ODERA, J.A. & KUUSIPALO, J. 1993: Dry-land forestry: research problems and priorities. – East African Agriculture and Forestry Journal 58 (Special Issue): 7–11.

OJALA, J., JOHANSSON, S.G., KAARAKKA, V. &  OTSAMO, A. 1993. Effect of singling coppice in irrigated Prosopis juliflora at Bura, Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 107–110.

OTSAMO, A. & MAUA, J.O. 1993. Observations on pod production of planted Prosopis juliflora in Bura, Tana River District, Kenya. – East African Agriculture and Forestry Journal 58 (Special Issue): 111–114.

Technical reports :

Gachathi, N., Alakoski-Johansson, G. & Johansson, S. 1987. A check-list of indigenous trees and shrubs of Bura, Tana River District , Kenya with Malakote, Orma and Somali names. Univ. Helsinki and KEFRI.

Johansson, S. 1985. Forestry Development in the Bura Irrigation Settlement Project. Final Report for 1984. Univ. Helsinki and KEFRI.

Kamoni, P.T., Gicheru, P.T. & Ekirapa, A.E.E. 1987. Semi-detailed soil survey of a part of Bura West Fuelwood Plantation Project. Semi-detailed soil survey Report No. 1987, Soil survey, National Agricultural Laboratories, Min. of Agriculture, Nairobi .

Mäkelä, M., Johansson, S. & Luukkanen, O. 1985. Success of amenity tree painting at the Bura Irrigation Settlement Project. Univ. Helsinki and KEFRI.

Sarajärvi, I., Johansson, S. & Luukkanen, O. 1985. Biomass functions for irrigated Prosopis Juliflora plantations in Tana River District, Kenya. Univ. Helsinki and KEFRI.

Sarkeala, J., Johansson, S. & Luukkanen, O. 1985. Volume functions for Eucalyptus camaldulensis and Terminalia brownii in irrigated fuelwood plantations in Tana River District , Kenya . Univ. Helsinki and KEFRI.

Vertanen, A., Johansson, S. & Luukkanen, O. 1986. Biomass equations for two indigenous Acacia species (Acacia reficiens and Acacia zanzibarica) with special reference to the composition and Biomass of the savanna forest in Bura, Tana River District, kenya . Univ. Helsinki and KEFRI.

University of Helsinki Tropical Forestry Reports:

Johansson, S., Kaarakka, V., Luukkanen, O. & Mulatya, J. 1990. Forestry in Irrigation Schemes I. Research activities at Bura , Kenya 1984-87. Univ. Helsinki Tropic. Forest. Report 4.

Kaarakka, V., Johansson, S., Luukkanen,O. & Maingi, J. 1990. Forestry in Irrigation Schemes II. Research activities at Bura, Kenya 1988-89. Univ. Helsinki Tropic. Forest. Report 5.

Otsamo, A., Laxén, J., Johansson, S., Kaarakka, V., kuusipalo, J., Luukkanen, O. & Odhiambo Maua, J. 1993. Forestry Research in Bura , Kenya 1984-1993. Final Report of the Research component in Bura Fuelwood Project. Univ. Helsinki Tropic. Forest. Report 8.

Laxén, J., Koskela, J., Kuusipalo, J. & Otsamo, A. (eds.) 1993. Proceedings of the Bura Fuelwood project research seminar in Nairobi 9-10 March, 1993. Univ. Helsinki Tropic. Forest. Report 9.