STRATEGY OF TREE IMPROVEMENT AND FOREST GENE RESOURCES CONSERVATION IN NICARAGUA

by

Eduardo Ampié and Lars Ravensbeck
Centro de Mejoramiento Genetico y Banco de Semillas Forestales
Km. 12½ Carretera Norte
Managua
Nicaragua

INTRODUCTION

In Central America, Nicaragua covers approximately 130 000 km² of which 35 % are forested area according to the Forestry Action Plan of Nicaragua (FAP-NIC). The deforestation rate is the highest in Central America with about 100 000–150 000 ha/year mainly due to conversion to agriculture. This has a tremendous impact on the flora and fauna.

The forestry ecosystems in Nicaragua, as in many other regions of the world, are subject to severe degradation leading to genetic erosion. The conservation of forest genetic resources is difficult in a country where adequate forest conservation policies are missing, and this poses special challenges when using local species in long term genetic improvement programmes.

The Centro de Mejoramiento Genético y Banco de Semillas Forestales (CMG&BSF) of the Ministry of Environment and Natural Resources (MARENA), with the cooperation of the Danish International Development Administration (DANIDA), initiated in 1991 a strategy for seed supply, tree improvement and gene resource conservation in situ and ex situ. The strategy concerns native species and provenances of high commercial and/or socioeconomic value, which in addition are in danger of genetic depletion or, at times, extinction. Also exotic species of importance for forestry development in Nicaragua are included in the strategy. Within this strategy, seed and conservation stands have been established, mainly in the project area, 79 km northwest of the capital, Managua.

Objectives of the strategy

The strategy for seed supply, tree improvement and genetic conservation has the following objectives:

1. To procure and provide forestry germplasm of high quality and sufficient quantities to satisfy national and international demand.

2. Genetic improvement of forestry species of high commercial and/or socio-economic importance.

3. Conservation of important forestry species and provenances which are in danger of extinction and/or in the process of rapid genetic erosion.

4. Promotion of the use of forestry germplasm of high genetic quality and dissemination of results and information on forest tree improvement and gene resource conservation to users at both local and regional levels.

In regard to the objectives listed above, the following should be noted:

1. Improvement programmes will be elaborated at three levels of intensity, depending on the actual importance of the targeted species. Intensive work will be limited to those of maximum importance.

2. Seed stands and seed orchards are being demarcated or established for priority species identified. Collection from such seed production areas will reduce costs of harvesting and processing of seed, in addition to enhancing the genetic quality of the seed produced.

3. Seed sources which have already been identified, documented and tested in international provenance trials and which have demonstrated genetic superiority compared to other provenances, will be utilized, e.g. for Pinus patula ssp. tecunumanii and P. caribaea var hondurensis and Eucalyptus camaldulensis, which have already undergone testing at international level.

4. Genetic conservation efforts will form the basis for all tree improvement work, and will be carried out (i) in situ, for species and provenances of high priority and of proven genetic value; and (ii) ex situ, as a complement to in situ strategies for these same species and in some cases also for species of lower priority.

SELECTION OF SPECIES FOR THREE ECOLOGICAL ZONES

In 1991, a technical group of CMG&BSF, with the assistance of consultant George Gibson of the UK, elaborated the first strategy for tree improvement and genetic conservation in Nicaragua. This strategy, which concentrated on the dry zones of the country, originally included 19 native and 8 introduced forest tree species, for which the establishment of conservation stands and seed orchards was considered a priority.

The selection of species was based on the following:

• proven economic importance;
• high present and likely future demand for seed;
• multiple uses;
• danger of extinction and/or genetic erosion.

The relatively high number of species selected was due to the fact that many species were being used and/or recommended for use by the forestry sector in Nicaragua. Therefore, conservation of the diversity of forestry species and provenances was considered important.

In 1994 the strategy was revised and extended to cover the whole country. For implementation of the strategy, the country was sub-divided into three main, ecological zones: (i) the dry zone (25 000 km²); (ii) the pre-montane zone (20 000 km²); and (iii) the humid zone (75 000 km²). Forestry statistics showed that, by the end of 1992 Pinus caribaea var. hondurensis (humid zone) and Eucalyptus camaldulensis (dry zone) covered most of the total area of existing industrial plantations. However, during the past years a considerable increase in the use of the broad-leaved native species for high quality wood production or for agroforestry systems has been evident.

The Forestry Action Plan of Nicaragua (FAP-NIC) has proposed the establishment of a Centre of Forestry Development in central Nicaragua, to catalyze action, mainly in the humid and pre-montane zones. In the dry zone, forestry activities will mainly concentrate on the establishment of energy plantations and agroforestry systems.

Identification of priority species and determination of their level of importance, were based on the present forestry trends and prevailing demand of seeds (see Table 1.). It should be noted that intensity of action varies according to species.

Table 1. Priority species for the 3 main ecological zones

TREE IMPROVEMENT

Species trials form a basic component and a first step in any tree improvement programme, and help identify and test potential species in given ecological conditions. Such trials, the extent and intensity of which will depend on available financial and manpower resources, will in many cases complement more advanced tree improvement programmes, under way for already proven and identified priority species.

The testing of a range of provenances for species of high and intermediate priority is an essential step. For species of lower priority (i.e. species which are not likely to be included, in the short term, in plantation and improvement programmes), provenance trials will be established only if resources allow.

Levels of improvement

In the strategy, it was considered appropriate to work with three levels of tree improvement: an extensive level, an intermediate level and an intensive level. The intermediate level was developed for the following two reasons: (1) to ensure improvement of species of some importance though they were not included in the intensive programme and (2) to prepare a flexible genetic improvement programme in case of change of priorities.

At all three levels, a multiple population approach is considered, and conservation will be closely linked to improvement.

Extensive level

This level concerns species of minor importance. Seedling seed orchards or seed stands will be established with broad based genetic material collected from 50–100 non-related, phenotypically superior trees of the same provenance. This type of seed orchards or seed stands will serve both as breeding populations and as seed production stands.

The gain in relation to productivity is expected to be 2–5%; considerable additional improvement can be gained in survival, adaptability and form.

Intermediate level

This level concerns species of intermediate priority. Seedling seed orchards will be established using open pollinated progenies of 30–60 (in some cases more) selected, non-related plus trees. For each species several seedling seed orchards may be established. Initially, these seed orchards will also be used as progeny trials, to provide information on the genetic value of the mother trees.

The degree of improvement at this level will be larger than at the extensive level due to maintenance of the identity of each progeny in the orchard, coupled with genetic evaluation and subsequent roughing. The genetic gain in yield is expected to be 10–20%.

Intensive level

This level includes two species of high priority: Eucalyptus camaldulensis and Pinus caribaea. For these two species more elaborate improvement plans will be developed to maximize yields and other economic characteristics, and thus to enhance the benefits for the forestry sector in different ecological zones. In drawing up such improvement plans, economic and manpower resources available at the CMG&BSF will be realistically considered.

CONSERVATION OF FOREST GENE RESOURCES

Conservation of forest genetic resources in Nicaragua will be carried out both in situ and ex situ. In situ conservation will only be possible in areas where pressure on forestry resources allows their sustainable management. Complementary ex situ conservation will be needed in most cases. The strategy recognizes the need to identify priority species and provenances for conservation and the need for management of the resources to fulfil conservation needs. Urgent action is needed to conserve in situ some of the natural provenances of Pinus caribaea var. hondurensis, including the internationally important Alamicamba provenance. Other species of high economic value included in the strategy are Bombacopsis quinata, Swietenia humillis and Swietenia macrophylla.

Until now, Pinus patula ssp. tecunumanii, provenance Yucul, which proved to be the best provenance in the international trials carried out over the past decade, is the only species effectively conserved in situ by CMG&BSF.

Forest Genetic Resources No. 22. FAO, Rome (1994)
Manuscript received June 1994.