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Silvicultural management proposal for Alexander von Humboldt National Forest

C. Linares Bensimon

Carlos Linares Bensimon is chief silviculturist with the International Tropical Timber Organization (ITTO) Alexander von Humboldt National Forest Management Project (95/90 [F]). Pucallpa, Peru.

This article outlines a silvicultural management proposal for Alexander von Humboldt National Forest in the Pucallpa Amazon region of Peru.

The Alexander von Humboldt National Forest lies in the heart of the Amazon region, 685 km by road from Lima, the capital of Peru. The park now covers more than 470 000 ha of low-lying hills with an average temperature of 25°C and an annual rainfall of approximately 3 600 mm.

The Alexander von Humboldt National Forest was established by the Peruvian Government in 1965 for production forestry, which at the time was the statutory prerogative of the state. The situation changed in the early 1980s when access was granted to three private companies which currently exploit approximately 80 000 ha.

In the 1970s, with FAO assistance, a project was undertaken for the utilization of this forest. Under the project, surveys and detailed studies were carried out but these came to nothing because of the instability of the National Forestry Administration and the unrealistic nature of the management proposal. Japan's development assistance agency subsequently took over in the early 1980s, conducting further studies on natural and plantation forest regeneration, but this too failed to reach commercial proportions.

The forest area in question has always been disturbed, either by illegal logging or subsistence farming, the latter often condoned by the authorities. What remains is a fragmented, logged-over and despoiled forest, situated among a growing rural population with ever sharper sights on it as their next livelihood option.

Now, with financial assistance from the International Tropical Timber Organization (ITTO and the Government of Peru, the Project for the Management of Alexander von Humboldt National Forest has been asked to bring a total of 138 000 ha under sustainable management; 105 000 ha (75 percent) for timber production and 33 800 ha (25 percent) for wildlife refuge, seed production, conservation of genetic diversity and, in some cases, soil and water conservation (Table 1). The workload is enormous and the challenge truly daunting.

The establishment of growth plots and the permanent identification of trees are invaluable tools for evaluating the Impact of operations and calculating future harvests

Management priorities

The silvicultural model

There are indications that, when not more than 50 percent of the total basal area is harvested, selective felling produces an acceptable rate of natural regeneration for most species of interest. Additionally, profitability rises when 30 to 50 m³ per hectare are logged.

The intention is to harvest 3 500 ha per year over a 30-year felling cycle. The species have been classified into four groups according to commercial value (Table 2). The work will focus on 90 of these, classified according to whether they have a current or potential commercial value.

Forest inventory samples, taken at an intensity of 1.4 percent over an area of 13 000 ha, indicate a potential harvest volume of 30 m³ per hectare of timber with a current commercial value or 45 m³ if species with a potential commercial value are included. Nine I ha growth plots (0.25 percent of the targeted area) have been marked out for the first annual management unit (AMU 1), which is divided into three forest grades according to basal area. These growth plots will be measured every five years to assess forest growth and estimate future progress and output.

The first thinning will take place between years 3 and 5 after logging, with the second and last thinning taking place in year 10 to stimulate regeneration and growth of the 90 species selected. An average of 15 saplings of I m in height will also be planted, bare-rooted, on each hectare of logged-over forest. The following four species were chosen for their high commercial value: Mexican mahogany (Swietenia macrophylla), amburana (Amburana cearensis), Aspidosperma macrophylla and Cedrelinga catenaeformis. The objective is to harvest at least one high-value tree per hectare in the future managed forest, which would thus be better endowed than the original old-growth forest.

A projected average of 30 remaining trees per hectare will form the stock for the next felling cycle. A sample survey of 60 ha indicates standing volumes of between seven and 52 trees per hectare, depending on forest grade.

The management model

The idea is to auction the standing timber formally on logging plots of 200 to 400 ha. These can be acquired by any national or foreign individual or corporate body, who thereby acquires the right to harvest the timber within a two-year period. The standing timber price will be based on local market prices, including government taxes on the sale of trees in their natural state, i.e. without any form of improvement, and trees for reforestation.

Benefits provided through the project include the inventory and marking of all commercial trees, logging plot demarcation, the building and maintenance of primary forest roads, plans for access roads and timber yards, technical advice and training in rational harvesting and monitoring of the managed areas.

The income from the sale of the standing timber is expected to enable the project to cover its operating costs and be permanently self-sufficient. At present rates, in 1995 the sale of 70000 m³ of timber would generate an income of US$700 000, which is more or less the total expenditure so far incurred, including the contributions of ITTO and the Government of Peru. This balance at the start of management activities is considered a good sign, as reduced project costs and a higher income are expected in the next two to three years.

Income could be raised in a number of ways, including the introduction on the market of relatively unknown species such as the sapote Matisia cordata, a common medium-density white wood which has an average harvestable volume of 5 m³ per hectare. The manufacture of charcoal is also envisaged. mainly from felling debris. Charcoal has a guaranteed market and will involve the local population, which is a positive project spin-off.

TABLE 1. Administrative division and management sequence


Productive forest

Protection forest

Annual management unit

Total (ha)

Alto Macuya

14 000

6 750

Years 1-4

20 750

Alto Shebonya



Years 5-10

30 286




Years 11-14



28 000

4 835

Years 15-22


Aguaytía-San Alejandro

28 000

6 204

Years 23-30

34 204


105 000

33 800


138 800

TABLE 2. Targeted species

Commercial value








Not known




Other sources of income are under examination, including the sale of logs and sawnwood, the marketing of non-wood products such as "uña de gato" (Uncaria tomentosa) and palm heart, fibres (Dendrocalamus spp.) and tourism development.

Institutional framework

From the third year at the very latest, a start must be made on converting the project into a private entity capable of managing the forest development operation along corporate lines so that the income from the timber can be used to establish a Forest Management Fund for reinvestment in forestry activities, the goal being sustainability. This would be in line with the new juridical framework for state entrepreneurial activity whereby production is to be left entirely to the private sector, with the state confined to a promotional and regulatory role.


Tropical forest management should look beyond the short-term goal of maximizing forest biomass growth for timber output and make sure that the forest is able to play its fundamental ecological role.

The greatest obstacles to successful forestry development are not technical but rather social, political and economic. These include rapid population growth, limited employment opportunities and the reluctance of political leaders to opt for the long term, despite the fact that seriously sustainable forest management leaves no alternative.

Tropical forest development and management projects need to be more realistic economically and socially and must retrain from holding rosy expectations based on unrealistic assumptions.

The market for tropical timber is extending to hardwoods such as ana caspi (Apuleia leiocarpa) which could contribute substantially to economic sustainability

The monitoring of trees remaining in logged-over areas helps determine future harvests


Faber-Langendoen, D. 1992. Ecological constraints on rain forest management at Bajo Calima, Western Colombia. Forest Ecol. Manage., 53: 212-244.

FAO. 1993. The challenge of sustainable forest management. What future for the world's forests? Rome.

Sabogal, C. 1987. Struktur und Entwicklungsdynamik eines Amazonischen Naturwaldes bei Pucallpa, Peru. University of Göttingen, Germany. (thesis)

Silva, J.N.M. 1989. The behaviour of tropical rain forest of the Brazilian Amazon after logging. University of Oxford, UK. (thesis)

Unesco/UNEP/FAO. 1980. Ecosistemas de los bosques tropicales. Paris.

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