Influence of smallholder woodlot management to tree growth and tree quality

Abstract

Smallholder tree plantations possess a substantial capacity to produce sustainable timber material, while providing additional income to farmers. This thesis studies the effects of forest management practices to tree growth and tree quality in smallholder pine woodlots in Tanzania. The analysed data consists of woodlot inventory measurements and farmer interviews from four villages in Njombe region. Additionally, key-informant interviews were conducted with relevant stakeholders to briefly explore the timber value-chain of the region.

The results indicated that variety of factors affect to the conditions of the smallholder woodlots in the case study area. The main finding was that implemented forest management practices had varying and complex effect on both, tree growth and quality. While some of the practices were observed to be associated with better growth performance, some were also observed to have a negative effect on growth. However, large variety persisted between these effects. This indicates that it is of high importance how practices are done, rather than what sort of individual practices are implemented. Similar observations were made regarding the connection between tree quality, which was assessed by rate of various defects in trees. Alarmingly, the amount of implemented practices was observed to generally increase the share of trees with severe defects. This further highlights the importance of the quality of forest management.

Furthermore, the effect of seed and seedling origin to tree growth and quality was analyzed. There was clear improvement in growth with stand established from seedling acquired from private or governmental nurseries, compared to seedlings grown by farmers themselves. This relates to seed origin, as in nurseries the seedlings are generally grown from seeds of controlled breeding programmes, whereas the farmers normally collect the seeds where they can find them. However, seed or seedling origin did not have any major effect on the rate of observed defects, indicating that the forest management practices together with unmeasured site characteristics play a dominant role here.

The key findings of this thesis highlight the importance of market demand for timber, as in long-term, the tree plantations are only managed productively when there are markets where the timber can be sold. In the case study area, the market demand was high, and in some ways, even too high, as even poor quality trees were generally sold easily, though at reduced price. This is a result of limited governmental forest plantation resources failing to meet the growing domestic demand for sawn timber. Too high demand may cause an incentive not to invest in improvement of plantation performance, and therefore prevent development of the whole processing-chain. One solution to this would be introducing adequate quality-based timber pricing system. If correctly done, this would create appropriate incentive for smallholders to invest in their tree plantation management to be able to receive price premiums for good quality trees. However, many obstacles remain. For example, bad accessibility to smallholder woodlots is preventing cost-effective transportation of roundwood to be processed in stationary sawmills with improved sawing machinery.

As a general conclusion, there is substantial potential in smallholder tree plantations to provide timber to growing global demand. However, in large parts, this potential is still un-tapped, and significant support efforts are needed to be able to provide good quality material and to access production of value-added products for domestic and export markets. Nevertheless, in Tanzania smallholder tree plantations are already providing timber to domestic markets, and the importance is only increasing as other sources fail to meet to the ever-growing demand. If adequate amount of land is available, and farmers have equal possibilities to participate, smallholder tree growing can provide sustainable source of timber, while also contributing to the improvement of rural livelihoods.