NaFORRI – National Forestry Resources Research Institute

This work is an INBAR publication produced as part of the Dutch-Sino East Africa Bamboo Development Programme—Phase II funded by the Ministry of Foreign Affairs of the Kingdom of the Netherlands and the National Forestry and Grassland Administration, China. The Dutch-Sino East Africa Bamboo Development Programme is a Triangular South–South cooperation to support livelihood development, food security, and better environmental management by developing robust bamboo value chains and a sustainable bamboo industry in Ethiopia, Kenya, and Uganda.

Bamboo_site_species_matching_study_in_Ug

Tree pruning is an important tree management option for reducing shading effects and altering whole-tree water use in smallholder farming systems. In this study, sap flow meters (SFM1s) were used to monitor whole- tree water use in Cordia africana (Cordia), Albizia coriaria (Albizia) and Coffea arabica (coffee) trees in two farms in Eastern Uganda.

Overstory trees were subjected to a 50% pruning regime at a 6-month interval over a period of 20 months (July 2018–February 2020). Analysis of variance General Linear Model was performed to assess the influence of tree species, management, season and their interaction on mean daily sap flow.

Pairwise Pearson correlation coefficients between daily sap flow and leaf phenology were also obtained. Pruning altered the synchrony in the vegetative phenology of Albizia trees, as leaf cover changes occurred earlier in pruned trees than in unpruned trees.

Pruned Cordia and Albizia trees respectively used 22.8% and 50.1% less water than unpruned trees whose average daily water use was 76.5L day⁻¹ and 133.7L day⁻¹ respectively. Episodes of reverse flows were observed in Albizia trees (pruned and unpruned) and the pruned Cordia during certain periods of the year. There was a statistically significant main effect of tree species, pruning, season and their interaction on daily tree water use (P < 0.05).

Coffee used 0.1 to 4.3 L of water per day over the 20-month period. While unshaded coffee used more water than shaded coffee, coffee growing under pruned trees used more water than coffee under unpruned trees. This could have resulted from more transpiration pull in coffee resulting from increased radiation with reduced shading.

Subsequently, canopy pruning reduced the water demand of the tree component and resulted in recharge in the crop-rooting zone, although this seemed to appear later following consistent pruning. The study findings demonstrate that agroforestry tree canopy pruning can regulate water use in smallholder agroforestry systems, the benefits of other tree products notwithstanding.

In a bid to curb deforestation and mitigate climate change effects, NaFORRI has developed technologies that improve wood recovery through efficient wood waste utilization. Various products have thus been developed from wood waste such as fuel lighters from saw dust and glulam furniture from timber offcuts.

NaFORRI has conducted research on renewable energy technologies geared towards reducing deforestation. Some of the products generated include energy saving cook stoves, charcoal and briquettes from wood waste and biodiesel from selected energy crops.

NaFORRI is also exploring the potential of various bamboo species for the furniture, construction and energy industry as well as for forest restoration and mitigation of climate change effects. This is premised on the fact that bamboo is a fast-growing plant and that bamboo species have physical and mechanical qualities comparable to those of woody species. Hence, various products have been produced including bamboo fuel, assorted kitchen ware and other artisan furniture.

NaFORRI’s successful intervention of using biological agents to control tree pests and diseases has given hope to hundreds of commercial Eucalyptus farmers who were losing their trees and livelihood. The invasion of exotic pests on the commercial tree growing scene in 2014, created uncertainty for tree growers. Before intervention, the devastating pests such as blue gum chalcid, Red gum Lerp psyllid and Bronze bug were wiping out Eucalyptus trees in Uganda estimated at 50,000 ha, and pausing a likely loss of 1.75 trillion shillings in revenue.