Abstract

This thesis summarises results o f four articles concerning the woody growth, in particular with reference to potential fuelwood, in savanna woodlands in the North Sudanian Zone. Three studies concern the woody sprouting 5-14 years after clear-cutting on five sites protected from grazing and fire. The fourth article concerns the impact of livestock exclosure and different fire regimes on woody sprouting six years after selective cutting.

In the clear-cutting experiments there were on average 858 stools ha'1 with 2.3 stems >10 cm gbh (girth at breast height) per stool with a mean height o f 4 m. Basal area at 130 cm was 3.9 m2 ha'1 and this was 60 % o f the basal area at 20 cm.

Average stem height growth was 33 cm yr1 and basal area growth was 0.31 m2 ha'1 y r1. Dry biomass growth was 1.1 Mg ha'1 y r 1 corresponding to 1.7 m3 ha'1 y r1. Trunks, branches and stemlets made up about a third each of the total woody yield. One third of the trunk was bark. Thus, the actual trunk wood production was about a third of the total production or on average 0.40 Mg h a 1 y r 1 corresponding to 0.59 m3ha'‘ y r1. Excluding species less suitable for fuelwood about a fourth of total yield remained. Average ratio of dry mass to green volume was 0.67 Mg m '\ Species basic density ranged from 0.30 to 0.85 Mg m'3 and bark proportion ranged from 9 % to 53 %. Each site was dominated by some few species specific for each site.

Results from the fourth article indicate that livestock exclosure decreased stump survival and sprout growth, most likely due to grass competition. Six years after cutting 20 % of the basal area cut at stump height had been restored.

Keywords

dry forest; semiarid; yield; production; bark; wood; indigenous species; basic density; growth; coppice; secondary succession; regrowth; fuelwood

Published in

Acta Universitatis Agriculturae Sueciae. Silvestria
2000, number: 144
ISBN: 91-576-5878-1
Publisher: Department of Silviculture, Swedish University of Agricultural Sciences

SLU Authors

• Nygård, Robert

  • Department of Silviculture, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/107950