Our study focused on the effects of wood poaching on the vegetation structure and composition in Mukuvisi Woodland, Zimbabwe. Mukuvisi Woodland, located within the precincts of Harare urban area, Zimbabwe, suffers from high illegal wood utilization pressure stemming from the need to fulfill alternative energy demands created by persistent electricity shortages and an unstable economic environment, particularly between 2000 and 2008. This results in a continuous flux of vegetation and a disturbed animal habitat driven mainly by anthropogenic activities. Due to the heterogeneity in vegetation utilisation trends, we used the stratified systematic random sampling technique, where the site was divided into two strata, central and boundary. Twelve 30 × 20 m permanent plots were established in which species name, species diversity, height, basal area, plant status, fire evidence, number of stems and saplings were recorded and assessed in April and May 2012. A total of 968 woody plants were assessed representing 47 woody plant species. All woody vegetation variables recorded and assessed showed no significant difference (P > 0.05) between the two strata, i.e., central and boundary, in Mukuvisi Woodland, except sapling density (P = 0.022). Principal Component Analysis indicated evidence of fire impacts on vegetation structure. The study concludes that illegal wood harvesting in Mukuvisi Woodland has not yet reached alarming proportions and can be contained. The study recommends collaborative arrangements with key stakeholders, promotion of the use of alternative energy sources and increased environmental education and awareness campaigns.
At a national scale, Comiskey and Sunderland [
Wood poaching is regarded as a threat to protected area woodland in close proximity to human habitations [
Mukuvisi Woodland, located at latitude 17˚50'35S and longitude 31˚5'42E, covers approximately 274 hectors [
Annual rainfall ranges between 650 - 850 mm recorded between November and March and summer temperatures range between 16˚C and 30˚C [
The study area was stratified into two study strata, namely the central area and the park boundary. Sample plots were randomly placed based on Mukuvisi Woodland topographical map using grid intercept method across the defined two study strata. A total of 12 sample plots were sampled between April and May 2012. Four plots were 100 m from the boundary and the remaining 8 were located 5 km from the boundary and were in the central area of Mukuvisi Woodland. Sampling plots measuring 30 × 20 m were delineated on each of the strata. Woody species occurring within a sample plot were identified using field identification guides [
Data were tested for normality using KolmogorovSmirnov test in STATISTICA version 6 for Windows [
cluster composition across the strata [
A total of 117 woody stumps were recorded, mostly close to the boundary, translating to about 12.1% of poached woody trees across the strata.
As indicated by the prevalence of recorded stumps, J. globiflora (69%) and B. speciformis (23%) had high tree stumps, showing that they were the most preferred and harvested while species like Vangueria infausta, Protea roupelliae roupelliae, Combretum molle and Newtonia hildebrandtii, were not only less common, but also least preferred with each accounting for less than two percent of stumps recorded.
A total of 968 woody plants, representing 47 woody species were recorded in the 12 sample plots. The dominant woody species recorded include J. globiflora, B. speciformis, B. boehmii and Parinari curatellifolia. All the measured or recorded woody vegetation variables indicated no significance difference (P > 0.05) between the strata (
The Principal Component Analysis of the woody vegetation variables showed a variance of 34% (eigenvalue = 3.4) on Factor 1 and 23% (eigenvalue = 2.3) on Factor 2 in the woody species composition and structure (
The Hierarchical cluster analysis (HCA) using the Ward’s method with Euclidian distances showed that there are 47 species in abundance data in the study sites. We noted two sub clusters A and B. Sub cluster A, sample plot B4 and C8 show a slight variability in species
composition compared to the sample plots B1, B2 and B3. In sub cluster B, sample plots C1, C2, C3, C5 and C7 show little variability in terms of species composition (
Our results showed that woody vegetation composition of the conserved Mukuvisi Woodland area was dominated by J. globiflora, B. spiciformis and B. boehmii, specifically resembling the Miombo woodlands of southern African savanna [26-29]. Regardless of the high representation of J. globiflora and B. speciformis and many other endemic woody plants at local or regional scale, these Miombo woody species are threatened by anthropogenic activities especially wood poaching as recorded in this study and this could be attributed to their hardwood type preferred for fuel wood, poles, construction and carpentry [
Our study results showed that fire damage was negatively correlated to tree size (tree height and basal area) and sapling density, whereas, fire damage was positively correlated to dead plant density (
There were no significant differences among all assessed variables across the strata except sapling density. This indicates that wood poaching between the strata are not yet pronounced. Significant difference in sapling density
between the central and boundary strata may explain the higher impact of fire damage rather than wood poaching in the central area. The most observed trend is that human disturbed vegetation is characterised by high sapling density.
For woody species of slow growth rate, recruitment is interpreted as viable when woody species have a larger proportion of saplings than larger trees, and recruitment is considered poor when there are larger proportions of trees than saplings [38-40]. On the basis of this indicator, our study results of high proportion of tree density as compared to saplings could suggest less vibrant recruitment of woody species in Mukuvisi Woodland. There was evidence of large tree extraction on Mukuvisi Woodland as represented by relatively low tree densities, high number of stumps and high dead plant density. Wood poaching is known to affect micro-sites for plant establishment and the resultant woody plant diversity and density [41,42], this could be a contributing factor to relatively low woody species diversity and high dead wood density in Mukuvisi Woodland. Consistent with observations by Fadiman [
The dominant tree species in Mukuvisi Woodland, J. globiflora and B. spiciformis are highly targeted by wood poachers. We conclude that there is moderate to high levels of woody poaching as indicated by the cut trees and also sapling density that was relatively high. Moreover, woody poaching was more evident close to the boundary of the Mukuvisi Woodland than the inner areas. However, our results suggest that there is slight modification of the woody vegetation in Mukuvisi Woodland, especially the structural component. Therefore, we recommend increased law enforcement and conservation awareness education to reduce woody species poaching. Consistent with other authors like Du Plessis [
The authors extend their appreciation to Mukuvisi Woodland management for allowing this study to be carried out in their property. We also acknowledge staff in the Department of Wildlife and Safari Management at Chinhoyi University of Technology for their support and constructive criticism.