Questions: Is multi-stemming a survival strategy in response to chronic disturbance? Is multi-stemming under phylogenetic control? What environmental factors are associated with multistemming? When do trees initiate growth of multiple stems? Do multi-stemmed trees have limited stature? Location: Subtropical Indian Ocean coastal dune forest at Cape Vidal in the Greater St. Lucia Wetland Park, northeastern South Africa. Methods: Tree physiognomy and environmental conditions were sampled in 20 transects that were 300 m long and 5 m wide. Results: 38.9 % of trees were multi-stemmed, with no correlation between multi-stemming and taxonomic grouping. The multi-stemming trait was most associated with stem decumbency and substrate erosion and multi-stemmed individuals were less common in protected dune slacks. Trees at Cape Vidal appear to facultatively produce multiple stems from an early stage. There was no trade-off between tree height and stem number. Conclusions: Coastal winds and the unstable dune substrate are important environmental correlates of multi-stemming. Both short stature and the high incidence of multi-stemming are related to the tree-disturbance interaction. The taxonomically widespread phenotypic plasticity in this trait indicates the importance of multi-stemming to tree survival even under low levels of disturbance. Nomenclature: Coates Palgrave (2002).Abbreviations: AIC = Akaikeʼs information criterion; AN-COVA = Analysis of covariance; ANOVA = Analysis of variance; CV = Coefficient of variation; DBH = Diameter at breast height; GLM = Generalised linear model; IV = Importance value; PCA = Principal components analysis.

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Summary 1.Resprouting in woody plants is a trait that facilitates persistence in disturbance-prone environments. Patterns of allocation of resources for resprouting may depend on the severity of disturbance to which the plants are adapted. Fire-adapted plants allocate more resources to below-ground structures for resprouting after destruction of above-ground structures. However, plants that resprout in response to disturbances where above-ground structures survive may remobilize above-ground resources for resprouting. 2. In coastal sand dunes, stem leaning and partial uprooting of trees result in high frequency of resprouting (38·9% of individuals; 90·6% of species). We tested whether 'good' and 'poor' resprouters differed in allocation to root biomass and root carbohydrate reserves. Species were assigned to categories of resprouting ability based on the frequency of multi-stemmed individuals in the local population. To control for phylogenetic effects, we contrasted poor and good resprouter species pairs from three families. 3. We tested whether plants stored more reserves in roots or stems and whether above-ground resources were remobilized for resprouting. The latter was measured from the number and dry mass of sprouts produced by trees cut to stump heights of 10 and 150 cm above-ground level. 4. Good resprouters had larger seedling root:shoot ratios and higher stem and root carbohydrate concentrations than poor resprouters. Both good and poor resprouters maintained higher carbohydrate concentrations in stems than in roots. 5. For both good and poor resprouters, 150-cm stumps produced more sprouts than 10-cm stumps. At each stump height, good resprouters produced more sprouts than poor resprouters. 6. Resource allocation in coastal dune trees appears to be a bet-hedging strategy. After low-severity disturbances, resprouting occurs by remobilization of above-ground resources. Below-ground resources may be more costly to remobilize but may allow recovery from occasional more severe disturbances.

To survive, leaning trees on steep slopes with loose substrate can either resprout or turn upward to regain the normal vertical orientation of the growing tip. Data from 19 tree species were collected from 20 transects in coastal dune forest. Resprouting was negatively correlated with turning up and species abundance, and positively correlated with leaning and a dead primary stem. In contrast, turning up was associated with low probabilities of leaning and higher species abundance but not with a dead primary stem. Slightly inclined trees turned upwards more than severely inclined ones, which mostly resprouted. Leaning trees without exposed roots turned upwards, while severe erosion caused leaning and resprouting. Consistent with the latter, leaning trees in stable dune slacks frequently turned upwards, whereas leaning trees on narrow dune crests and steep landward slopes seldom did so. Small trees were more likely to turn upwards than big trees. Because of potentially greater costs to the individual of sprouting, stem reorientation precedes the resprouting response across the disturbance gradient. Consequently, species prone to stem reorientation and less likely to resprout, are dominant during late-succession. This study emphasizes the advantage under low levels of disturbance of turning up as an alternative strategy to resprouting for leaning trees.

Miombo woodlands are major vegetation type covering about 93% of the forest land of Mainland Tanzania. It forms an integral part of the rural landscape in Tanzania and plays a crucial role in providing a wide range of goods and services including carbon sequestration. However, the sustainability of forest resources is mostly affected by the magnitude of its utilization. There should be a balance between the forest growth and removals. Nevertheless, the magnitude of removed volume and carbon in the country is not known. Quantification of volume, biomass, and carbon stocks removals is vital in developing effective climate change mitigation strategies, decision making, and promoting sustainable forest management. Based on the National Forest Resources Monitoring and Assessment data (NAFORMA) comprising 7,026 stumps collected from 16,803 circular plots of 10 m and 15 m radii established in Miombo woodlands of Mainland Tanzania, volume and carbon stock removals were estimated with the use of models that utilize stump diameter (SD) as the sole predictor. Results indicate that the annual volumes, aboveground biomass removed, and belowground biomass removed were 1.71 ± 0.54 m3 ha−1 year−1, 1.23 ± 0.37 t ha−1 year−1, and 0.43 ± 0.12 t ha−1 year−1, respectively. In addition, the corresponding aboveground and belowground carbon removed were found to be 0.6 ± 0.18 tC ha−1 year−1 and 0.21 ± 0.05 tC ha−1 year −1 respectively. Since the estimated annual volume removals exceed estimated mean annual increment of 1.6 ± 0.2 m3 ha−1 year−1 in Miombo woodlands, the removals indicate unsustainability that would end up into forest degradation. The results also show that removals are more prominent in the following categories: shifting cultivation, production forest, grazing land, general land, village land, and Eastern and Southern zones. This paper calls for increased appropriate management strategies to ensure sustainability in these land categories and in the entire Miombo woodlands of Mainland Tanzania.