Closed Canopy Woodland Research Articles

Effects of ice storm-created gaps on forest breeding bird communities in central Vermont

A damaging ice storm struck northern New England, NY, and adjacent Canada in January 1998, affecting nearly 7 million ha of forest lands. Although relatively rare at this scale, such natural disturbances provide a unique opportunity to study short- and long-term impacts on forest ecosystems and wildlife species. I investigated the storm’s short-term effects on breeding birds in a northern hardwood forest in central Vermont. Point counts ( n=52) at six ice-damaged study sites in the Green Mountain National Forest were used to compare post-storm bird abundance with pre-storm samples collected at the same points in 1993 or 1994, and at five control sites ( n=25) that were unaffected by the storm. In general, damage to canopy trees consisted of broken limbs and main stems, with lesser amounts of uprooted trees. This resulted in perforations, or small forest gaps. Overall, species richness and diversity increased only at ice storm sites, whereas total abundance increased at controls. Three forest-interior species declined in abundance ( P≤0.046) following the storm, two canopy-foragers (Red-eyed Vireo and Blackburnian Warbler), and a ground-forager/nester normally associated with closed-canopy woodlands (Ovenbird). Another ground-forager/nester, Dark-eyed Junco, was the only species to increase in abundance ( P=0.046) after the storm, although Winter Wren showed a marginal increase ( P=0.075). Among habitat/foraging guilds, two forest-interior groups (canopy-foragers and ground/shrub foragers) declined significantly ( P≤0.034), whereas open-edge ground/shrub feeders increased marginally ( P=0.069). Results from this study are consistent with investigations of bird responses to selective forest management, particularly “group selection” and “single-tree selection”, suggesting that these management strategies may effectively emulate natural disturbance events such as ice storms.

Food and density limitations of the Seychelles Magpie Robin, Copsychus sechellarum, on Cousine Island

The critically endangered Seychelles Magpie Robin, Copsychus sechellarum, is one of the rarest birds in the world. At the end of December 1999, there were 88 individuals distributed on four small granite islands: Fregate, Aride, Cousin and Cousine. Little is known of Magpie Robin ecology in its natural habitat. Studies carried out on Aride, Cousin and Cousine are therefore valuable as each island is dominated by native woodland. The composition of Magpie Robin diet was compared between Fregate and Cousine. An exotic species of cockroach, Pycnoscelus indicus, and dropped fish were found to be considerably more important prey items on Cousine. Observations of chick food provisioning indicated habitat quality differences between the territories. Invertebrate and vertebrate food resources available to the Magpie Robin were sampled on Cousine between 1997 and 1998. Fourteen sites were sampled for invertebrates and fifty-two species from fifteen taxa were identified. There were significant differences between the mean number of species recorded per site and the mean number of animals found at each site. Skink density was estimated at between 1219-1516/ha and 354-538/ha for Mabuya sechellensis and Mabuya wrightii respectively. Invertebrate diversity and abundance was greatest in areas dominated by closed-canopy woodland on or near the coastal plain. These results explained the current distribution of Magpie Robin territories. The invertebrate abundance data were used to estimate the carrying capacity of the island for the Magpie Robin. Cousine could theoretically support up to six breeding pairs but it is questionable that a population of this size could be self-sustaining in the long-term.

Caracterização fitofisionômica e levantamento florístico preliminar no Pantanal dos Rios Mortes-Araguaia, Cocalinho, Mato Grosso, Brasil

O presente estudo realizou-se no Pantanal dos Rios Mortes-Araguaia, extensa planície inundável localizada no municípo de Cocalinho, nordeste de Mato Grosso, Brasil. Efetuou-se uma caracterização fitofisionômica e um levantamento florístico preliminar da região. Foram selecionados três Sítios, com fitofisionomias representativas: proximidades do Rio das Mortes (12° 37'S; 50° 55'W), foz do Rio das Mortes com o Araguaia (11° 54'S; 50° 48'W) e porção mediana do Rio Cristalino (12° 52'S; 50° 49'W). O método de amostragem adotado foi o de levantamentos rápidos. Foram identificadas oito fitofisionomias: Mata Inundável, Caapão, Babaçual, Cerradão, Cerrado stricto sensu, Campo de Murunduns, Campo de Byrsonima orbignyana e Campo Cerrado de Vochysia rufa. Foram levantadas 248 espécies de árvores, arbustos, sub-arbustos e lianas, distribuídas em 158 gêneros e 62 famílias. As fitofisionomias apresentaram um padrão heterogêneo, sendo que nenhuma das espécies ocorreu em todas elas. Porém, Alibertia edulis (L. Rich.) A. Rich., Andira cuyabensis Benth., Maprounea guianensis (Aubl.) M. Arg., entre outras, ocorreram em seis das oito fitofisionomias. As famílias com maior riqueza foram: Caesalpiniaceae, Annonaceae e Myrtaceae. Ocorreram algumas semelhanças florísticas com o Pantanal do Rio Paraguai, porém, são necessários estudos mais aprofundados para confirmar. Os padrões de heterogeneidade fitofisionômica indicam que a área estudada necessita de medidas conservacionistas.

The spatial distribution of beetles within the canopies of oak trees in Richmond Park, U.K.

Summary1. 5054 adult beetles of 144 species were collected in a total of 696 1‐m2 collecting trays by knockdown insecticide fogging of 36 different oak trees in closed canopy woodland at Richmond Park, U.K., with three of the trees sampled on each of 12 dates, at 2‐ to 3‐week intervals, between April and October 1984.2. In late spring (April/May), more individuals and species of beetles were collected in trays close to the trunks of trees than in trays more distant from the trunk. The reverse was the case in late September/October. Neither pattern prevailed in the intervening months.3. Individual species exhibited a variety of patterns, with some species more abundant near the trunk, e.g. Leiopus nebulosus (L.), Strophosoma melanogrammum (Forster), Cylindronotus laevioctostriatus (Goeze), and Dromius agilis (Fabricius), and some less abundant near the trunk, e.g. Curculio pyrrhoceras (Marsham) and Rhynchaenus signifer (Creutzer). For Adalia decempunctata (L.), this preference changed with season. The observed species preferences for parts of a tree crown near or distant from the main trunk are discussed with reference to their known biologies.4. No pronounced pattern of preference for north‐ or south‐facing aspects of trees in closed canopy woodland was observed, however populations of some species exhibited patterns of within‐tree distribution that correlate with compass angle; for one species, the ladybird Adalia decempunctata, this distribution changed with season and between colour morphs.

Habitat selection and foraging success of Hen Harriers Circus cyaneus in west Scotland

The foraging behaviour of Hen Harriers breeding in west Scotland was studied in a variety of afforested and moorland habitats. Time budget information from sample areas, stratified by habitat type and controlled for nest distance, was used to investigate habitat selection. Preferences were then related to measures of foraging performance in each habitat. Hen Harriers foraged preferentially over young first rotation coniferous forests, and selected heathland and grassland habitats ahead of closed canopy woodland. Harrier preference for the various habitats was positively correlated with the frequency with which they struck at, and captured, prey. Prey strike success was much lower than that reported for moorland managed for Red Grouse Lagopus lagopus scoticus. The results explain many of the reported changes in local Hen Harrier populations. The extent of young first rotation forestry is currently in decline. It is predicted that this will lead to a reduction in numbers of Hen Harriers breeding in west Scotland, and an increase in the proportion of the British harrier population occupying moorland managed for Red Grouse.

Retention of reproductive barriers and ecological differences between two introduced sympatric Macropus spp. in New Zealand

In their native Australia, tammar (Macropus eugenii) and parma (M. parma) wallabies are allopatric and differ markedly in habitat use, social structure and degree of reproductive synchrony. They occur sympatrically only on Kawau Is., New Zealand, as a result of introductions last century. Reproductive data collected from wallabies on Kawau Is. in April 1996 show that M. eugenii maintains high reproductive synchrony while M. parma remains asynchronous. Both species show sexual dimorphism and differences in habitat use as seen in Australia. In addition M. parma is more solitary, and is frequently found in closed-canopy woodland, while M. eugenii tends to aggregate in open grassy clearings. Thus the species maintain broad reproductive and biological distinctions, despite enforced sympatry in a novel environment. Highly-resolving genetic (microsatellite) data reveal no evidence for hybridization. This is essential information given the known (M. eugenii) or likely (M. parma) high conservation value of New Zealand stocks. Kawau Is. is the only predator-free site with M. parma, a species whose persistence in Australia is threatened by fox predation. Finally, we use data on mitochondrial cytochrome b sequence divergence amongst several Macropus taxa to demonstrate close agreement with degree of reproductive isolation.

Patterns of vegetation along the Omo River in southwest Ethiopia

This study investigates the riverine vegetation along the perennial Omo River, which flows from the Ethiopian highlands to its terminus, in the southwestern lowlands, at Lake Turkana (formerly Lake Rudolf). Broadly defined to include the levee backslopes and adjacent mudflats (or ancient floodplains), the riverine zone in the lower Omo basin supports a relatively luxuriant vegetation compared with the dry grasslands in the surrounding plains environments. Habitat conditions along the lower Omo have changed significantly during the past century, primarily due to a period of reduced rainfall and river flow, a drop in lake level (L. Turkana) at the river's terminus and increased exposure of natural levees near the Omo's terminus. The floristic and physiognomic character of riverine vegetation were studied at selected sites, ranging from the relatively straight channel section in the modern delta to a strongly meandering (upstream) section of the river. A combination of open canopy woodland, shrub thicket and grassland (with scattered tree emergents) prevailed on the more recently exposed levees, in and near the modern delta; closed canopy woodland and forest predominated on fore levees in the meandering segment. Floristic diversity was relatively low at all study sites. Ficus sycomorus, Tapura fischeri, Melanodiscus oblongus, Celtis integrifolia and Trichilia roka were most significant in upstream forest sites, whereas Cordia sinensis, Acacia mellifera, Ziziphus mauritiana and Ficus sycomorus were more common in communities nearer the lake. Older forests generally contained greater diversity of more woody species, greater tree height and truck diameter than downstream levee vegetation, but they did not exhibit clear stratification. Species patchiness was broadly characteristic of the riverine zone, particularly the mudflats (ancient floodplains) extending away from the fore levees. Fires are frequently set by local inhabitants throughout the grasslands of the lower Omo Basin; within the riverine zone, they are particularly common in the mudflats but have only limited impact on woodland and forest vegetation. It is suggested that fire is a highly significant factor in the establishment of sharp boundaries between the closed canopy woodland/forest along the river and the more xerophytic vegetation of the mudflats.

Abundance and diversity of soil macrofauna in northern Botswana

ABSTRACTThe abundance and diversity of soil macrofauna were assessed in a range of vegetation types in northern Botswana. Hand-sorting of soil was used to extract all fauna greater than 2 mm body length from sandy soils in both the dry season (June) and towards the end of the single rainy season (February). Abundance varied significantly between samples from within a sampling location, within a vegetation type and occasionally between seasons. Greater densities were found in wet season samples from locations within closed canopy woodland except where permanent water was a significant feature of the habitat. Overall abundance was comparable to published estimates from more moist tropical and temperate habitats suggesting an important role for soil macrofauna in semi-arid systems. Ordinal level diversity also varied significantly within vegetation types and with season.

Redberry Juniper-Herbaceous Understory Interactions

Basal cover, density, biomass, and species richness of the understory were measured in concentric zones from the stem bases of large redberry juniper (Juniperus pinchotii Sudw.) trees to 6 m beyond their canopy edges on a shallow, rocky soil and 2 deep soils in the northern Edwards Plateau of Texas. The juniper-driven successional processes of tree dominance, debilitation of understory dominants, influx of subsidiary species, and the general reduction in diversity, density, and biomass of the herbaceous species were evident on all 3 sites. Juniper interference intensified with increasing proximity to the stem bases. Biomass and basal cover of the herbaceous understory responded to a greater extent than did density and species richness 2 years after large redberry junipers were killed with soil injections of picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid). Herbaceous biomass responses after junipers were killed indicated that the sphere of influence of large junipers was more extensive on the shallow soil than on the deep soils. Herbaceous biomass in the presence of interference by large junipers on the Kimbrough, Angelo clay loam, and Tulia loam soils was 1,300, 1,780, and 1,290 kg ha-1, respectively, compared to 2,140, 2,140, and 1,560 kg ha-1 2 years after the junipers were killed on the 3 sites, respectively. Projected herbaceous biomass when juniper populations on the sites develop into closed-canopy woodlands was 320, 880, and 270 kg ha-1 for the Kimbrough, Angelo clay loam, and Tulia loam soils, respectively.

Herbicide Effects on Cross Timbers Breeding Birds

We censused breeding nongame birds on replicated 5- and 6-year post herbicide-treated (tebuthiuron and triclopyr) and untreated cross timbers rangeland in central Oklahoma. Twenty species of breeding birds were observed. No treatment effects were detected for total bird density, species diversity, or richness; however, species composition varied considerably among treatments. Control sites supported species associated with closed canopy woodlands, and treated sites supported species associated with brushy and prairie habitat. Generally, control sites had greater foliar cover, fewer snags, and less slash and herbaceous cover than treated sites. Densities of 6 of the 7 most abundant bird species were correlated variously with habitat variables. We concluded that changes in habitat structure resulted in differences in bird species composition among treatments.

Habitat Use by a Boid Snake, Epicrates monensis, and Its Anoline Prey, Anolis cristatellus

We quantified the habitat use of the endangered Virgin Islands boa (Epicrates monensis) and its prey (Anolis cristatellus) on Cayo Diablo, Puerto Rico. Although anoles occurred throughout the island, boas selectively foraged within groves of Coccoloba uvifera. Boas and anoles did not differ sig- nificantly in their plant species use within these groves. Adult male and adult female (>400 mm SVL) boas did not differ significantly for six measures of microhabitat use, but when juvenile snakes (s400 mm SVL) were included in the analysis, there was a significant correlation between boa SVL and foraging height. Adult male anoles occupied sleeping perches that were higher, of larger diameter, and farther out on branches than those of adult female and juvenile anoles. Principal components analysis revealed that anoles sleep on short, thin branches relative to those favored by foraging boas; adult male anoles occupy sleeping sites most similar in structure to those used by boas. We suggest that foraging by boas does affect habitat use of anoles, and that adult male anoles are constrained to sites similar to those used by boas by the need to hold territories or for high-quality thermal environments. Closed canopy woodland seems to be an important habitat requirement for the endangered E. monensis.

Modelling of Dispersion and Deposition of Tree Pollen within a Forest Canopy

Abstract The relative merits of applying contemporary atmospheric diffusional models to reconstructing Quaternary vegetational patterns via modern pollen rain studies are being examined in a continuing research project to model tree-pollen dispersion mathematically in closed-canopy woodlands, and to compare it with the traditional methods of Palynologists. It has been ascertained that the forcing functions required to drive the state-of-art dispersal equations are lacking in the palynological field, and thus limits to the usefulness of trying these are proposed. Finally, applications are suggested to other problems in palynology and present-day atmospheric diffusion.

Porcupines, Fires and the Dynamics of the Tree Layer of the Burkea Africana Savanna

(1) The tree layer of the Eragrostis pallens-Burkea africana savanna is composed primarily of Terminalia sericea and B. africana with other tree species occurring infrequently. Burkea africana is dominant on well drained soils at the upper portions of a soil catena, co-dominant with T. sericea at midslope and replaced on seasonally waterlogged soils at the base of the slope by T. sericea. (2) There is a successional process occurring within the tree layer. Terminalia sericea establishes only on open sites and never under itself or other members of the tree layer. Burkea africana establishes on open sites, under T. sericea and under itself. Dombeya rotundifolia, another common tree, establishes under B. africana but not under T. sericea or itself and never in the open. The other tree species establish either under the canopies of large individuals of B. africana or on termite mounds. (3) The general successional sequence is T. sericea followed by B. africana and later D. rotundifolia or other shade-tolerant tree species. The actual successional sequence varies over the slope. In the upper portions, where T. sericea is uncommon, B. africana initiates the sequence and is followed by more shade-tolerant species. At midslope, T. sericea generally establishes first, followed by B. africana and later by shade-tolerant species. At the base of the slope, T. sericea is dominant since it is able to withstand the seasonally waterlogged soils there. During long periods of drought B. africana may establish secondarily. Other tree species rarely establish in this zone and then usually upon termite mounds. (4) A mature, closed-canopy woodland does not develop due to the disturbance by porcupines and fire. Porcupines ringbark trees and expose the heartwood to fire. They preferentially attack D. rotundifolia and B. africana in that order and rarely scar T. sericea. The strong preference of porcupines for D. rotundifolia results in many coppiced shrubs and a reduction in the number of individuals reaching tree status. The secondary preference for B. africana, which is abundant over much of the slope, results in large individuals being removed by fire more frequently than T. sericea. Of the large, live trees that fell after a fire in September 1985, 57% were B. africana. (5) The Eragrostispallens-Burkea africana savanna is maintained by porcupines and fire as a mosaic of grassland and small woodland patches undergoing cyclical successions developing after the fall of large individuals of B. africana.

Autogenic Succession in a Subtropical Savanna: Conversion of Grassland to Thorn Woodland

Dense thorn woodlands occupy what are thought to have been grasslands and savannas prior to settlement of the Rio Grande Plains of Texas. However, the tenet that grasslands have been converted to shrublands and woodlands in recent history is controversial and based largely upon conflicting historical accounts. Our objective was to determine how the presumed physiognomic conversion from grassland or savanna to woodlands might have occurred. Some upland landscapes are dominated by closed—canopy woodlands in southern Texas, whereas others have a two—phase pattern of discrete shrub clusters scattered throughout a grassland. More mesic sites are dominated by losed—canopy woodlands. We hypothesized the two—phase landscapes represented an intermediate stage in the conversion of grassland to woodland. As new shrub clusters were initiated and existing clusters expanded and coalesced, a gradual shift from grassland to savanna to woodland would occur. To address this hypothesis, we inventoried herbaceous interspaces for woody colonizers, quantified the composition and distribution of shrub clusters on upland sites, and compared the structure of clusters to that of adjacent, more mesic areas with continuous woody plant cover. To assess the physiognomic stability of the two—phase landscapes, cluster size, density, and cover were quantified for 1941, 1960, and 1983 from aerial photographs. A lone mesquite (Prosopis glandulosa) plant occurred in >80% of the upland clusters, where it was typically the largest individual in terms of basal area, height, and canopy area. The number of woody species per cluster ranged from 1 to 15 and was strongly related to mesquite basal diameter (R2 = 0.86). Cluster diversity, evenness, and size were also significantly correlated with mesquite size. The data suggest that mesquite plants invaded grasslands and served as recruitment foci for bird—disseminated seeds of other woody species previously restricted to other habitats. The result was a landscape composed of discrete chronosequences of woody plant assemblages organized about a mesquite nucleus. Within the two—phase portion of the landscape, 50% of the clusters were within 5 m of another and 95% were within 15 m of another. Analysis of the size class distribution of clusters suggested that most had yet to realize their growth potential. Moreover, the herbaceous clearings between clusters contained high densities of woody seedlings, mostly (>70%) mesquite, which occurred in 85% of the clearings, with a mean density of 350 plants/ha. Coalescence will become increasingly probable if new clusters are initiated and existing clusters expand. This phenomenon appeared to be in progress on one portion of the landscape and had apparently already occurred on others. As clusters developed on the two—phase portion of the landscape, their species composition, dominance, and size class structure became increasingly similar to that of adjacent closed—canopy woodlands on more mesic. Mean cluster size increased from 494 m2 in 1941 to 717 m2 in 1983. Growth rates of clusters were a function of cluster size and precipitation. During the 1941—1960 period characterized by severe drought, there was a slight decrease in total woody plant cover resulting primarily from the formation of gaps among clusters on the periphery of the site and a 35% decrease in density of clusters <5 m2. These cover losses offset the areal expansion of small (<100 m2) clusters which had an average relative growth rate (RGR) of 0.10 m2 · m—2 · yr—1. Post—drought woody plant cover increased from 8% in 1960 to 36% in 1983 as new clusters were initiated density increased from 16 to 26 clusters/ha), and the RGR of small clusters increased to 0.16 m2 · m—2 · yr—1. Numerous clusters coalesced during this period. RGRs of clusters >100 m2 were an order of magnitude lower than those of clusters <100 m2 in each time period. The RGR of large clusters following the drought was not significantly increased, except in the largest size class (clusters >1,000 m2). Our results indicate (1) mesquite invaded grasslands and served as the nucleus of cluster organization on upland sites; (2) woody plant community development has been highly punctuated by variations in precipitation; (3) clusters >5 m2 in area are persistent features of the landscape; and (4) the present two—phase pattern is moving toward a monophasic woodland as new clusters are initiated and existing clusters expand and coalesce. As a result, (5) shrub clusters on uplands represent an intermediate stage in the conversion of grassland to woodland, and (6) closed—canopy woodlands on more mesic sites appear to represent portions of the landscape where this has already occurred. Because the conversion of grasslands and savannas to woodlands in the Rio Grande Plains is initiated by mesquite, factors regulating its dispersal, establishment, and role as a facilitator of woody community development are emphasized.

The Role of Competition in the Spacing of Trees in a Burkea africana- Terminalia sericea Savanna

The Role of Competition in the Spacing of Trees in a Burkea africana- Terminalia sericea Savanna

Preliminary Evaluation of SEASAT-A SAR Data for Land-Use Mapping

Synthetic Aperture Radar (SAR) imagery from the unmanned Earth satellite, SEASAT-A, was examined in order to test its applicability for land-use mapping. The imagery used covers part of northern East Anglia and is from Revolution 762, acquired on 19 August 1978. A preliminary interpretation was carried out and six tone/texture radar mapping units were identified. Field-checking was then completed in each of three areas. A final classification of land-use units, which could be identified on this SEASAT-A SAR imagery, was then constructed. Mature, closed-canopy woodland and certain crop groupings can be consistently recognized on the imagery; but several other land-use categories have signatures with equal amounts of white speckle that cannot always be differentiated by eye. In such circumstances, maps and aerial photographs, as well as field-work, were used to confirm the interpretation and land-use classification so that mapping could be extended into areas where such information is not available. There is scope for both enhancement ofthe quality ofthe available imagery and for extending the study into areas of more variable terrain and land use.

Habitat Selection by Birds of Riparian Communities: Evaluating Effects of Habitat Alterations

Avifauna of riparian communities were studied in Iowa during late spring and early summer. Birds were censused on 28 study plots representing a habitat gradient from hayfields to closed-canopy woodlands. An index of nesting niche breadth was determined for 18 open-nesting bird species on the basis of vegetation life form(s) used for nesting, and for 10 cavity-nesting species on the basis of type(s) of nest-cavity support. Cavity-nesters preferred soft snags as nest sites. Floodplain woodlands supported higher densities of breeding birds than upland woodland or herbaceous habitats. Bird species richness increased (P < 0.01) with the width of wooded riparian habitats. Wooded habitats supported a maximum of 32 species; herbaceous habitats, 8. Observation frequencies of 41 bird species in 6 general habitat types were used to calculate indices of tolerance to habitat alteration. Microhabitat characteristics selected by each species were determined by comparing bird observation frequencies with 36 vegetation variables, using stepwise multiple regression. The potential effects of 6 alterations to wooded riparian habitats on the 41 species are predicted. J. WILDL. MANAGE. 44(1):1-15 Riparian habitats are critical to wildlife, especially in regions with intensive agriculture where streamside habitat is being depleted rapidly. Nongame birds constitute a major component of riparian wildlife communities, but most research concerning nongame bird management has been local in nature or concerned with endangered species (Robbins and Erskine 1975). Recently, contributors to several symposia have emphasized the need for research on management of all nongame birds (Smith 1975; DeGraaf 1978a,b). Such research is essential to assess the impacts of habitat alterations on the associated wildlife (Lennartz and Bjugstad 1975). Our study is an attempt to satisfy part of that need. Our objectives were to quantify factors critical in nest-site and habitat selection by breeding birds of riparian communities over a range of habitat types and to use the results to evaluate effects of habitat perturbations on avian communities. The results are applicable to both riparian and upland habitats of the Central Plains and, with caution, could be used in other areas as well. We are grateful to the landowners of Guthrie County, Iowa, for their cooperation in all phases of the field work. T. Rosburg and R. Deitchler assisted in collecting field data. D. F. Cox, L. Wolins, M. Hand, and B. J. Meador provided help with the statistics and computer analysis. J. J. Dinsmore, R. B. Dahlgren, and R. Q. Landers reviewed an earlier draft of the manuscript. The manuscript also benefited from the suggestions of 2 anonymous referees.

A Study of the Dynamic Ecology of Zambian Vegetation

(1) Traditionally three broad vegetation types have been recognized in northern Zambia: chipya, an open woodland subjected to intense dry-season fires; miombo, a light closedcanopy woodland dominated by species of Brachystegia and Julbernardia; and mateshi, a dry evergreen forest now reduced to remnant patches. (2) The present study formed part of an integrated land-appraisal survey of north-eastern Zambia; 398 quantitative samples (each 20 x 20 m) were recorded, and the majority were found to contain species from two or three of the above vegetation types. (3) It is suggested that there is a dynamic relation between the three vegetation types, with a trend in the absence of fire from chipya via miombo to mateshi; and that, specifically, certain chipya species form patches of low canopy which provide a suitable habitat for the establishment of a number of Uapaca spp. that are unable to grow in the open chipya. Under the protection of Uapaca the miombo and mateshi canopy species regenerate. (4) The component species have been sorted into four ecological groups-chipya, Uapaca, Brachystegia-Julbernardia woodland, and dry evergreen forest and the dynamic relationships between the groups discussed by reference to an ordination of 206 samples. (5) Topography has been shown to play a minor role in the determination of vegetative patterns. Fire is the major factor, and the dynamic vegetative patterns have been described in terms of the development of successive tree canopies that control the effects of fire.