Simulated Browsing Research Articles

Response to natural and simulated browsing of two Mediterranean oaks with contrasting leaf habit after a wildfire

In this study, we explore the response to browsing of two co-occurring Mediterranean oaks, the evergreen Quercus ilex and the deciduous Quercus cerrioides, resprouting in areas affected by large wildfires in central Catalonia (NE Spain). We tested three hypotheses: (i) differences in the preference of browsers will cause a higher impact of browsing on the deciduous oak, (ii) the deciduous oak will show a lower response to browsing than the evergreen one, and (iii) the response to browsing of Q. ilex and Q. cerrioides will differ depending on the season of the year when browsing occurs. To test the first hypothesis, we undertook the monitoring of the degree of browsing on resprouting evergreen and deciduous oaks after fire, while the second and third hypothesis were tested by mean of an experiment with different intensities of simulated browsing in different seasons of the year. The results indicate that Q. cerrioides individuals were more heavily browsed than Q. ilex ones. Moreover, browsing matched the two species in most of the size variables considered, cancelling the advantage in height and crown projection of the deciduous oak at the beginning of the resprouting process. In the experiment of simulated browsing, Q. ilex and Q. cerrioides showed a similar response to the different intensities of simulated browsing applied, but differences between species occurred depending on the season of the year when browsing occurred: Q. ilex showed a higher growth rate of crown projection than Q. cerrioides when it was browsed in autumn and winter, while the opposite pattern was obtained when stumps browsing occurred in spring and summer.

Overcompensation and adaptive plasticity of apical dominance in Erysimum strictum (Brassicaceae) in response to simulated browsing and resource availability

In the cases where overcompensation has been observed in monocarpic herbs, overcompensation is associated with an apically dominant shoot architecture of intact plants, increased lateral branching following herbivory, and increased reproductive success as a consequence of damage. The compensatory continuum hypothesis expects overcompensation to be more prevalent in resource rich environments compared to poor environments. This is paradoxical since in resource rich conditions the intact plants should branch most vigorously and hence any further increase in branch number should lead to lower seed yield. An explanation could be that apical dominance is rather insensitive to changes in resource availability, and that overcompensation is possible in conditions where plants experience meristem limitation (due to apical dominance) in relation to available resources.We explored the branching patterns and fitness responses of tall wormseed mustard (Erysimum strictum) to simulated browsing, soil nutrients, and competition in common garden. Competition increased apical dominance and reduced plant fitness whereas fertilization had the reverse effects. Simulated browsing increased lateral branching and had little impact on plant fitness. Fitness overcompensation was observed only among plants grown in competition and in the absence of fertilization – the most resource poor treatment combination in the experiment. The results contradict both with the compensation continuum and the assumption that apical dominance shows no or very little plasticity in relation to growing conditions. Because directional selection gradients on branch number were invariantly positive irrespective of growing conditions, we propose that, in spite of phenotypic plasticity of apical dominance, the plants appear to be meristem rather than resource limited, and that meristem limitation is strongest in conditions where intact plants produce fewest lateral branches. Our results deviate from the compensation continuum because resource availability affected compensation ability more strongly through phenotypic plasticity of shoot architecture rather than via changes in resource availability per se.

DIFFERENT MOOSE DENSITIES AND ACCOMPANIED CHANGES IN TREE MORPHOLOGY AND BROWSE PRODUCTION

Large herbivores affect the morphology and productivity of their food plants, which in turn affects food availability and foraging efficiency. These effects can occur directly, through tissue removal, or indirectly through additions of nutrients in dung and urine. Although influences of herbivores on plant communities are well established for grazers, less is known about the effects of browsers. We studied how tree morphology (number of shoots, shoot mass, and mean yearly height increase) and production of winter browse of Scots pine (Pinus sylvestris) and birch (Betula pubescens and B. pendula) responded to simulated moose herbivory in Swedish boreal forests. We simulated browsing, defecation, and urination to represent effects of four levels of moose density in each of eight exclosures. To be able to study the whole range of moose impact and obtain better mean estimates from the ecosystem perspective, the eight exclosures were placed along a forest productivity gradient. Treatments were applied for three consecutive years. For both birch and pine, the mean average number of shoots per tree and the mean yearly height increase decreased with increasing biomass removal. Mass of individual shoots increased for birch, but not for pine. The mean yearly production of winter browse (per m2) was significantly reduced by biomass removal. The responses of birch followed a threshold model predicting no effect up to a low to moderate level of biomass removal, and thereafter a linear decrease, although the model describing constant linear decrease not could be ruled out (model selection based on Akaike Information Criterion). The response of pine followed a threshold model. We concluded that winter browse might be in shortage at high browsing pressure over extended time, but most woody plants eaten by moose should sustain browsing pressure at moose densities common in many areas in Sweden.

Do competition and herbivory alter the internal nitrogen dynamics of birch saplings?

Deciduous trees recycle nitrogen within their tissues. The aim of this study was to test the hypothesis that reductions in plant growth, caused by competition and herbivory, reduce the sink strength for N during autumn nutrient withdrawal, and reduce the storage capacity and hence the amount of N remobilized in the following spring. We used (15)N-labelled fertilizer to quantify N uptake, leaf N withdrawal and remobilization. Betula pubescens saplings were grown with either Molinia caerulea or Calluna vulgaris, and subjected to simulated browsing damage. Competition reduced B. pubescens leaf N withdrawal and remobilization, with C. vulgaris having a greater effect than M. caerulea. However, simulated browsing had no significant effect on sapling N dynamics. The patterns of leaf N withdrawal and remobilization closely followed sapling dry mass. We conclude that the effect of competition on sapling mass reduces their N-storage capacity. This reduces sink strength for leaf N withdrawal and the source strength for remobilized N. The ability of saplings to compensate for browsing damage removed any potential effect of browsing on N dynamics.

Inducing condensed tannin production in Colophospermum mopane: Absence of response to soil N and P fertility and physical damage

The effects of available soil N and P and the effect of simulated browsing (leave removal) on foliar condensed tannin (CT) concentration were tested on young Colophospermum mopane (J. Kirk ex Benth) J. Leonard (Mopane) plants. Although clear differences in growth occurred between different levels of soil N, no differences in foliar CT concentration were found. Changes in available soil P and physical damage did not affect the plant growth or chemical composition. The complete absence of response of CT concentration to physical damage and soil nutrients may be related to the age of the trees in this study. It is proposed that existing theories on the interaction between soil properties and carbon based defences in trees are expanded, to include the potential responses of young trees to different soil nutrient levels.

Changes in tree growth resulting from simulated browsing have limited effects on soil biological properties

Herbivores can indirectly affect ecosystem productivity by modifying feedbacks that occur between dominant plants and below-ground properties, especially through altering nutrient availability in soil. The aim of this study was to examine, under controlled conditions, the effect of simulated browsing by large herbivores on the growth characteristics of downy birch ( Betula pubescens), a dominant tree species of native regenerating forests in northern Britain, and to determine how effects of browsing on tree growth cascaded through to soil microbial communities, thereby affecting nutrient availability in soil. Downy birch seedlings were grown in mesocosms for 2 years and subjected to simulated browsing in the form of defoliation and clipping treatments. Upon destructive harvest, a number of measures of both tree growth characteristics and soil biological and nutrient properties were made. Clipping of birch trees significantly reduced total root biomass (27%), fine root biomass (29%), coarse root biomass (27%) and above-ground biomass (18%), whereas defoliated trees were significantly shorter than non-defoliated trees. Despite these significant and negative effects of browsing on tree growth, soil biological properties remained largely unaffected, other than rates of N mineralisation, which were greater under defoliated trees. We conclude that other factors, such as herbivore effects on litter quantity and quality which feedback to soil biological properties in the longer-term are more important in determining ecosystem responses to browsing.

Clipping Frequency Affects Canopy Volume and Biomass Production in Planeleaf Willow (Salix planifolia var. planifolia Prush)

Willows (Salix) are often a key component of riparian ecosystems and are often browsed by both wildlife and livestock. However, little is understood about how the frequency of browsing affects aboveground and belowground willow production. The objectives of this study were to determine how the frequency of simulated browsing events in a controlled environment affected 1) the aboveground, belowground, and total biomass production and 2) the canopy volume of planeleaf willow (Salix planifolia var. planifolia Prush) plants. The experiment was a completely randomized block design consisting of 2 groups of willow plants with different clipping histories. Within each group, plants were randomly assigned to 1 of 11 subgroups. Clipping events comprised of all combinations of early, middle, and late season periods were imposed on the treatment subgroups, while 1 subgroup served as the control. Canopy volume measurements were made before and after each clipping event. Canopy volume change was related to the harvested twig length (cm) and weight (g). Results suggested that frequency of clipping alone did not explain differences in aboveground and belowground willow production. Instead, willow production was influenced by an accumulation of specific combinations of seasonal clipping events and was dependent on the clipping history of the plants. Early season clipping, alone or in combination with other events, was more detrimental to willows with prior clipping histories than middle or late season clipping treatments. Willow with prior clipping histories treated in either the middle or late seasons, and the late/middle combination produced more than the controls. These results should be verified in willow communities subjected to natural environmental variations and browsing.

Clipping Frequency Affects Canopy Volume and Biomass Production in Planeleaf Willow (Salix planifolia var. planifolia Prush)

Willows (Salix) are often a key component of riparian ecosystems and are often browsed by both wildlife and livestock. However, little is understood about how the frequency of browsing affects aboveground and belowground willow production. The objectives of this study were to determine how the frequency of simulated browsing events in a controlled environment affected 1) the aboveground, belowground, and total biomass production and 2) the canopy volume of planeleaf willow (Salix planifolia var. planifolia Prush) plants. The experiment was a completely randomized block design consisting of 2 groups of willow plants with different clipping histories. Within each group, plants were randomly assigned to 1 of 11 subgroups. Clipping events comprised of all combinations of early, middle, and late season periods were imposed on the treatment subgroups, while 1 subgroup served as the control. Canopy volume measurements were made before and after each clipping event. Canopy volume change was related to the harvested twig length (cm) and weight (g). Results suggested that frequency of clipping alone did not explain differences in aboveground and belowground willow production. Instead, willow production was influenced by an accumulation of specific combinations of seasonal clipping events and was dependent on the clipping history of the plants. Early season clipping, alone or in combination with other events, was more detrimental to willows with prior clipping histories than middle or late season clipping treatments. Willow with prior clipping histories treated in either the middle or late seasons, and the late/middle combination produced more than the controls. These results should be verified in willow communities subjected to natural environmental variations and browsing.

Impact of moose population density on the production and composition of litter in boreal forests

Recent studies of ungulates have revealed that selective foraging seems to be an important mechanism by which they can affect the structure and species composition of the plant community, and thus quantity (dry mass) and quality (chemical composition) of litter available for decomposers. Such changes in litter production may be especially important in N‐limited systems like boreal forests. We chose moose (Alces alces) as study species to investigate this mechanism. Moose browse mainly in the tree and shrub layers year round, and because of their wide distribution and often high population densities, they can have a significant effect on litter production of trees and shrubs in Swedish boreal forests. The effects of herbivores may also vary along productivity gradients. We therefore simulated browsing and urine and fecal deposition corresponding to 4 different moose densities in exclosures along a pre‐existing forest productivity gradient. Both litter quantity (g dry mass per m2 and year) and contributions of C and N (g dry mass per m2 and year) decreased with increasing level of simulated moose density. High moose densities over extended time can therefore reduce N contributions to soil and therefore eventually reduce site productivity in Swedish boreal forests. This effect of moose was mainly a result of decreased litter quantity, because contradictory to studies from North America, litter quality (C:N ratio and N contribution per mass unit of litter) was not affected by level of simulated moose density.

How does timing of browsing affect above‐ and below‐ground growth of Betula pendula, Pinus sylvestris and Sorbus aucuparia?

Plant responses to browsing can affect root and shoot morphology, which is important to subsequent herbivory, nutrient acquisition and competition. This paper examines the above‐ and below‐ground responses of three browse species, with different growth strategies, to simulated browsing damage at different times of year. Saplings were grown in pots in sand culture to enable whole sapling analysis. At winter dormancy or budburst, 50% of previous year's shoots (and associated leaves/buds) were clipped. Subsequent sapling growth and morphology was compared with that of unclipped control saplings. Treatment differences in growth parameters of each species were observed, including changes in branching patterns, shoot lengths, diameters and ratios, leaf sizes and end‐of‐season bud numbers. Some responses were damage‐induced per se; others differed according to timing of damage. Compensatory growth by the two deciduous species (Betula pendula, Sorbus aucuparia) resulted in few biomass differences by the end of the year of damage as compared to controls, but both above‐ and below‐ground growth of clipped Pinus sylvestris was poor, particularly those damaged at budburst, giving strong differences between control, dormant, and budburst clipped saplings.

Morphological responses of woody species to simulated twig-browsing in Botswana

Increased shoot growth has recurrently been recorded following real or simulated shoot browsing, although responses may vary between different woody species. We investigated morphological responses to simulated dry-season browsing on Colophospermum mopane, Acacia tortilis, Grewia flava, Peltophorum africanum and Ziziphus mucronata, which differ in growth rate, occurrence of spines and use by mammalian herbivores. Treatment groups included a control, four clipping intensities and cutting at ground level. Responses were monitored during the following growth season on three annual shoots, located in the bottom, middle and top height interval, on each sapling. All five species showed compensatory growth responses, although no obvious relation was found between the strength of responses and growth rate or natural browsing pressure. The general pattern was an increased shoot length, shoot diameter, number of lateral shoots and shoot biomass with increased clipping intensity. These responses are probably an effect of the reduction of competing growing points and disrupted apical dominance. Growth responses were stronger in shoots with higher location on the sapling, which may reflect the pressure on saplings to attain a certain height to avoid browsing, reproduce and increase resistance to fire. We found no evidence of the number of spines being an induced defence in either of the two spinescent species studied.

Effects of natural and simulated herbivory on spine lengths of Acacia drepanolobium in Kenya

We present experimental evidence supporting the hypothesis that increased spine length in acacia species is a defense induced by herbivory. Acacia drepanolobium is the dominant tree over large areas of East Africa. Each individual tree is occupied by one of four ant species at our study site. Using two types of electric fences, we have effectively controlled herbivory by megaherbivores (elephants and giraffes) and other large mammalian herbivores at a field site in Laikipia, Kenya since 1995. Mean spine lengths of new spines on trees occupied by the most abundant ant species (presumed to be a defensive mutualist) have shown a slow and steady decline over the first five years of the experiment on branches protected from these herbivores. This reduction has been 35–40%, or approximately half of the reduction in spine length that we anticipate will eventually occur, based on trees that have been protected from herbivory for many years. In contrast, trees occupied by a resident ant species that systematically prunes shoots have shown no reduction in spine length associated with herbivore exclusion treatments. Experimental pruning of shoots similar to that carried out by this ant species resulted in longer spines on seedlings in a greenhouse setting. Simulated large mammal browsing in the field rapidly (re‐)induced greater spine lengths on trees that had been protected from large mammals for five years. The slow relaxation of spine length in the absence of herbivory, contrasted with its rapid induction after simulated browsing, suggests that there is a difference in the reliability of these two signals. Spine length responses to herbivory were extremely local (limited to individual branches). These branch‐specific responses are consistent with the hypothesis that induced defense in this system evolved in the context of within‐tree spatial variation in herbivore pressure, in particular variation in branch height.

Effects of willow hybridisation and simulated browsing on the development and survival of the leaf beetle Phratora vitellinae

BackgroundInterspecific hybridisation is common between many plant species and causes rapid changes in a variety of plant characters. This may pose problems for herbivores because changes in recognition characters may be poorly correlated with changes in quality characters. Many studies have examined different systems of hybrids and herbivores in attempts to understand the role of hybridisation in the evolution of plant resistance. The results from different systems are variable. Studies of hybrids between Salix caprea (L., Salicaceae) and S. repens show that they are intermediate between the two parental species in most resistence characters. However, a plants herbivore resistence depends also on its biotic and abiotic environment. Important biotic factors that may influence plant growth and plant chemistry include the interactions between different herbivores that occur through their exploitation of common host plants. Although the effects on plants of previous herbivory are likely to be strongly affected by environmental conditions, they are also species-specific. Damage may therefore have different effects on hybrids than on their parental species, and this could influence the performance of herbivores on pure and hybrid species of plants. To evaluate the effects of hybridisation on insect performance, the development and survival rates of Phratora vitellinae (L. 1758, Coleoptera: Chrysomelidae) larvae on pure S. repens, pure S. caprea and Fl hybrids of the two species was monitored. Further, to examine the effect of herbivorous mammals on the performance of the larvae, plants were damaged to simulate winter foraging by voles or spring leaf stripping by moose.ResultsThe results show that development rates were highest on S. repens and equally low on S. caprea and the Fl hybrid. In addition, development of the plants treated to simulate mammalian herbivore damage was slower than that of corresponding controls.ConclusionsThe results of this experiment suggest that P. vitellinae has a higher development rate, and thus probably higher performance, on species with high concentrations of phenolic glucosides. Therefore, it would be of adaptive benefit for P. vitellinae females to have an ovipositional preference for S. repens, compared to S. caprea and intermediate preference for Fl hybrids. The faster development observed on S. repens supports the hypothesis that P. vitellinae obtains additional adaptive benefits from phenolic glucosides beyond protection against predators. Therefore, it is important to consider further factors, such as damage caused by other herbivores, when studying this hybrid complex.

Relationship of Periploca laevigata (Asclepidaceae) tannins to livestock herbivory

Periploca laevigata is an abundant and palatable tannin-containing shrub present in the south-east coastal area of Spain. Sheep and goats usually consume this species, which represents 7·2% of total dry matter (DM) intake per year. Periploca laevigata is an important grazing species in the dry season, despite its high tannin content. The objective of the present work was to examine the tannin level of P. laevigata in relation to the extent of utilization by small ruminants, as well as in response to simulated browsing. Periploca sprouts were collected in three areas from plants exhibiting either medium (0·51 animals/HA), low (0·34 animals/HA) or no (0 animals/HA) browsing by small ruminants. These sprouts were also collected in plants with simulated herbivory twice (in two successive months), once, and with no simulated herbivory. A greater concentration of tannins ( p<0·001) was detected in the sprouts of plants experiencing greater damage (3·3%, 2·0% and 1·2% w/w in DM basis for high-, medium- and low-stocking rates, respectively). Similarly, a greater tannin concentration ( p=0·037) was documented in the sprouts subjected to simulated browsing (4·8%, 4·2% and 3·8% w/w in DM basis for two, one or no browsing, respectively). In summary, P. laevigata increases the level of tannins under higher grazing pressure. Nevertheless, this response does not seem to be effective in defending these plants against herbivores, as the livestock consumes them, perhaps because animals browse P. laevigata moderately throughout the day, mixing it with other plants, or because they possess some kind of physiological mechanism to overcome the effects of tannins.

Effects of Simulated Browsing and Length of Growing Season on Leaf Characteristics and Flowering in a Deciduous Arctic Shrub, Salix polaris

Plants respond to herbivory either by maximizing resource acquisition and compensatory growth or by minimizing loss of resources, e.g., by investing in chemical or structural defence. We studied the response to simulated browsing by the deciduous dwarf shrub, Salix polaris, on high Arctic Spitsbergen. Salix polaris is browsed by Svalbard reindeer, and its response to browsing may influence subsequent utilization. We compared leaf characteristics and flowering of S. polaris from areas with relatively short, intermediate, and long growing season, and their responses 1 yr after simulated browsing in early, mid, and late summer. Leaf numbers, total and individual biomass of leaves, and the number of inflorescences were greatly reduced the year after treatment. There was no increase in phenolics but a tendency to an increase in N content in the leaves of S. polaris 1 yr after treatment. Salix polaris showed little variation in the response to simulated browsing with local variation in resource availability (length of growing season) or with time of browsing. The results suggest that S. polaris responds to summer browsing the previous year by allocating resources to compensatory growth rather than to defence. For reindeer, browsing of S. polaris leads to a sizeable decrease in food quantity and, possibly, to a limited increase in food quality.

Effects of Simulated Browsing and Length of Growing Season on Leaf Characteristics and Flowering in a Deciduous Arctic Shrub, Salix polaris

Effects of Simulated Browsing and Length of Growing Season on Leaf Characteristics and Flowering in a Deciduous Arctic Shrub, Salix polaris

Effects of simulated winter browsing and drought on growth of Quercus robur L. seedlings during establishment

The response to simulated winter browsing and a period of drought was studied on 2-year-old Quercus robur L. seedlings in an experiment in a daylight climate chamber. The seedlings were planted in May and subjected to treatments. The experiment had a factorial design with two treatment factors, clipping and watering, each with two levels, clipping or no clipping and well-watered or droughted. In September, the seedlings were harvested and separated into leaves, new shoots, old shoots and root, which were weighed and measured. No significant interactions were found between clipping and watering. The watering treatment had a larger effect on seedling growth than the clipping treatment. Clipped seedlings had about the same leaf and shoot growth as unclipped ones.

Application of a forest gap model for prediction of browsing effects on riparian forest succession

Selective browsing by white-tailed deer ( Odocoileus virginianus) severely impacts seedling dynamics within riparian forests on the Patuxent Research Refuge, MD. To evaluate the long-term implications of browsing for forest dynamics, field studies of seedling recruitment, seedling growth, and photosynthetic performance are used to adapt a forest gap model (ZELIG) for simulating browsing interactions with tree species life history characteristics. Primary alterations to the model include addition of small seedling demography, soil saturation effects, shade adaption of tree photosynthesis, and browsing algorithms. Simulated stands were subjected to browsing as a function of total seedling density. If a stand is browsed, then seedling species are browsed selectively based on deer feeding preferences. Model output without browsing impacts closely matches current riparian forest composition. Simulated browsing depresses total forest basal area during mid-succession by reducing regeneration and growth of early successional yellow poplar ( Liriodendron tulipifera), allowing late successional American beech ( Fagus grandifolia) to gain earlier dominance. Greater browsing intensities increase the impact on basal area and displace overall forest composition further from control conditions. Control and browsing simulations converge toward an American beech dominated forest in late succession. Thus browsing interacts with tree species life history strategies to alter the rate of succession, but not the long-term trajectory of succession. Further advances in simulating the impacts of deer browsing will benefit from incorporating landscape-scale deer population dynamics and spatially explicit distributions of forest trees.

The effect of plant competition and simulated summer browsing by deer on tree regeneration

SummaryDuring the last decade the use of natural regeneration has become an accepted method of restocking British woodlands after harvesting. However, in many broadleaved woodlands there are insufficient numbers of established tree seedlings of adequate size to ensure that restocking is successful. This lack of seedlings may be related to a number of factors, including competition from the ground flora and browsing by deer.The numbers of deer (Capreolus capreolus,Cervus elaphusandDama dama) are rising throughout Britain and population densities frequently exceed those known to have a significant impact on broadleaved trees. This experiment, which took place at four sites over a 5‐year period, studied the effects of competition from the ground flora and severe, simulated, browsing by deer during summer, on the growth and mortality of naturally occurringAcer pseudoplatanus,Fraxinus excelsior,Fagus sylvaticaandQuercus roburseedlings.The seedlings were initially 30–40 cm tall with stem diameters of 2·6–6·2 mm. Competition from the ground flora was removed by maintaining circular areas, 1 m in diameter, free of vegetation using a general herbicide. Browsing was simulated by clipping new shoots that were longer than 1 cm in June and August.The control of the ground flora had little effect on the growth and survival of seedling trees.In general, the number of tree seedlings producing sufficient growth to receive the simulated browsing treatment decreased with time, but for those seedlings that were clipped there were no consistent trends in either numbers or weights of shoots removed. Unclipped seedlings continued to grow. The height and stem diameter increments varied with species and site, but after 5 years unclipped plants were 50–200% taller with stem diameters 20–130% greater than at the start of the experiment.The mortality of unclipped seedlings was low and 80% or more survived. Clipping significantly reduced the survival ofFraxinus excelsiorandA. pseudoplatanus, butQ. roburandFagus sylvaticawere unaffected. On an annual basis, there was no relationship between mortality and accumulated number or dry weight of shoots clipped, initial stem diameter or height, and whether or not the seedling was under the overstorey canopy.The results from this study indicate that established seedlings ofA. pseudoplatanus,Fraxinus excelsior,Fagus sylvaticaandQ. roburthat are &gt; 30 cm tall can survive several years of severe browsing under the shade provided by overstorey canopy covers of 50% or more. This suggests that management should aim to improve survival during the first 1–2 years of growth. This may be achieved by exclusion of animals by fencing, protection of individual seedlings using tree shelters, or culling to control herbivore numbers.

Plant responses and herbivory following simulated browsing and stem cutting of Combretum apiculatum

Abstract. Time and mode of herbivory on savanna trees and their subsequent responses are dependent on, among other things, earlier herbivory and fire. We used clipping (simulated browsing) and stem cutting (simulated heavy browsing and to some extent simulated fire) to evaluate such interactions. Study organisms were a deciduous, broad‐leaved tree species, Combretum apiculatum (Combretaceae), browsing large herbivores and leaf‐eating insects. The treatments were done in the late dry season before bud break. Late in the following wet season, we recorded plant responses to treatment and browsing. The treated trees, especially the cut ones, responded by producing larger and fewer annual shoots. Compared to control trees, there was a slight increase in shoot biomass of clipped trees and a strong reduction of cut ones. Leaf area increased in clipped trees, but decreased in cut ones. A marked increase in the number of browsed trees was recorded amongst treated trees. Number of bites, consumption and utilization also increased with severity of treatment. In contrast, insect herbivory was reduced on both clipped and cut trees. The observed patterns are discussed in relation to current ideas on plant ‐ herbivore interactions.