Shrub Control Research Articles

Outcomes of control and monitoring of a widespread riparian invader (Tamarix spp.): a comparison of synthesis approaches

Effective ecological restoration requires empirical assessment to determine outcomes of projects, but conclusions regarding the effects of restoration treatments on the whole ecosystem remain rare. Control of invasive shrubs and trees in the genus Tamarix and associated riparian restoration in the American Southwest has been of interest to scientists and resource managers for decades; dozens of studies have reported highly variable outcomes of Tamarix control efforts, as measured by a range of response variables, temporal and spatial scales and monitoring strategies. We conducted a literature search and review, meta-analysis and vote count (comparison of numerical outcomes lacking reported variances and/or sample sizes) on published papers that quantitatively measured a variety of responses to control of Tamarix. From 96 publications obtained through a global search on terms related to Tamarix control, we found 52 publications suitable for a meta-analysis (n = 777 comparisons) and 63 publications suitable for two vote counts (n = 1,460 comparisons total; 622 comparisons reported as statistically significant) of response to Tamarix control. We estimated responses to control by treatment type (e.g. cut-stump treatment, burning, biocontrol) and ecosystem component (e.g. vegetation, fauna, fluvial processes). Finally, we compared results of the various synthesis methods to determine whether the increasingly stringent requirements for inclusion led to biased outcomes. Vegetation metrics, especially measures of Tamarix response, were the most commonly assessed. Ecosystem components other than vegetation, such as fauna, soils and hydrogeomorphic dynamics, were under-represented. The meta-analysis showed significantly positive responses by vegetation overall to biocontrol, herbicide and cut-stump treatments. This was primarily due to reduction of Tamarix cover; impacts on replacement vegetation were highly variable. We found concordance amongst our varied synthesis approaches, indicating that increased granularity from stricter quantitative techniques does not come at the cost of a biased sample. Overall, our results indicate that common control methods are generally effective for reducing Tamarix, but the indirect effects on other aspects of the ecosystem are variable and remain understudied. Given that this is a relatively well-studied invasive plant species, our results also illustrate the limitations of not only individual studies, but also of reviews for measuring the impact of invasive species control. We call on researchers to investigate the less commonly studied responses to Tamarix control and riparian restoration including the effects on fauna, soil and hydrogeomorphic characteristics.

Benefits of fire in shrub control in the grasslands of the monte province, Rio Negro, Argentina

In the grasslands in the NE of Río Negro province, Argentina controlled burning or mechanical clearing are common practices to reduce the shrub layer and improve the forage supply of the grasslands that constitute the basis of extensive livestock breeding. In one area of the region, we estimated the Aerial Net Primary Productivity (ANPP) and evaluated the quality of the dominant grasses over three years in grasslands subjected to mechanical clearing and burning, through seasonal cuts of biomass and laboratory analysis. We also recorded the phenology of the dominant grasses and shrubs. We obtained higher values of Crude Protein and Dry Matter Digestibility of the grasses in spring, since they were mainly in the vegetative stage, and the differences were significantly greater in the burned site. This effect of fire would be due both to the regrowth and to the increase in the proportion of vegetative material generated by this disturbance. Mechanical clearing had no significant effects on quality, although it increased the ANPP. When analyzing phenological behavior, our results showed better conditions for livestock production in the disturbed sites, with a higher proportion of vegetative growth of the grasses and greater senescence of the shrubs.

Non-hazardous rapeseed oil spray adjuvants do not improve the rainfastness or effectiveness of glyphosate for Rhododendron ponticum shrub control

Non-hazardous rapeseed oil spray adjuvants do not improve the rainfastness or effectiveness of glyphosate for Rhododendron ponticum shrub control

Response of herbaceous functional types and woody vegetation to selective shrub control on wildlife and cattle ranches in a semi‐arid savanna

AbstractAimsShrub encroachment is a major challenge for livestock and wildlife management in semi‐arid savannas. Shrub removal by land managers is widespread, but the long‐term effects on vegetation structure and composition, which determine carrying capacity for herbivores, are poorly documented. This study aims to examine the effects of selective shrub removal to guide vegetation management in key land uses of semi‐arid African savannas.QuestionsVegetation responses were assessed across land uses and treatments to answer the following questions: (1) does shrub removal increase the frequency of palatable plants and therefore herbivore‐carrying capacity; (2) does selective shrub removal decrease woody vegetation structure 15 years after application; and (3) how do these effects differ between cattle and wildlife ranching?LocationMolopo region of the North West Province, South Africa.MethodsHerbaceous and woody vegetations were sampled within six transects each of three wildlife ranches and three cattle ranches in areas that had either been selectively shrub‐controlled with herbicides 10–15 years previously or left untreated. To quantify effects of woody shrub control on herbaceous functional‐group abundances and assemblages, tree equivalents, regrowth rate, and shrub abundance, we compared these variables across two treatments (treated and untreated) and land uses. Data were analysed using GLMMs, NMDS ordinations, PERMANOVA, and SIMPER.ResultsSelective shrub control effectively improved palatable herbaceous vegetation, especially on cattle ranches. Especially abundance of perennial grass was higher on wildlife ranches compared to cattle ranches. Tree equivalent was higher in untreated compared to treated plots, and these differences were more pronounced on wildlife ranches than on cattle ranches.ConclusionssSelective shrub removal improved the palatable herbaceous layer for both wildlife and cattle ranching and can be considered an effective management strategy in semi‐arid rangelands.

Reduced hack and squirt treatment with aminocyclopyrachlor and aminopyralid for invasive shrub control

AbstractInvasive shrubs often present extremely difficult challenges for individual plant treatment approaches due to multiple basal stems with complex branching patterns. Basal bark and cut stump individual plant treatments have been the standard methods for managing large-statured shrubs, while hack and squirt has been disregarded as operationally too difficult. However, hack and squirt is a more discriminant treatment technique that may lead to a reduction in herbicide use. Here, we evaluated the speed, herbicide use, and performance of a reduced hack and squirt approach using single hacks per stem injected with 0.5 ml of either aminocyclopyrachlor (240 g L−1) or aminopyralid (240 g L−1) against conventional low-volume basal bark treatment with triclopyr ester (96 g L−1) and cut stump treatment with triclopyr amine (180 g L−1). The experiments were conducted on three subtropical shrub species: Eugenia uniflora, Lagerstroemia indica, and Schinus terebinthifolia. Across species, we found the reduced hack and squirt approach resulted in comparable treatment efficacy to basal bark and cut stump treatment, was faster than cut stump treatment, and used less herbicide and carrier than basal bark treatment. A single hack per stem is a significant shift for hack and squirt treatment, which typically employs a narrow or continuous spacing of hacks around the entire circumference of each stem. Future work should seek to clarify the applicability of this approach over a wide range of invasive shrubs.

Impacts of selective bush control on herbaceous diversity in wildlife and cattle land use areas in a semi-arid Kalahari savanna

Climate change and inappropriate management practices in semi-arid savannas often result in shrub encroachment. Chemical shrub control is a common rehabilitation measure to counter shrub encroachment. A recent development, particularly in southern Africa, is the conversion from cattle to wildlife farming. Cattle and wildlife exhibit different behaviours, and different management practices are used. How these differences affect the results of rehabilitation measures is not well known. Here, we compared how selective chemical shrub control in these two land uses affected herbaceous diversity, and composition along waterhole transects (proxy for grazing pressure). Shrub control increased Simpson diversity when both land uses were analysed together, while land use type did not affect any diversity measure. However, when land uses were analysed individually, spatial differences in diversity became apparent. Species richness in game farms was affected by shrub control only at distances greater than 300m from waterholes, and in cattle farms total abundance increased at 1000m distances. Eleven species contributed to compositional differences between land uses. Our results show that bush control can improve ecosystem functioning and habitat heterogeneity in both land use types, which is particularly important given the current transition from livestock to game farming in southern Africa.

Strong relationships between urbanization, landscape structure, and ecosystem service multifunctionality in urban forest fragments

Urban forest fragments are highly multifunctional and provide many ecosystem services to people. However, the expansion and densification of cities is threatening this particular type of urban forest, resulting in further fragmentation, degradation and a change in forest function. Understanding how urbanization affects urban forests fragments and the multiple ecosystem services they provide is important for the creation of livable cities. We used an urban-to-rural gradient in Maple Ridge, Canada, to explore relationships between urban forest structure, urbanization, surrounding landscape structure, and the supply of eight different ecosystem services, including merchantable timber, carbon storage, flood control, food (berries), non-native shrub control, cultural use, and habitat provision. We found that the supply of multiple ecosystem services was higher at the rural end of our gradient and that forest fragments spaced closer together showed strong negative associations with most services. Crucially, forest fragment size had very weak effects on most services, emphasizing the importance of conserving small urban forest fragments with large trees. We also identified key tree genera, including Picea and Thuja, that could be retained or planted in urban forests to maximize individual services and multifunctionality. Our results highlight the potential for strategically managing urban landscapes to maintain forest fragments and enhance their ability to provide ecosystem services and multifunctionality. Our findings are relevant to inform urban conservation and greening strategies in cities around the world that are currently expanding into surrounding forests or losing greenspace through densification.

Circum‐Arctic distribution of chemical anti‐herbivore compounds suggests biome‐wide trade‐off in defence strategies in Arctic shrubs

Spatial variation in plant chemical defence towards herbivores can help us understand variation in herbivore top–down control of shrubs in the Arctic and possibly also shrub responses to global warming. Less defended, non‐resinous shrubs could be more influenced by herbivores than more defended, resinous shrubs. However, sparse field measurements limit our current understanding of how much of the circum‐Arctic variation in defence compounds is explained by taxa or defence functional groups (resinous/non‐resinous). We measured circum‐Arctic chemical defence and leaf digestibility in resinous (Betula glandulosa, B. nana ssp. exilis) and non‐resinous (B. nana ssp. nana, B. pumila) shrub birches to see how they vary among and within taxa and functional groups. Using liquid chromatography–mass spectrometry (LC–MS) metabolomic analyses and in vitro leaf digestibility via incubation in cattle rumen fluid, we analysed defence composition and leaf digestibility in 128 samples from 44 tundra locations.We found biogeographical patterns in anti‐herbivore defence where mean leaf triterpene concentrations and twig resin gland density were greater in resinous taxa and mean concentrations of condensing tannins were greater in non‐resinous taxa. This indicates a biome‐wide trade‐off between triterpene‐ or tannin‐dominated defences. However, we also found variations in chemical defence composition and resin gland density both within and among functional groups (resinous/non‐resinous) and taxa, suggesting these categorisations only partly predict chemical herbivore defence. Complex tannins were the only defence compounds negatively related to in vitro digestibility, identifying this previously neglected tannin group as having a potential key role in birch anti‐herbivore defence.We conclude that circum‐Arctic variation in birch anti‐herbivore defence can be partly derived from biogeographical distributions of birch taxa, although our detailed mapping of plant defence provides more information on this variation and can be used for better predictions of herbivore effects on Arctic vegetation.

Alien woody plants on the retaining walls of the Vistula boulevards in Kraków, southern Poland

Introducing alien plants for urban horticulture and forestry may lead to their naturalisation and invasion, bringing new challenges to protecting native biodiversity and cultural heritage in urban areas. Many old buildings and monuments are threatened by invasive trees and shrubs, which can damage their structure by physical and physiological root processes and by increasing biomass of above-ground parts. The study aimed to determine the floristic composition and abundance of alien woody plants occurring on the historic retaining walls of the Vistula boulevards in Kraków, southern Poland. A total of 11 alien woody plant species were recorded in 2022, including some invasive species in Poland, such as Acer negundo, Ailanthus altissima, Fraxinus pennsylvanica, Juglans regia, Parthenocissus quinquefolia, Robinia pseudoacacia and Rosa rugosa. Most of the species showed low abundance (less than 50 individuals) in each of the distinguished age classes (seedling, juvenile and mature individuals), except vines, which in some places occupied relatively large surfaces of the walls (more than 25 m2). Regular control and monitoring of trees and shrubs are recommended to properly protect the retaining walls of the Vistula boulevards in Kraków.

Természetvédelmi élőhelykezelés hatása a gyöngyösi Sár-hegy gyepterületeinek vegetációjára

We studied the vegetation of grasslands on the Sár Mountain, in Gyöngyös. The areas are mowed regularly by the Bükk National Park and mechanical shrub control was done as well. The effects of these habitat management techniques were investigated on grasslands of different degradation levels. Coenological studies were made between May and June in 2013 with 2×2 m relevés. The study areas were characterised according to nature conservation value categories and life forms. Our results showed that the above mentioned management techniques had positive effects on the diversity of grasslands. On the managed grasslands the abundance of woody species decreased, while the abundance of annual and perennial grass species and dicotyledonous herbaceous species increased. The highest species number (58-78) was recorded in the case of control areas. The number of species was high (47-49) in the areas managed by mowing and mechanical shrub control. The lowest species number (43) was recorded in the areas which were not mowed after mechanical shrub control. According to the nature conservation value categories the number of protected species was the highest in the control areas. Our results approved that regular mowing is needed after mechanical shrub control to sustain the diversity of abandoned grasslands in the long run.

The role of brush encroachment in Mediterranean ecosystems: a review

Abstract Encroachment of woody plants into grasslands and subsequent brush management are among the most prominent changes occurring in arid and semiarid ecosystems over the past century. The reduced number of farms, the abandonment of marginal land and the decline of traditional farming practices have led to encroachment of the woody and shrubby components into grasslands. This phenomenon, specifically in the Mediterranean region, which is followed by a reduction in herbage production, biodiversity and increased fire risk, is generally considered an undesirable process. Sarcopoterium spinosum has had great success in the eastern Mediterranean as a colonizer and dominant bush species on a wide variety of sites and climatic conditions. In the Mediterranean dehesa, the high magnitude and intensity of shrub encroachment effects on pastures and on tree production were shown to be dependent on temporal variation. Accordingly, there are attempts to transform shrublands into grassland-woodland matrices by using different techniques. The main management interventions that are commonly used include grazing, woodcutting, shrub control with herbicides or by mechanical means, amelioration of plant mineral deficits in the soil, and fire. However, the effects of these various treatments on the shrubs under diverse environmental conditions were found to be largely context-specific. As such, the most efficient option for suppressing encroachment of shrubs is combining different interventions. Appropriate management of grazing, periodic control of the shrub component, and occasional soil nutrient amelioration can lead to the development of attractive open woodland with a productive herbaceous understory that provides a wider range of ecological services.

The Use of Herbicides in South American Dry Forests to Control Shrub Encroachment: a New Threat to Cactus Species? A First Assessment

Dry forests are home to an important diversity of cactus species. In the Americas, these forests are under an increasing pressure due to a growing demand for land to produce pastures for cattle; in addition, the use of herbicides to control shrub encroachment is increasing. As a scientific collaborator of the Environmental Police of Córdoba province, Argentina, I had the opportunity to visit five cattle ranches where herbicides were illegally applied. The product used is Pastar, produced by Dow Agrochemical, and is composed of two hormonal herbicides, aminopyralid and fluroxypyr. Since all ranch owners are in legal dispute with the government, it was not possible to conduct a quantitative research. Therefore, I recorded all cactus species present and their sanitary conditions. A total of nine cactus species were recorded. In general, all species presented low abundance in comparison to the preserved forest, indicating that mechanical control of shrubs (using tractors) had already had a negative effect on species. Moreover, some common species in these forests, such as Gymnocalycium schickendantzii and Echinopsis leucantha, were not recorded. For most cactus species, the herbicide would have minimal or no effect, since individuals were found alive and in good sanitary conditions. In a few individuals of Cereus forbesii and C. aethiops, the end of the stems was damaged. Some individuals of Stetsonia coryne and Cereus forbesii were found dead, but it is not clear whether the herbicide was the cause. Since pressure for more pastures for cattle is increasing worldwide, more studies on the effect of land use changes and the use of chemical products on cactus species in dry forests of the Americas are needed.

Fire and development influences on sagebrush community plant groups across a climate gradient in northern Nevada

AbstractThe sagebrush biome covers much of the western United States yet is at risk from ongoing disturbances. Physical disturbances such as fire often overcome the resistance of sagebrush communities to biological disturbances such as invasion by non‐native species, but the impact of burn severity or combined disturbance types on sagebrush community composition remains unclear. We examined the relationship between native functional groups and non‐native annual grass cover to the number of fires, burn severity, anthropogenic development, and vegetation treatments in northern Nevada, USA. We used Bureau of Land Management vegetation monitoring plots and existing climate, fire, and vegetation treatment databases to explore relationships using beta regression. After accounting for mean annual precipitation and temperature, and elevation, we quantified functional group mean cover related to levels of burn severity, numbers of fires, development, and vegetation treatments. Native herbaceous (grass and forb) groups were resilient to fire, but fire caused large declines in shrub and sagebrush cover. Non‐native annual grass cover was associated with higher burn severity and the first fire at a site. We did not find evidence that post‐fire restoration treatments were associated with increased native cover or decreased non‐native cover. However, shrub control and soil disturbing treatments (discing and chaining) were associated with decreased native perennial grass cover and increased non‐native annual grass cover. Functional groups displayed varying patterns related to anthropogenic development and fire. For example, development had a larger impact on non‐native cover at lower levels of burn severity, whereas forbs increased following fire only at lower levels of development. Although in some cases sagebrush communities showed resilience to disturbance, our results showed resistance to invasion by non‐native annual grasses can be overcome by combinations of disturbances at lower levels or by severe events.

Contribution to the knowledge on distribution in Hungary and habitat preferences of Gnaphosa modestior Kulczyński, 1897 a little-known spider species

Background and purpose: The aim of this review is to present current knowledge on the occurrence of a little-known gnaphosid species Gnaphosa modestior Kulczynski, 1897. Early it was mentioned as G. alpica species in Middle Europe. In this study, we reported the new occurrence of this species in Hungary and we examined of the effect of shrub control and mowing on this species abundance. Materials and methods: Our arachnological research was conducted in the Matra Mountains, the highest range of volcanic massin northern Hungary, between 2007 and 2016. Result and conclusion: We recorded 13 specimens from five habitats of the southern part of the Matra Mountains. This species can be found mainly in untreated shrubby habitats from April to June. In general, it can say that G. modestior is a stenochronous spider species which lives in habitats not influenced by human activities in the Matra Mountains. However, this attributes of species differ in some European countries.

Mitochondrial Genome Sequences of Diorhabda carinata and Diorhabda carinulata, Two Beetle Species Introduced to North America for Biological Control.

We announce the complete circularized mitochondrial genome assemblies of Diorhabda carinata and Diorhabda carinulata, beetle species introduced to North America for the biological control of invasive shrubs of the genus Tamarix L. (Tamaricaceae). The assemblies (16,232 and 16,298 bp, respectively) each comprise 13 protein-coding genes, 22 tRNAs, two rRNAs, and a noncoding region.

Recovery of the natural grassland in a degraded native forest of the Argentine Espinal through aerial chemical control of shrubs

The stability of the ecosystems is directly related to a high value of biodiversity and, in this sense, the anthropic effects have generated negative conditions on the natural pastures. The aim of this work was to evaluate the recovery of the natural grassland of a degraded native forest of the Argentine Spinal with shrubs by means of an aerial chemical control in a cattle system with rotary grazing of low instantaneous load. The study was carried out in the Protected Natural Area Reserve of Multiple Uses Estancia El Caraya located in the north central of Entre Rios, Argentina.16 evaluations were carried out (between 2012 and 2015) on the chemically treated sector with Picloram+2,4-D and on three sectors without treatment. In each evaluation, the vegetation cover, the floristic composition of the most representative forage species, and the plant biomass, were quantified. The results of this work show that the use of an aerial chemical control technique increases significantly, by 44%, the coverage and biomass of the forage species in the treated areas with respect to the control. Chemical control over shrubs persisted over time with considerable effectiveness during the years of evaluation. Likewise, the floristic composition of the herbaceous species did not present significant differences between treatments.

Removal pattern mitigates negative, short‐term effects of stepwise Russian olive eradication on breeding birds

AbstractInvasive species can have disastrous ecological consequences, and management is often required to control these invasions and mitigate the damage. Yet in many systems, biological invaders can serve critical ecological roles, particularly where they have been long‐established or effectively replaced functionally similar native species. In such cases, eradicating invasions can have unintended consequences on other components of the ecosystem, and potential control measures must be viewed within an ecosystem‐wide context to ensure they do not cause more harm than good. On the lower Snake River in eastern Washington, invasive Russian olive (Elaeagnus angustifolia) comprises 90% of the woody riparian vegetation in some areas. In this study, we experimentally removed half of the Russian olive from 0.5‐ha plots using three configuration patterns that varied in the amount of interspersion of remaining vegetation (n = 9 replicates) to evaluate the short‐term impact of a stepwise restoration strategy on breeding bird communities. We monitored plots for 5 yr and found that Russian olive removal on low interspersion treatments negatively affected occupancy rates for 50 of 52 species (96%) and significantly reduced richness by up to 2.41 (95% credible interval [CI] = 0.73, 4.14) species relative to control plots. These effects dampened with increasing interspersion, and occupancy rates of only 41 (79%) species decreased on high interspersion treatments, leading to non‐significant richness reductions of only 0.99 (95% CI = −0.70, 2.75) species. Given the dominance of Russian olive in this region, removing it eliminates critical habitat for birds that require woody structure for nesting and foraging. Thus, we caution managers to consider the potential short‐term negative impacts to the local fauna when planning invasive control efforts. However, we found that several riparian‐dependent species known to breed in the region were noticeably absent from our study plots, and short‐term losses in avian habitat may be tolerable where restoration of native vegetation supports greater diversity in the long term. In such restoration efforts, managers may be able to mitigate the negative effects of invasive shrub control by maintaining high interspersion among unmanipulated vegetation while waiting for native vegetation to re‐establish.

Vegetation responses and trade‐offs with soil‐related ecosystem services after shrub removal: A meta‐analysis

AbstractAimTo assess the sustainability of different shrub control practices (fire, mechanical, and chemical) based on their efficacy to control shrubs and their effects on multiple ecosystem service provisions, including possible trade‐off and/or synergy.MethodsUsing a meta‐analysis approach, this study synthesized results from global shrub removal experiments. Log response ratio (lnR) between the outcome of shrub removal and that of the untreated control was used to estimate proportional changes in soil and vegetation properties resulting from each shrub control practice.ResultsWhen forage provisioning is the only service considered, shrub removal could achieve this desirable outcome as indicated by increasing herbaceous biomass. However, observable decreases in litter, biological crust cover, and soil nutrients, as well as increases in bare soil indicated long‐term potential trade‐offs with other ecosystem services (e.g., erosion control service and nutrient cycling); the degree was influenced by different shrub control methods. Synergistic properties were probably limited to a short‐term boost of herb productivity resulting from short‐term increase in herb biomass and diversity as well as nutrient availability.ConclusionHuman‐induced drivers manifested in shrub control practices changed vegetation response. However, management also changed non‐targeted processes, generating potential reduction in several regulating ecosystem services. Continuous monitoring to assess landscape conditions should therefore become the key for adaptive management. Sustainable forage production should focus on strategies to maintain multiple ecosystem services because consideration of those services can lead to long‐term protection of the landscape and provide a broader range of environmental benefits.

Thirteen-year growth response of ponderosa pine plantations to dominant shrubs (Arctostaphylos and Ceanothus)

Thirteen-year growth response of ponderosa pine to various manipulations of understory vegetation was studied to determine if a threshold of understory cover can be established for plantation productivity and whether nitrogen-fixing Ceanothus species benefit plantation growth compared to non N-fixing Arctostaphylos species, given their ability to improve site fertility. Results showed that completely controlling competing vegetation increased plantation growth, as was universally expected, but the effects of partial shrub control on plantation performance was inconsistent. We did not find a benefit of nitrogen-fixing shrubs on tree growth, as young plantation growth was slightly better in the non N-fixing plots compared to the N-fixing plots due to differences in shrub cover. An understory cover threshold for tree growth was not observed. Due to the overriding effect of shrub competition, controlling herbaceous species had little effect on plantation growth even though it benefited tree seedling survival. A long-term value of N-fixing shrubs at these sites, if there is one, must be balanced by successful plantation establishment and rapid early growth.

Resilience of a ponderosa pine plantation to a backfiring operation during a mid-summer wildfire

The Mill Fire, which burned in north-western California during the summer of 2012, provided a unique research opportunity when firefighters implemented a backfiring operation to limit wildfire growth. This backfire was ignited and burned through research plots from a long-term study designed to determine the effects of tree density manipulation and shrub control on the growth and stand development of a ponderosa pine plantation. The objectives of this study were to examine the response of these 53-year-old trees to the backfire and to determine how the fire effects differed with plantation structure and composition. Measurements made 4 years post-fire showed that mortality rate was highly variable (from 0 to 100%) and did not relate to tree density, height of live crown, total basal area or shrub cover. Bole char height explained 65% of the variation in mortality rate. Fire appeared to spread primarily through the surface litter and killed a substantial proportion of the shrubs competing with the trees for water and nutrients. Importantly, post-fire tree growth was not significantly affected relative to pre-fire growth. A lack of negative effects of the fire on radial growth was possibly a result of release from inter-tree and shrub competition, which balanced any declines that might have been expected from bole injury or crown loss. Results from the present study demonstrate that ponderosa pine plantations could potentially be treated with managed fire (e.g. prescribed fire) without pretreatment (i.e. thinning, mastication), and still achieve good survival and improved resilience to wildfires burning under uncontrolled conditions.