Integrated Vegetation Management Research Articles

Listening to the response of bat and bush‐cricket communities to management regimes of powerline clearings

AbstractLinear transportation infrastructures (LTIs) are established drivers of habitat fragmentation and barrier effects. Yet, they represent an increasing surface of managed seminatural habitats where increased consideration of biodiversity outputs is needed in an era of global biodiversity decline. A combined effort by both scientists and stakeholders is, therefore, needed to evaluate the promises and limits of these alternatives so that they best achieve their conservation potential. Our study explores the effects of forest powerline clearings on biodiversity, as well as the potential benefits of integrated vegetation management (IVM) as alternatives to clear‐cuts. We recorded the acoustic activity at 35 pairs of forest/clearing stations in two forested regions of France in 2021. Our results suggest that powerline clearings represent increased movement opportunities for bats and, most particularly, edge‐foraging species. They also provide suitable habitats for bush‐cricket species, particularly species requiring thermophilic conditions. We detected no direct benefit from IVM on bat communities. However, bush‐cricket communities appeared richer, more acoustically active, and statistically different from adjacent forests in clearings favoring secondary vegetation compared with clear‐cut ones. This collaborative study provides data on understudied taxa in the context of LTIs and sheds light on conservation promises and limits associated with their management.

Комплексное управление лесной растительностью: этапы и перспективы развития

When enterprises of the timber industry complex form protective forest plantations along linear infrastructure facilities, the problem of subsequent spontaneous reproduction of tree and shrub vegetation arises, which leads to disorder in the territories of the above facilities and creates a threat to the safety of their operation. In many foreign countries, work to maintain the territories of linear infrastructure facilities in a standard state is carried out in strict accordance with certain methods of conceptual management of vegetation growth. At the same time, such management methods are practically unknown both to the domestic scientific community dealing with the issues of protective afforestation, and to those who make decisions on the need to influence unwanted trees and shrubs. The purpose of the study was to study and analyze systemic methods for managing unwanted tree and shrub vegetation growing on the territories of linear infrastructure facilities in order to improve the quality and efficiency of its removal, as well as to make recommendations for the proper maintenance of these territories. Cluster analysis of world research trends in forest vegetation management revealed 3 major areas associated with: a decrease or increase in species richness and diversity of vegetation, as well as the inadmissibility of its subsequent renewal; methods and means of influencing vegetation, including the benefits of vegetation management; ecological and aesthetic consequences of vegetation management, as well as public perception of the results of such management. The established principles for the application of the integrated vegetation management system (Integrated Vegetation Management: IVM), which is widespread in the world, are necessarily taken into account by organizations responsible for managing various protected zones and right-of-way. The most convenient for characterizing a selective approach to the management of unwanted vegetation growing in the territories of linear infrastructure facilities is the phrase «Integrated forest vegetation management». As the basic structure of the IVM system, the model proposed in 2005 by Nowak and Ballard is used, which provides for the implementation of a complete systems approach when influencing vegetation. It is inappropriate to combine in one step (the critical phase of this model) the monitoring of the potential effect of the impact on unwanted vegetation and the assessment of this impact. With further improvement of the IVM system, it is necessary to create a set of clearly defined and at the same time measurable indicators that fully reflect the achieved (or not achieved) effect from the impact on unwanted vegetation. It is shown that in order to introduce protective afforestation into domestic practice, IVM systems should not be a separate vegetation management tool, but a combination of management approaches, including not only the assessment of a plot of a linear infrastructure facility, but also subsequent control and determination of the quality of the normative maintenance of this plot.

Species Richness, Abundance, and Productivity of Birds Along a Powerline Right-of-way within a Forested Landscape, Northeastern United States

Utility rights-of-way (ROW) serve as nesting areas and maintain a high diversity of early successional birds. ROW incorporating wire zone–border zone and integrated vegetation management can be used as examples of early successional habitat management for bird conservation more generally in the Northeastern United States, given artificial disturbances not created solely for natural resource conservation comprise approximately 80% of early successional habitats. The objective of our study was to determine the effect of herbicide and mechanical vegetation management approaches on the abundance, species richness, and reproductive success of breeding bird species occupying an electric transmission line ROW in central Pennsylvania. The overall abundance of birds was significantly lower within the wire and border management zones, following initiation of a new vegetation management cycle at State Game Lands (SGL 33) than in the years prior to management. Sections of ROW with no border zones contained the lowest abundance and species richness of breeding birds compared to sections with borders prior to the initiation of a new management cycle. Sections of ROW with no border zones and mowing sections had the lowest bird abundance and species richness of all ROW sections at the onset of a new management cycle, and contained the lowest number of bird species displaying evidence of breeding, both prior to and at the beginning of management cycles. Sections of ROW managed using herbicides were comparable or more beneficial to bird communities in terms of abundance, species richness, indices of productivity, and nesting success than sections maintained via mechanical treatments (mowing and hand cutting), both at the end and beginning of management cycles within a forested landscape in the central Appalachian Mountains and surrounding forested regions in the northeastern United States.

Trade-Offs among Release Treatments in Jack Pine Plantations: Twenty-Five Year Responses

We assessed 27 indicators of plant diversity, stand yield and individual crop tree responses 25 years post-treatment to determine long-term trade-offs among conifer release treatments in boreal and sub-boreal forests. This research addresses the lack of longer-term data needed by forest managers to implement more integrated vegetation management programs, supporting more informed decisions about release treatment choice. Four treatments (untreated control, motor-manual brushsaw, single aerial spray, and complete competition removal) were established at two jack pine (Pinus banksiana Lamb.) sites in Ontario, Canada. Our results suggest that plant diversity and productivity in boreal jack pine forests are significantly influenced by vegetation management treatments. Overall, release treatments did not cause a loss of diversity but benefitted stand-scale yield and individual crop tree growth, with maximum benefits occurring in more intensive release treatments. However, none of the treatments maximized all 27 indicators studied; thus, forest managers are faced with trade-offs when choosing treatments. Research on longer term effects, ideally through at least one rotation, is essential to fully understand outcomes of different vegetation management on forest diversity, stand yield, and individual crop tree responses.

The Effects of Integrated Vegetation Management on Richness of Native Compatible Flowering Plants and abundance of Noncompatible Tree Species on a Right-of-Way in Central Pennsylvania, USA

We examined the effects of integrated vegetation management (IVM) and nonselective mechanical removal techniques (hand cutting and mowing) on the richness and abundance of native compatible flowering plants and noncompatible trees on an electric transmission line right-of-way in central Pennsylvania, USA. Our study focused on native flowering plants to help determine how different vegetation management techniques may affect native wildlife communities. We found no correlation between amount of herbicide applied and native flowering plant species richness or tree abundance. We found that the richness of native flowering plants did not differ between plots treated with an IVM herbicide approach and those that were mechanically treated (t = 1.06, df = 1, p = 0.31). However, mechanically treated plots had significantly higher abundance of trees than IVM plots (t = 3.10, df = 1, p = 0.009). We found that plots that were treated with herbicide mixtures that contained glyphosate in 2012 had lower native flowering plant species richness in 2016 than those treated with herbicide mixtures that did not contain glyphosate (t = −2.44, df = 1, p = 0.04). Our study indicates that long-term IVM approaches support native flowering plant species richness while limiting tree abundance under electric transmission line right-of-way. However, further study is needed to determine if the herbicide type and method (selective versus broadcast) of application affects species richness of native flowering plant communities.

Right of Way Integrated Vegetation Management: Essential to Keep the Us Economy Moving

Transportation and utility rights of way represent an often overlooked yet sizeable land mass across the U.S. that transects diverse topographies and ecosystems. These land uses, along with the necessary safety, drainage, and load bearing features, present unique challenges for vegetation management, especially on transportation rights of way. An integrated approach to vegetation management is essential to maintain the functionality of these corridors and should be part of the initial right of way design, but once constructed, mechanical and chemical control are the primary tactics to manage undesirable vegetation.

Increasing the conservation value of powerline corridors for wild bees through vegetation management: an experimental approach

Mounting evidence suggests declines in the abundance and diversity of wild bees. Increasing habitat that provides forage and nesting sites could boost struggling populations, particularly in urban, suburban and agricultural landscapes. The millions of acres beneath aerial electric transmission lines, sometimes referred to as easements or rights-of-way, must be kept free of tall-growing vegetation and hence have the potential to provide suitable habitat for many native species. Prior work has demonstrated that bee communities in easements managed using alternatives to episodic mowing were more diverse than in nearby open areas, however true control sites within the easements were unavailable. In order to compare vegetation management protocols, we conducted a two-year study which enabled us to directly compare transmission line easements in three locations currently undergoing Integrated Vegetation Management—a dynamic form of management involving spot removal and herbicide treatment of unwanted species (treatment) with nearby sites undergoing standard management protocols of yearly or biyearly mowing (control). Results show that treatment sites had significantly higher abundance and species richness than controls. Seasonal differences were pronounced, with the spring fauna most affected by differences in vegetation management. In addition, the older treatment sites house more social bees, more parasitic species and a more even distribution of bees across nesting guilds. Finally, we established that treatment sites had distinct bee communities, further increasing their value as sources for native bee populations in the landscape. Overall, the data clearly show the value of implementing alternative active vegetation management in the land under powerlines to achieve an increase in the abundance and diversity of wild bees.

Early Vegetation Responses to Eight Right-of-Way Integrated Vegetation Management Techniques in Northern Canada

Integrated vegetation management programs have successfully reduced the frequency and intensity of power line right-of-way management by promoting low-growing plant communities resistant to tree invasion. To examine whether these principles are transferable to northern ecosystems, researchers tested eight treatments at four sites in Yukon, Canada. Two herbicides, imazapyr and triclopyr, were applied by three methods, as well as a native grass seeding treatment and a mowing control. Vegetation cover was recorded prior to treatment and after one year along with herbicide damage assessments. Overall, treatments caused significant changes to vascular plant communities after one year. Short-term control of woody target species was greater in chemically-treated plots (66%–94%) than with mechanical methods (<55%). All treatments caused a minor reduction in non-target vegetation cover. In seeded plots, seedlings emerged but total non-target species cover was reduced by seedbed preparation. Triclopyr broadcast spray reduced non-target vegetation cover by <10%, but the common shrub, kinnickinnick (Arctostaphylos uva-ursi), was highly impacted. Selective application of triclopyr effectively controlled targets with minimal effects on non-target species. Imazapyr consistently caused more impacts to non-target plants than triclopyr. Both selective and non-selective imazapyr applications resulted in chlorosis, stunting, and deformity of shrubs and forbs one year after treatment. This suggests imazapyr can remain active in northern soils for at least 365 days as well as transfer to untreated plants. The range of sensitivities of boreal plant species to imazapyr and triclopyr and potential persistence in northern soils highlights the need for focused toxicity research in the North.

Plant Species Richness on a Transmission Right-of-Way in Southeastern Pennsylvania, U.S. Using Integrated Vegetation Management

The Green Lane Research and Demonstration Area, Montgomery County, Pennsylvania, U.S., has been studied each year since 1987, making this 21-year-old project extremely valuable as a source of information on the effects of mechanical and herbicidal maintenance on flora and fauna along an electric transmission right-of-way (ROW). In this article, our objective was to document plant species richness among treatment units and in relation to wire and border zones on the ROW. We noted the presence of plant species from late May through mid-August in 2005 and 2006 and observed 114 vascular plant species in the ten treatment units; 35 (31%) of these species were exotic. Twenty-seven (24%) species were widespread on the ROW and seven of these (26%) were exotic. The total number of species per unit ranged from 46 (40%) species in handcut units to 57 (50%) in stem–foliage spray units. Of the total number of species, 103 (90%) and 81 (71%) occurred in wire and border zones, respectively. The number of exotic species was higher in wire zones (33 [29%]) than in border zones (22 [19%]).

Techniques to control woody invasive plants in Indiana hardwood forests

At Purdue University we are investigating ways to control invasive woody species growing in oak ( Quercus L. [Fagaceae]) forests and other natural areas of Indiana. We have found several herbicides, and combinations of herbicides, that provide excellent control for a variety of woody invasive plant species when applied before, after, or in combination with mechanical removal. These control techniques offer a range of control options that are designed to be included in land managers’ integrated vegetation management (IVM) plans. Vegetation management that integrates the control and replacement of invasive plants with the establishment of favorable vegetation can help managers to efficiently achieve habitat management objectives and avoid future invasive plant problems. Natural resource managers may find these suggestions and experiences useful when developing their own IVM plans.

Control of Invasive Weeds with Prescribed Burning

Prescribed burning has primarily been used as a tool for the control of invasive late-season annual broadleaf and grass species, particularly yellow starthistle, medusahead, barb goatgrass, and several bromes. However, timely burning of a few invasive biennial broadleaves (e.g., sweetclover and garlic mustard), perennial grasses (e.g., bluegrasses and smooth brome), and woody species (e.g., brooms and Chinese tallow tree) also has been successful. In many cases, the effectiveness of prescribed burning can be enhanced when incorporated into an integrated vegetation management program. Although there are some excellent examples of successful use of prescribed burning for the control of invasive species, a limited number of species have been evaluated. In addition, few studies have measured the impact of prescribed burning on the long-term changes in plant communities, impacts to endangered plant species, effects on wildlife and insect populations, and alterations in soil biology, including nutrition, mycorrhizae, and hydrology. In this review, we evaluate the current state of knowledge on prescribed burning as a tool for invasive weed management.

Integrated Vegetation Management On An Electric Transmission Right-Of-Way In Southeastern Pennsylvania, U.S.

Integrated Vegetation Management (IVM) via the wire­border zone method has been used for the maintenance of vegetation along an electric utility transmission right-of-way (ROW) at the Green Lane Research and Demonstration Area, Montgomery County, Pennsylvania, U.S., since 1987. The wire­border zone method creates a forb­grass­short shrub cover type in wire zones and a tall shrub cover type in border zones. The Green Lane Research and Demonstration Area has been studied annually since 1987, which makes this 18-year-old project one of the longest continuous studies documenting the effects of mechanical and herbicidal maintenance on flora and fauna along an electric transmission ROW. In this paper, our objective is to present target (undesirable) tree density and cover-type development in response to IVM prior to the most recent treatment (June 1999) and 4 to 5 years after treatment. Excellent control of target trees was noted in 1999 in wire zones of mowing plus herbicide units; in contrast, tree control was poor in wire zones of mechanical units (mowing and handcut). Maximum tree height averaged 4.3 m (14 ft) and 4.9 m (16 ft) in wire and border zones, respectively. Immediately prior to the 1999 treatment of the Green Lane ROW, cover types in wire zones of herbicidal units (mowing plus herbicide, stem­foliage spray, and foliage spray) were classified as shrub­forb­grass­tree, whereas types in border zones of these units were tree­shrub­forb. Both wire and border zones of mechanical units were considered tree­shrub­forb cover type. The overall density of target trees increased 7.3% and 26.4% in wire zones and border zones, respectively, in 2004 compared to 2003. From 1999­2004, the most common target tree species on the Green Lane ROW was white ash (Fraxinus americana). In both 2003 and 2004, shrubs and forbs were the most important cover types in wire zones of all treatment units; grass cover type, however, was important in wire zones of five of the ten units. IVM of a ROW is a "tree resistant" but not a "tree proof " means of reducing tree invasion. Competition with existing plants and wildlife predation on tree seeds on a ROW managed via the wire­border zone method keeps tree invasion to a minimum. Thus, over the years since 1987, IVM and the wire­border zone method of ROW maintenance have increased the time between treatment cycles, thereby reducing labor and chemical costs for ROW maintenance.

Plant Species Richness On An Electric Transmission Right-Of-Way Using Integrated Vegetation Management

The State Game Lands (SGL) 33 Research and Demonstration Area, Centre County, Pennsylvania, U.S., has been studied each year since 1953, making this 52-year old project extremely valuable as a source of information on the effects of mechanical and herbicidal maintenance on flora and fauna along an electric transmission right-of-way (ROW). A desired objective of integrated vegetation management on the SGL 33 Research and Demonstration Area is to create a diversity of plant species. In this paper, our objective was to document plant species richness among treatment units and in relation to wire and border zones on the SGL 33 Research and Demonstration Area. We noted the presence of plant species from late May through mid-August in both 2003 and 2004 and observed 125 vascular plant species in the 15 treatment units. The total number of species per unit ranged from a low of 35 species in a mowing unit to a high of 63 species in a basal low-volume spray unit. Of the total number of plant species found on the right-of-way, 95 (76%) and 110 (88%) occurred in wire and border zones, respectively. In wire zones, the average number of plant species ranged from 31 in mowing units to 41 in stem­foliage spray units. In border zones, the average number of plant species varied from a low of 34 in mowing units to a high of 41 in handcut units. The proportion of exotic species did not vary appreciably between wire and border zones (19% and 22% of total, respectively) on the ROW. However, the three units adjacent to unpaved state forest roads with high rates vehicular traffic not only had the highest number of total species in the unit (55 to 63 species) but also the highest number of exotic species (13 to 16 species). Hence, vehicular traffic and roadside management may be responsible in part for the invasion of seeds or other means of plant dispersal to these units. Because units relatively isolated from state forest roads tended to have fewer exotic species, these sections of the ROW can serve as refugia for native flora.

A Framework For Applying Integrated Vegetation Management On Rights-Of-Way

Integrated Vegetation Management, or IVM, is purportedly being used by many right-of-way management organizations across the United States. In many cases, IVM is just a name applied to old management approaches. Yet IVM is more than just a name. It is an in-depth and sophisticated system of information gathering, planning, implementing, reviewing, and improving vegetation management treatments. IVM is used to understand, justify, choose among, selectively apply, and monitor different types of treatments, with an overall goal of eliciting site-specific, ecosystem-sensitive, economically sensible, and socially responsible treatment effects that lead to refined achievement of management objectives. We propose a six-step system to IVM that can act as a framework of activities to aid managers and other related stakeholders in communicating, organizing, and conducting IVM business. Each step produces information that must be integrated into the management system. Our six-step system is consistent with Integrated Pest Management and other IVM-like systems developed in forestry and agriculture. We present an IVM system with some unique perspectives and ideas from the literature, and incorporate information from and experience with the electric utility industry.

An integrated management strategy for the control of purple loosestrife Lythrum salicaria L. (Lythraceae) in the Netley-Libau Marsh, southern Manitoba

We evaluated the eVectiveness of an integrated vegetation management strategy (IVM) for the management of purple loosestrife (Lythrum salicaria) by comparing the performance of herbicides alone (glyphosate and triclopyr amine), a biological control agent (Galerucella calmariensis) alone, and herbicides integrated with the biological control agent. The study was conducted from 1996 to 1998 within Weld-cages placed in a 2-ha stand of purple loosestrife located in southern Manitoba. Using a randomized complete block design, each treatment was replicated three times. Herbicides were applied in the summer of 1996 while G. calmariensis were released at either low-densities (12 adults) or high-densities (24 adults) in 1997. We measured performance using data on Wnal stem heights, terminal spike length, the number of Xowering spikes, and the number of seed capsules in each year and the total number of all stems at the end of each year. Integrated treatments were found to cause signiWcant reductions in the mean number of purple loosestrife stems. The G. calmariensis alone treatments resulted in no signiWcant change in mean stem densities; however, herbivory reduced mean stem heights by almost 70%. Mean stem densities of purple loosestrife increased in the herbicide alone treatments when compared to pretreatment levels. Results indicated that an IVM strategy using herbicides integrated with G. calmariensis outperformed herbicide alone treatments and G. calmariensis alone. While further open-Weld investigations are required, these results have important management implications.  2004 Elsevier Inc. All rights reserved.

Integrated Vegetation Management On An Electric Transmission Right-Of-Way In Pennsylvania, U.S.

Integrated vegetation management (IVM) has been used for the maintenance of vegetation along an electric utility transmission right-of-way (ROW) at the State Game Lands (SGL 33) Research and Demonstration Area, Centre County, Pennsylvania, U.S., since 1987. In addition, the wire­border zone method was implemented on the ROW in 1987. The wire­border zone method results in forb­grass­shrub cover types in wire zones and shrub cover types in border zones. The SGL 33 Research and Demonstration Area has been studied since 1953, which makes this 51-year-old project the longest continuous study documenting the effects of mechanical and herbicidal maintenance on flora and fauna along an electric transmission ROW. In this paper, our objective is to present target (undesirable) tree density and cover-type development in response to IVM prior to the most recent treatment (2000) and 2 to 3 years after treatment. Results were compared to those obtained from the late 1980s and 1990s. For all units combined (except handcut) in 1999, average target tree densities prior to treatment were 288 trees/ha (117 trees/ac) in wire zones and 759 trees/ha (307 trees/ac) in border zones. Excellent control of target tree density [62 to 124 trees/ha (25 to 50 trees/ac)] was noted in wire zones of mowing plus herbicide, stem­foliage spray, and foliage spray units; moderate control [371 to 680 trees/ha (150 to 275 trees/ac)] was observed in low-volume basal spray, high-volume basal spray units, and mowing units; and poor control (4,818 trees/ha [1,951 trees/ac]) was found in the handcut unit. In 2003, the density of target trees in all treatment units combined was 1,544 trees/ha (625 tree/ac) in wire zones and 1,594 trees/ha (645 trees/ac) in border zones. If the handcut unit was omitted from the calculations, then only 340 target trees/ha (138 trees/ac) in wire zones and 501 trees/ha (203 trees/ac) in border zones were present. IVM of a ROW is not a "tree-proof" but rather a "tree-resistant" means of reducing tree invasion. Competition with existing plants and wildlife predation on tree seeds on a ROW managed via the wire­border zone method minimized but did not eliminate tree invasion. Since 1987, IVM and the wire­border zone method of ROW maintenance has increased the time between treatment cycles, thereby reducing labor and chemical costs at the SGL 33 Research and Demonstration Area.

Integration of visual quality considerations in development of Israeli vegetation management policy.

This article deals with the visual quality of Mediterranean vegetation groups in northern Israel, the public's preference of these groups as a visual resource, and the policy options for their management. The study is based on a sample of 44 Mediterranean vegetation groups and three population groups of local residents, who were interviewed using a questionnaire and photographs of the vegetation groups. The results of the research showed that plant classification methods based on flora composition, habitat, and external appearance were found to be suitable for visual plant classification and for the evaluation of visual preference of vegetation groups by the interviewed public. The vegetation groups of planted pine forests and olive groves, characterizing a cultured vegetation landscape, were preferred over typical Mediterranean landscapes such as scrub and grassed scrub. The researchers noted a marked difference between the two products of vegetation management policy, one that proposes the conservation and restoration of the variety of native Mediterranean vegetation landscape, and a second that advanced the development of the cultured landscape of planted olive groves and pines forests, which were highly preferred by the public. The authors suggested the development of an integrated vegetation management policy that would combine both needs and thus reduce the gap between the policy proposed by planners and the local population's visual preference.

Vector competition analysis: a new approach for evaluating vegetation control methods in young black spruce plantations

This paper reports on a new graphical analysis technique that facilitates screening alternative strategies for crop management in programs of integrated vegetation management in young forest plantations. The responsiveness of black spruce seedlings to three vegetation management measures (herbicide application, fertilization and seedling nutrient loading) on two contrasting site types (Hardwood [ST 10] and Feathermoss [ST 4]) located in northern Ontario, were compared and evaluated using vector competition analysis. The approach is based on vector diagnosis and regression analysis that compare growth and nutritional interactions between crop and non-crop plants competing for the same growth resources. Response parameters are examined in a bivariate model depicting vectors of changing biomass production or nutrient uptake relative to competition-free treatments. Although herbicide application reduced non-crop vegetation on both sites, it accelerated tree growth and nutrient uptake only in the herb-rich Hardwood site, but had no effect on seedlings in the Feathermoss site. Fertilization stimulated vegetation growth in the competitive Hardwood site causing seedling suppression, but stimulated both tree and non-crop vegetation growth in the Feathermoss site because of weaker competition. Preplant nutrient loading improved seedling growth and nutrition reducing competition of neighboring weeds. Vector competition analysis facilitated interpretation of plant interactive relationships and identification of limiting factors. Advantages over traditional competition indices are that both growth and nutrition parameters, as well as crop and non-crop responses are quantitatively and systematically evaluated, and that simultaneous comparisons simplified screening of the most effective treatments and sites for possible vegetation control. Key words: Competition indices, treatment screening, nutrient loading, fertilization, herbicide

Interaction of vegetation with the LUL surface railway system: M. J. Gellatley, B. T. McGinnity, D. H. Barker & W. J. Rankin, in: Vegetation and slopes: stabilisation, protection and ecology. Proc. conference, Oxford, 1994, ed. D.H. Barker, (Thomas Telford, for ICE), 1995, pp 60–71

The London Underground Limited (LUL) public transportation system comprises some 400 route kilometres of track with just in excess of half of this forming the surface section of the system. Vegetation performs an important engineering function on the surface railway in providing shelter from the effects of wind and snow, in maintaining and enhancing the stability of earthwork slopes and in providing visual and acoustic screening. Vegetation growth also has important implications for the local ecology and wider environment. This has been recognised and recently LUL have taken steps towards defining and implementing integrated vegetation management standards. This paper provides an assessment of the interaction of vegetation with LUL earthworks slopes and structures within the surface railway corridor and reports on current vegetation maintenance standards and strategies. For the covering abstract see ITRD E116612.

Integrated vegetation management in California – advances and future

A study on alternatives for releasing young conifer plantations on National Forests in northern and central California was started in 1980, and enlarged to include State of California, Bureau of Land Management, and private industry lands. Forty studies involving chemical, manual, mechanical, mulch, and animal treatments have been established and their effect on the survival and growth of conifer seedlings is being quantified. Plant diversity and succession on both treated and untreated sites are being recorded. The oldest study has had 10 growing seasons since the first treatments were applied. To release conifer seedlings, a treatment radius of at least 1.5 meters is required; smaller radii do not provide enough site resources for acceptable growth. Diameter, rather than height, is the best indicator of release. Some non-phenoxy chemicals show promise for good control of competing vegetation. Mechanical release requires additional treatments to effectively control shrubs. Mulching has given limited results to date. Manual treatments, if applied to non-sprouting and nonrhizomatous plants soon after planting, and usually more than once, provide adequate control of competing vegetation, but are costly.