The aims of landscaping are to enhance the track or road and the surrounding areas, protect nearby river banks, control water and wind erosion on embankments to improve structural stability, improve air quality and provide greater user comfort.
When possible, and depending on the particular site, the scope of landscaping work can be extended to include the provision of other spaces. Infrastructures are built for public use such as children’s playgrounds, rest zones and urban art areas, etc.
Landscaping around road and rail infrastructures is of extreme importance and high on the list of IP priorities.
Over the approximately 16,000 kilometers of roads and tracks under IP’s direct management, many thousands of trees can be seen. In addition to their important environmental role, these trees also contribute to the performance of the infrastructure. However, they also represent a challenge in terms of road and rail infrastructure maintenance, as their presence, particularly when they are degraded, brings numerous risks to users.
When trees are in a state of balance they protect soil from erosion, improve air quality, help regulate temperatures and water retention and provide a barrier against the wind, thus contributing to the resilience of structures against weather phenomena.
Trees also help in the integration of roads and tracks into a balanced landscape and improve the comfort of those using the infrastructures and surrounding areas. They also frequently allow green corridors to be created which are highly important for the conservation of fauna.
However, the problems caused by trees next to roads and railway tracks are varied and frequent, such as falling branches and leaves, encroachment of foliage onto traffic paths, poor signage visibility and safety of overhead lines, vehicles hitting trees and damage to structures caused by root growth.
To safeguard against these situations, IP conducts a range of actions to inspect trees on road and rail infrastructure so as to identify any issues which could present a risk to traffic or the structures themselves, as well as any corrective measures required.
The problems most frequently seen are caused by trees which are not suitable for the place where they are planted due to changes in the space over time or poor initial choices, or plant health issues caused by ageing, degradation of site conditions or pests or illness.
Depending on the problem encountered, and the interest in keeping a specific series of trees or an individual tree at a specific site, action is taken to either resolve or mitigate the issue.
Trees are often just pruned to improve traffic movement and road or track safety, maintaining them in the same place. Sometimes though it is necessary to cut down the trees when it proves impossible to allow them to remain or when they are weak or affected by pests or illness, in which case they have to be removed.
When site conditions allow, the felled trees are replaced by other species which are better suited to the specific soil and climate conditions and better sized for the space itself.
However, IP is required to fell many trees in places where it is not possible to replace them, and as such we plant other trees in different locations, sometimes away from infrastructure. IP prefers to work in partnership with local municipalities and other public entities and associations, which very often brings greater success in reforesting actions.
Work by IP to defend the forest against fires
In 2004, the first Decree-Law was approved which provided for a national forest fire prevention system and which focused specifically on planning and prevention. Since then, this legislation has been amended several times and fire prevention actions throughout the road and rail network have become increasingly important.
IP is currently required by law to be represented on all Municipal Commissions to Defend the Forest against Fire (PMDFCI), created for the 278 municipalities in mainland Portugal, as well as on the 18 district commissions (DFCI). IP contributes in the definition of Fuel Management Corridors in our network and we report the actions we undertake in this regard to the commissions.
Work to be carried out in the Fuel Management Corridors is duly specified and set out in network conservation/maintenance contracts, or in specific contracts for vegetation management.
Use of herbicides
Controlling vegetation growth near roads and railway tracks is vital for safety. Control is mainly achieved by periodic cutting. However, in some situations this approach is insufficient and herbicides are required to maintain roads and railway tracks safe. Such situations include:
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Areas above tracks as all areas with ballast must remain free of vegetation as any growth of weeds or grass can alter the characteristics of the ballast and affect safety;
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In some areas adjacent to lines or roads, with the aim of containing the development of vegetation to improve safety conditions and/or ensure compliance with fuel management criteria, with particular emphasis on areas infested with invasive species.
In all of these activities, IP requires sub-contractors to use herbicides which are approved for use on road and rail, and they must also comply with all safety measures as provided for in legislation.
With regard to the treatment of areas adjacent to roads and railway lines, IP has experimented with a number of alternatives, and conservation and maintenance contracts now include provisions for activities which aim to replace herbicides with thermal techniques and other specific measures to control invasive species without the use of chemicals. These measures include pulling up and debarking vegetation, or minimizing herbicide use by mean of direct injection.
