BIM for Arboriculture – the Legend of 3D

In 2011 the UK Government published the Government Construction Strategy which included the statement that the ‘…government will require [on centrally-procured public projects] fully collaborative 3D Building Information Modelling (BIM) (with all project and asset information, documentation and data being electronic) as a minimum by 2016’ (source: www.designingbuildings.co.uk/wiki/Building_information_modelling_BIM).

As we start a new decade, we see many design and construction projects still delivered without the use of BIM and, while the elements of design that generally deliver rigid forms (architecture, engineering, etc.) have established processes and software for producing 3D models, those of us responsible for incorporating the natural world into design (Arboriculturists, Landscape Architects, etc.) are still working with the software developers to produce packages that efficiently and accurately represent natural forms in three dimensions. And meanwhile technological advances in hardware and software are leapfrogging the established technologies…but more on this later.

To many arboriculturist practices, in a sector where 94.2% of companies are small or micro, the term “BIM” and its association with 3D modelling has had connotations of a level of technological infrastructure that can only be achieved by the multi-national architectural practices.

However, arboriculture has been an early adopter of many mapping technologies, including GPS and GIS, and we should not be over-awed by BIM, or as it is increasingly referred to these days, Digital Practice.

BIM, as it was first conceived, comprised four levels intended as a method for all disciplines in the design and construction teams to share information and collaborate on the design.

The levels are defined as (www.designingbuildings.co.uk/wiki/Home):

• Level 0: Unmanaged CAD (Computer Aided Design).
• Level 1: Managed CAD in 2D or 3D.
• Level 2: Managed 3D environment with data attached, but created in separate discipline models.
• Level 3: Single, online, project model with construction sequencing, cost and life-cycle management information.

However, these levels are being done away with and being replaced with the UK BIM Framework with ISO standards being developed by UK BIM Alliance and partners.

I would expect many arboricultural practices are currently regularly producing plans in line with Level 1 and those of us who work with relational databases integrated with GIS are no doubt working with modelling costs over time in a way that delivers some of the elements required for Level 3.

Working collaboratively with other disciplines on a consolidated CAD plan is something that many consultants will be doing regularly.

From our experience of GIS most of us are familiar with locating an object (normally a tree) within the Ordnance Survey’s coordinate system.

So many of the principles and objectives of BIM / Digital Practice are actually familiar to us in arboriculture.

There are some big gaps to be bridged in our sector’s practice, in the software that supports it and in our integration with design teams. We need to be engaged with the development of Digital Practice so that it can best support the value that expert tree knowledge and advice brings to an integrated design process.

Our team at Treework Environmental Practice, have been working with these concepts for many years, we are aware that there is a need for expert tree advice in any design team dealing with a project where existing and / or new trees are material to the decisions about design, planning and / or construction. As the tree experts on the team we need to communicate, collaborate and share information in the format that best suits the team and the project.

For us this starts with how we collect the information; we have developed MyTrees as a long term tree management tool that records the tree information spatially in a GIS, referenced to the site plans and designs, records management activities with priorities that generate future dates and budgets and retains history of changes. MyTrees exports to standard formats that can be easily shared with others.

Although MyTrees does not generate 3D models, the key information for generating 3D models of trees is recorded in MyTrees.

The 4D data of maintenance budgets (as described above) and changes in the value over future years are also recorded in MyTrees.

The 4D element is crucial when dealing with trees, landscape and other elements of green infrastructure. For trees, the Capital Asset Value (CAVAT) and the ecosystem services values (as generated by i-Tree) tend to increase as the tree grows. As such, trees and green infrastructure are unique in the field of design and construction in that they are accruing assets to the scheme.

These values are increasingly recognised and promoted for their contribution to targets such as being nationally carbon neutral by 2050 and emerging policy on biodiversity net gain. So modelling the growth of trees and of the benefits that they provide over time is essential for decision making. The autumn 2019 edition of the Landscape Institute Journal has an interesting article titled “How to Make the most of BIM to Reduce Carbon emissions” you can find this edition at: https://www.landscapeinstitute.org/journal/landscape-journal-autumn-2019-climate-emergency-edition/).

Three-dimensional modelling of trees is more difficult, in some ways, than 4D modelling. There are so many variables that are essential for generating useful and realistic information from the 3D tree forms. For instance, to truly understand the shade impacts of a tree we need to know how dense it is and whether it loses its leaves in the winter. If the same tree is pruned, its canopy may become denser. Additionally, there currently is currently no software that reliably and efficiently generates all of the 3D parameters of a tree population from the data that is collected; so it takes time to produce each tree individually. Very detailed 3D models take up a lot of memory, both processing and storage and so limit the shareability of the information.

Our team works with the standard software’s to produce excellent 3D models of trees to inform on above and below ground clashes, sunlight, daylight, shade and shadow. We also collect the data via point cloud scanning and use this to generate our models.

We find that it provides excellent opportunities to work with the team to identify clashes, resolve problems and helps the team to visualise how the design and the practicalities of construction interact with the trees.

Our work with veteran trees has given rise to some unusual applications of these 3D models including modelling the likely shade impact of a building on an ancient tree and informing an engineering assessment of the likely effectiveness and possible detrimental affects of applying a prop to a historically important tree.

Yet while we grapple with the challenges of 3D modelling of trees, the technology is leaping ahead and becoming increasingly available with above and below ground 3D scanning, on line portals such as Tridify where the data can be held and shared without the need to take up local processing or storage, drones and services such as Vu.City and Ordnance Survey collecting 3D information by regular flyovers with multi-spectrum cameras and lidar, generating local and national 3D models which are rented to users.

The drivers for developments in this area are as varied as Virtual Reality, tools for designing environments for gaming, advances in the automated car industry, automation and Artificial Intelligence.

It is often difficult for individual companies to know when is the ‘right time’ to get on ‘the wave’; will you be too early and the technology you invest in superseded by cheaper technology that enables your competitors to leapfrog your position or will you be too late and have to catch up with the pioneers?

It is essential that the tree and landscape sectors engage with and inform the development of Digital Practice and the technologies that support it.

To support the arboricultural sector’s engagement with Digital Practice, we are excited to be part of the Arboricultural Digital Practice Group (under the umbrella of the Landscape Institute’s Digital Practice Group). Our mission is to:

To develop standards for recording, presenting, interacting with and sharing tree information within the context of Building Information Modelling (BIM)

To share information and engage the arboricultural sector in the process and outcomes.

To coordinate and engage with associated sectors with the aim of aligning our outcomes with theirs and engaging them with our sector.

We are currently collecting base line data to inform how we proceed so it would be very helpful if you could please contribute via this link: www.surveymonkey.co.uk/r/9Q2HTQZ.

We also have a fledgling LinkedIn group at https://www.linkedin.com/groups/8605958 , please join us to be kept up to date.

We are planning a workshop with software developers in April, watch this space for updates.

If you would like to be involved in the Arboricultural Digital Practice Group, please email us at digitalarb@landscapeinstitute.org.

This is an exciting time at the interface of technology and the environment, at the start of a new decade there is much for us all to do and great opportunities to influence for positive development.