Highways England Natural Capital Valuation

Treeconomics undertook a Natural Capital Valuation of Highways England’s ‘soft estate’. This project comprised an environmental and economic benefits assessment of the trees, shrubs, soils and grasses in ‘Area 1’. This was followed by an ecosystem services (ES) review, to establish what other ES could be measured, quantified and valued, as well as a concept design cost/benefit calculator. The review and tool has been used by Kier Highways designers to ensure that infrastructure projects result in no net loss of ES.

Following the success of this project, Highways England and Kier commissioned Treeconomics to further develop the concept design tool through improvements to usability and format, publishing the full i-Tree Design tool as a web-based application.

The i-Tree Design tool allows designers to select trees on site due for removal as part of development projects (such as road widening schemes) and to include details of new planting. It allows designers to calculate the impact of new planting in terms of mitigation for losses of trees and other landscape features. The tool also provides a break even point in years showing when, and if, new planting would mitigate for benefits foregone as part of the proposed plans.

This is an important step; for the first time, designers can quickly amend planting plans with alternative species and numbers to ensure projects result in no net loss of ES.