The majority of forestland in the US is privately owned and the app is designed to assist these landowners – who may only have a few dozen, or a few hundred mature hardwood trees – to understand their value before hiring a professional forester.
The app, which is now available from the Apple App Store, currently has one function: measuring a tree’s diameter. It does this using the multiple camera lenses on the back of an iPhone. Developing this type of app presented a unique challenge to Professor Zhang’s graduate students, Wang Xiang and Zhiheng Yin. They needed to figure out a way to filter out foliage and background clutter. Additionally, they needed to identify the standardised height at which tree diameter is measured – about 4.5ft above the ground – and be able to do all this with high accuracy and security, at a low computational cost, to function on a phone.
The next feature, which the team hopes to have ready soon, will be measuring merchantable and total tree height, which, in conjunction with diameter, will allow an estimation of volume. Knowing a tree’s volume, or biomass, will make it possible to estimate how much carbon it can sequester. This could be a valuable way of assessing a plot of land’s value and particularly how management practices might affect the environment. Another future feature will assess tree grade – a rating used by foresters to assess value, which includes information about how straight the tree is and the number of knots or other defects.
