Fig. 2

Variation in root mean square error (RMSE) for parametric models (black open triangles) and non-parametric models using the most similar neighbour with k = 1 (red open circles) and optimised k (pink crosses) and k-nearest neighbour (k-NN) using k = 1 (black filled squares) and k-NN using an optimised value of k (filled cyan circles) for models that a do not include age and b include age. Note that model precision is not given for use of LiDAR without age (panel a) as these models are not feasible