Campelo, F., Vieira, J., Battipaglia, G. et al. Which matters most for the
formation of intra-annual density fluctuations in Pinus pinaster: age or
size? Trees (2015) 29: 237. doi:10.1007/s00468-014-1108-9
# NOT RUN {data('example_iadf')
data('example_rwl')
model <- campelo_chapman(campelo_freq(example_iadf, example_rwl))
campelo_index(example_iadf, example_rwl, model)
# }