D s -optimal designs for Kozak's tree taper model

In this work, we study D s -optimal design for Kozak's tree taper model. The approximate D s -optimal designs are found invariant to tree size and hence create a ground to construct a general replication-free D s -optimal design. Even though the designs are found not to be dependent on the parameter value p of the Kozak's model, they are sensitive to the s ×1 subset parameter vector values of the model. The 12 points replication-free design (with 91% efficiency) suggested in this study is believed to reduce cost and time for data collection and more importantly to precisely estimate the subset parameters of interest.