1 Introduction

2 Materials and Methods  
2.1 Data of the Forest Condition Survey  
2.2 Spatio-temporal Model for Mean Defoliation  
2.3 Trend Estimation  
2.4 Simulation Study for the Grid Examination  

3 Results  
3.1 Age-adjusted Spatio-temporal Trend of Defoliation  
3.2 Grid Examination  

4 Discussion  
4.1 Spatio-temporal Modelling of Defoliation  
4.2 Model-based Approach for Grid Examination  

5 Conclusions