Estimation of boreal forest LAI in winter conditions: Test of a new method using wide optics airborne images

A new simple airborne method based on wide optics camera was developed for leaf area index (LAI) estimation in coniferous forests. The measurements are carried out in winter, when the forest floor is completely snow covered and thus acts as a light background for the images analysis. The photos are taken automatically and stored on a laptop during the flights. The R² value of the linear regression of the airborne and ground based LAI measurements was 0.90 for all plots. Despite of the unfavourable weather conditions the average difference of the ground based and airborne regression based LAI estimates was 0.16 and in 80% of cases it was smaller than 0.28. The standard deviation of the plotwise ground based LAI values was of the same order.