Problem:

As more improved planting stock such as clones and genetically improved seedlings are introduced to the market it is important to properly understand the benefits of each production type. Various breeding programmes make claims around performance of their seedlots but there is a shortage of literature around the performance of these production types in a plantation setting for most production species.

Approach:

One seedling, two cuttings, and 7 clonal varieties were compared in a plantation setting on a single site. The stand was measured via five permanent sample plots (PSPs) per seedlot. The seedlots were categorised by material production type and compared using pair-wise analysis to find statistically significant differences. The seedlots were then compared individually to find any intramaterial differences. Available aerial LIDAR was then used to estimate tree height for the total seedlot area and establish whether this was an accurate estimate. Average LIDAR height was then used to estimate tree height for each of the five PSPs to establish whether this would improve the prediction of heights and permit its use for large-scale evaluation of genetic material.

Results:

Categorising seedlots by material type there was no statistical difference for height performance but there was for DBH and basal area. Clones and open-pollinated seedlots showed superior performance over controlled-pollinated material, but not different from each other. Clones showed reduced height variability over non-clones. DBH and basal area variability was also reduced but the difference was only statistically significant versus open-pollinated seedlots. Comparing seedlots individually there was large variation in performance and variability within material types, with clones showing some superiority and non-clones inconsistent improvements.

The LIDAR tree height model for whole seedlot area showed to be a significant predictor average PSP height but poorly predicted CV. Predicting PSP area provided with LIDAR improved correlations over whole stand predictions for both values.

Implications:

The performance superiority for clones over other production types in this trial is not as pronounced as previously suspected. Clones do, however, provide a more uniform crop. The LIDAR tree height model could be used for further analysis but not for height variability without further improvement. Result validity was, however, reduced by the lack of trial replication and randomisation. This is the key limitation and makes guaranteeing improvements are due to improved genetics (not environment) problematic.