Modelling the effects of nursery and site management on the early performance of Picea sitchensis (Bong.) Carr

This study examined the potential of mathematical modelling, following initial statistical analyses, to describe, summarise, and integrate information from nursery and establishment experiments. It is part of a larger study evaluating this general approach as a means of bringing together information on a wide range of establishment techniques and site factors which is extensive but at present largely inaccessible to managers. Twenty six establishment experiments in NE England were screened. Eight experiments were identified for mathematical modelling on the basis of having at least 3 assessments between planting and canopy closure, replicated designs, and combinations of nursery and site treatments. Nursery spacing, nursery fertilisation, plant height, plant diameter, and handling had insignificant or inconsistent effects on performance and were not modelled. Significant factors in the survival model were cultivation of the planting site, which increased survival; and stock type (transplants had poorer survival than undercut and wrenched seedlings). Significant factors in the height model were the method of cultivation used at the planting site (screefing < no cultivation < ploughing or mounding); stock type (transplants had poorer growth than undercuts); and presence of Calluna vulgaris which was associated with decreased growth. The relationships between plant performance over the first 6 years after outplanting and both nursery and site practices, including their interactions, were adequately described by simple mathematical equations. These mathematical descriptions could in future be incorporated into computer software thereby allowing managers, who are faced with increasingly demanding targets for efficient establishment, to weigh up the resource implications of various establishment techniques against the predicted gain in survival and height.[PUBLICATION ABSTRACT]