Assessment of curly birch introduction prospects

Abstract

We introduce an analysis of the experience of curly birch introductions accumulated in Russia and abroad, from which the main means and methods of evaluating introduction prospects were derived. It follows from this analysis that the most important and commonly used approaches and criteria are: comparison of the edaphic and climatic conditions in the prospective introduction site and the location from which the source material is taken (climate analogues method), assessment of the origin and biological characteristics of the source material, assessment of the composition of stand-forming tree species and their companion species in the prospective introduction site. In addition, we suggest the “distance method”, providing information about the distance from the species range boundary to the prospective introduction site, and about the distance over which curly birch has been moved for introduction before relative to the “averaged” distance. The importance of cultural operations, stocking rate and density of the planted trees for the expression of “figured grain” and “figure intensity” features in wood is highlighted. It is concluded that although curly birch has quite high ecological plasticity and, accordingly, a high introduction potential, the prospects for its introduction should be assessed using a widest possible set of indirect criteria and indicators, which will collectively yield a more probable future estimate of the introduction outcome, and generate a premise for improving its efficiency. The lack of the said integrated approach to evaluating the prospects of introduction is a key reason for its underperformance, notably reducing the chances of successfully dealing with the tasks of gene pool preservation and augmented reproduction of this unique member of the forest tree flora by means of introductions