Growth of Young Spruce Plantations in Interior British Columbia

Abstract

Ninety young plantations of Interior Spruce (Picea glauca (Moench) Voss or Picea engelmannii Parry or a natural hybrid of these species) in the Cariboo Forest Region, British Columbia were assessed for growth performance. Total and internode heights of 20 to 40 undamaged planted seedlings were measured in each plantation using 50 m2 plots to select sample seedlings.There were few striking differences in performance between stock types, site treatment types, season of planting, competing vegetation classes and ecological subzones. Good performance was found in part of the Sub-Boreal Spruce subzone, and poor performance was associated with either wet sites or dry sites. The performance of individual plants was highly variable and this could reduce potential plantation yields. Almost all plantations suffered a two year period of slow growth after planting. The one year old plug stock from styroblock containers grew more rapidly in the first year than bareroot stock types thus recovering from an initial size disadvantage. However, there was a marked decline in the second year growth of plus stock before a return to normal growth in the third year. The overall performance of small one year old seedlings suggest that size is over-emphasized in discussions of stock quality. The performance of all stock types was superior to recorded growth rates for natural seedlings of Interior Spruce.Suggestions are made for improving plantation performance and a simple growth performance guide is presented to help forest managers identify desirable, acceptable and unsatisfactory plantations of Interior Spruce.