Modeling early plantation performance: Identification of critical factors

Abstract

Four‐year data on spring outplanted black spruce (Picea mariana (Mill.) B.S.P.), white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb.) were subjected to stepwise multiple linear regression analysis with mixed models containing both continuous and categorical variables. Several treatments had been imposed on two provenances of seedlings of each species, including machine‐ and hand‐planting in furrows, or hand‐planting on untreated ground; and heavy, light, or no NPK fertilization immediately after planting. Furrow depth, initial height, vertically, and direction of lean of each newly planted tree, and first‐ through fourth‐year survival, growth, and condition were recorded. For each species, survival and total height equations are tabulated to show the proportion of variability explained by qualitative variables (site and stock factors), planting stock characters, and plantation age. Age accounted for 13–92% of the total variability in survival and growth. Both planting without site preparation and heavy fertilization were significantly detrimental to survival and growth, but light fertilization was beneficial when significant. Provenance had little or no influence on results.

Key words:

• Picea mariana
• Picea glauca
• Pinus banksiana
• plantation establishment
• plantation performance
• categorical variables
• regression modeling
• machine planting
• hand planting
• fertilization