Espacement Trials in the BC Interior (EP 964)

On this page:

• Introduction
• Objectives
• Treatments
• Publications

Introduction

Beginning in 1986, a series of long-term experiments were established by the B.C. Ministry of Forests, Forest Science Program to document the effects of a wide range of initial planting densities (that is, espacements) on the growth and development of several interior conifers. A total of 21 standardized installations are distributed among nine Forest Districts and four biogeoclimatic zones (ESSF, ICH, MS, SBS). Five species (Pl, Sx, Fd, Lw, Py) and species combinations (Pl/Sx) are being tested. Descriptions of the 21 study sites are shown in Table 1. 

Objectives

To determine the effects of espacement (planting density) on the growth, development and yield of interior conifers.

Treatments

For all single-species trials, three replications of each of five levels of initial planting density (500, 1000, 1500, 2000, 2500 trees per hectare) are being tested. Treatment plots vary in size depending on espacement. At most study sites, treatment plots contain 144 trees (12 rows of 12 trees); plots contain 100 trees (10 rows of 10 trees) at two sites. 

The Pl/Sx mixed-species trial is a factorial experiment that combines three levels of planting density (1000, 1500, 2000 trees per hectare) with five levels of species' composition (proportions of 0, 25, 50, 75, and 100% of each species). The 15 combinations are replicated twice. All single-species plots contain 144 trees (12 rows of 12 trees), and all mixed-species plots contain 225 trees (15 rows of 15 trees).

All of the installations are re-measured at 5-year intervals. 

Publications

• de Montigny, L., S. Ahmed, and V. LeMay. 2016. The effects of planting density on the growth and yield of lodgepole pine, interior spruce, interior Douglas-fir, and western larch: 16- to 26-year results from EP964. Prov. B.C., Victoria, B.C. Tech. Rep. 098.
• Carsky, G. 2016. Productivity of mixed-species vs. single-species forest stands: an analysis of a mixed lodgepole pine-interior hybrid spruce spacing trial in interior British Columbia. BScF thesis. Univ. British Columbia, Vancouver, B.C.
• Johnstone, W.D. and F.J. van Thienen. 2011. The effects of plantation density on the growth and yield of lodgpole pine: 20-year results. B.C. Min. For. Range, Victoria, B.C. Exten. Note 102.