Permanent Sample Plot

Overview of Program

The B.C. government began installing permanent growth and yield (GY) plots in the 1920s. Increasing interest in GY data led to the creation of a joint government-industry advisory council. In 1986, this became the Forest Productivity Council of BC (FPC). Under FPC guidance, many permanent sample plot (PSP) programs merged to form the current Provincial PSP Program. Before FPC disbanded in 2002, it established standard PSP protocols and program management tools that are still in use today. The FPC “matrix” arrays the even-aged PSPs by:

  • Biogeoclimatic Ecosystem Classification (BEC)
  • Species
  • Age
  • Density
  • Site index

Modified versions of this matrix are still in use. They help determine new installations, re-measurements and plot protection status.

The primary purpose of PSPs has always been to develop GY models. GY models provide future forest predictions essential to many business applications. Long-term PSP data are also used to:

  • Calculate stand dynamics, regeneration and mortality data
  • Calibrate carbon/climate models
  • Model old-growth health and dynamics
  • Provide empirical evidence of recovery after catastrophic forest health epidemics
  • Supply many other research and development (R&D) applications

The corporate value of the PSP legacy thus links to the corporate value placed on GY models.

PSP plots are deliberately located to sample a wide range of stand conditions and growth trajectories. This includes conditions that are essential for broadening the predictive scope of GY models to address future stand conditions.

PSPs in natural stands provide the biological baseline within both unmanaged and managed  stand models. Managed stand models then build on this baseline with more intensive research data.

The priorities for the PSP program are:

  • Loading backlog PSP data
  • Re-ranking the PSPs by status, condition and mensurational information
  • Protecting plots by map notation
  • Ensuring effective database management

Government has the responsibility for maintaining the province’s PSPs and associated database. There are approximately 9,000 PSPs provincewide; the ministry owns or manages close to 5,000.

PSPs provide valuable information for:

  • Climate change analysis
  • Forest and range resource measurement
  • Non-forest resource measurement, such as biomass and carbon
  • Sustainable forest management applications, such as modelling forest health and dynamics
  • Sustainability policies and practices development
  • Habitat management and biodiversity
  • Post mountain pine beetle recovery dynamics

PSPs are not officially protected from harvesting, but about 2,300 do have a “Map Notation” designation. Most, with the exception of about 230, are easily locatable through the Land and Resource Data Warehouse or web.

PSPs matter because they are the province’s only natural stand data set that has been re-measured over time. The PSP database is a valuable resource, having an estimated replacement value of $80 million.

Unfortunately, field surveys show that some PSPs have been harvested in recent years without any prior consultation. This resulted in the loss of valuable data forever.

Harvesting plans should always consider whether a ministry-managed PSP is in a conflict situation. If so, the Forest Inventory office will review the PSP and work with the interested party to determine if

  1. Final re-measurement is recommended
  2. Protection is required
  3. Release is granted

Below you can read a letter from the chief forester on the protection of PSPs. You can also read a set of instructions on how to locate PSPs on the Land and Resource Data Warehouse.

PSP information has been compiled and put into a CSV format file. The accompanying data dictionary can also be downloaded below.

PSP information can also be found on the Land and Resource Data Warehouse.

Download the complete RISC Growth and Yield, Permanent Sample Plots document (PDF, 2.3 MB) (version 2, November 2007). Otherwise, download separate chapters below (not available on the RISC site).