Overview

• TIPSY retrieves and interpolates yield tables from its database, customizes the information and displays summaries and graphics for a specific site, species and management regime. You can also customize the output tables by selecting the order and the variables to be displayed. Information can be entered and displayed in either metric or imperial units.

• TIPSY offers a wide range of potential input values. Clients are encouraged to rely on the guidelines and default settings provided unless local data are available. Guidelines and default values are derived from the best information available for the most common applications. This is true, however, only for those species which are actually in TIPSY's database. Some species use a substitute database, and also 'borrow' defaults. You'll see this substitution displayed in the Stand Description, which details most inputs and appears at the top of each output table. Extensive on-line documentation will help users prepare customized input data.

• The primary management variables are: initial density, fertilization, genetic gain, and pre- and commercial thinning.

• It uses optional Operational Adjustment Factors (OAFs) to mimic operational conditions. OAF 1 accounts for the reduction of physical growing space due to holes created by rock outcrops, swamps and non-commercial tree cover. OAF 2 has been used to account for decay, waste, and breakage, and some pest damage that increases towards maturity. A detailed description of OAFs was prepared by Albert Nussbaum (1998). Field procedures to estimate OAF 1 are described in:
  • OAF 1 Project Report #1 - An Overview of Stocking Gaps and OAF 1 Estimates for TIPSY
  • OAF 1 Project Report #2 - Ground-based survey method
  We have recently added the impact of Armillaria to address mortality and growth losses observed in stands of interior Douglas-fir in the ICH BEC zone. Reduction for DWB is now a separate option. It replicates inventory procedures. Reliance on generalized OAFs will continue to decline as we model more agents.

• Also, you can now create custom OAFs.

• The variable retention harvesting option reduces the amount of area available for regeneration. TIPSY accommodates both dispersed retention and group retention.

• Immediately following variable retention harvesting, you can now estimate the effect of windthrow on regeneration.

• The Genetic Gain option predicts a percent gain in volume at a designated rotation age from plantations managed under the same conditions and environment as the test sites. TIPSY uses the genetic worth of a seedlot and other information (e.g. site quality, establishment density, selection age) to forecast the yield of the improved stand at potential harvest ages. The seedlot genetic worth information can be found at the Seed Planning And Registry System (SPAR) database.

• The Existing Stand option allows you to estimate how many trees were planted based on the development of the stands in the TIPSY database. That is, you enter the top height and the total number of trees currently in your stand, and TIPSY estimates the number of trees at establishment. The process of moving backwards to establishment is quite intricate. As TIPSY "ungrows" the stand, it must also "undo" any responses to treatments or other factors that occurred in the past. Consequently, you must describe the regime in some detail. At present, TIPSY can address only single species stands established with 278 to 10 000 trees per hectare (natural, planted and clumped), genetic gain, PCT, and OAFs. It can't be used for stands of hemlock (coast & interior) and lodgepole pine above 10 000 trees, even though TIPSY's database has an upper limit of 250 000 trees for these species. Consequently, it does not address repressed stands of lodgepole.

• The fertilization option mimics fertilizer response by accelerating top height and thereby stand development. You must enter the expected percent volume response for a particular species, based on the default data and guidelines provided or your own knowledge. TIPSY then calculates the increase in top height needed to achieve the specified increase in volume. The height growth response in TIPSY is simply a vehicle for generating a volume response. It doesn't correspond to the height growth response observed in fertilizer trials, which is usually much lower. You can fertilize a stand more than once.

• You can commercial thin stands of coastal Douglas-fir and interior lodgepole pine only. Simply choose the commercial thinning treatment and select the height at which the stand will be thinned, then the residual density. Three heights are available for each species to bracket a reasonable range of harvest opportunities for each species in terms of merchantable volume, both removed and left standing, on all sites. Intermediate heights and ages may be available in the future.

• The economic analysis module, known as the TIPSY Economist (Stone et al., 1996) performs economic analyses on the silvicultural treatments simulated by TIPSY.

• TIPSY includes three options to explore dead tree dynamics: Mortality, Snags, and Coarse Woody Debris (CWD).
  • The Mortality Table is an interpolation of mortality tables generated from TASS (i.e., similar to how live tree yield tables are generated).
  • The Snag Table provides a stand table by dbh size classes of the number of standing dead trees expected at an age step. The expected number is derived from an interactive logistic model.
  • The Coarse Woody Debris option generates several different tables showing the amount of fallen dead trees (i.e., CWD).

• The job generation option estimates the number of person days per hectare (PD/ha) of labour required for silvicultural treatments, harvesting and manufacturing operations.

• A batch routine is incorporated in TIPSY for processing a large number of stands for timber supply analyses. Batch TIPSY is also included in the program WOODLOT for calculating even-flow harvest rates for a planning period on woodlot licenses. Most options available in interactive TIPSY are also available in Batch TIPSY, with the exception of economic analyses and jobs reports.

How TIPSY Works

Growth Relationships

The growth relationships within TIPSY are described in the TASS web site.

Database

TIPSY’s database includes 1658 managed stand yield tables generated by TASS and SYLVER for: coastal Douglas-fir, coastal western hemlock, Sitka spruce, western redcedar, interior Douglas-fir, interior western hemlock, lodgepole pine, white spruce, trembling aspen, and red alder. TIPSY generates any table within a limited range of parameters provided by the user. If an identical yield table does not exist, TIPSY will interpolate between the closest yield tables and electronically retrieve stand yield information.

Applications and Limitations

Applications

TIPSY generates managed stand yield tables, and product recovery data, economic analyses, batch processing and supporting graphics for:

• stand level crop planning;
• silvicultural treatments (e.g., espacement, fertilization, pre-commercial thinning);
• genetic gain;
• commercial thinning;
• forest level planning for long term timber supply projections of managed stands. A multiple species feature aggregates up to 5 stand types into the timber supply analysis units;
• repressed stands of lodgepole pine;
• dead trees (i.e., standing or fallen) and coarse woody debris;
• jobs statistics for silvicultural treatments, harvesting and manufacturing operations;
• investigations of tree growth and stand dynamics;
• generating Stand Density Management Diagrams (SDMD); and
• educational and teaching purposes.

Limitations

Some of the limitations of the current version of TIPSY are:

• it does not predict the yield of complex stands (i.e., mixed-species and/or uneven-aged stands);
• it must initiate stand growth projections at age 0 (i.e. year of disturbance). However, limited data from existing stands (i.e. top height, total number of trees, and some treatments) can be input to allow TIPSY to estimate the number of trees at establishment. Existing stand option can be used only for stands established with 278 to 10 000 trees/ha. It can't be used for stands of hemlock (coast & interior) and lodgepole pine above 10 000 trees, even though TIPSY's database has an upper limit of 250 000 trees for these species. Consequently, it does not address repressed stands of lodgepole pine. This option is also not available for multiple species, commercial thinning or fertilization treatments.
• it allows for only one pre-commercial thinning entry, and it occurs only when stands reach a top height of 4 metres in the interior and 6 metres in the coast.
• it has only three spatial distributions. Planted stands have a nearly uniform square spacing and naturally regenerated stands have a random or clumped (i.e. for only coastal western hemlock and lodgepole pine) distribution of seedlings covering the entire site.
• it does not simulate the growth of multiple species stands biologically. The only biological assumption is the site index conversion adjustment among species.

MoFR TIPSY Use Policy

TIPSY projects the growth of managed stands starting at age zero in support of silvicultural planning and timber supply analyses. Users should consider VDYP for even-aged, natural stands, and Prognosis^BC for ground-based inventories of multi-layered and partially cut stands of mixed species.

Reliability

Guidelines for use

If TIPSY does not offer the silvicultural treatment or level needed, please contact Mario Di Lucca. He may initiate special customized runs with TASS if the treatment is available (e.g. pruning, ingress simulations, or a particular spatial distribution involving a specified level of clumping).