Version 1.5

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[[::Version 1.5|English]]

2011-09-01

Summary

Version 1.5 contains fixes of bugs that lead to too few thinnings. New features include possibility to add user-defined result variables for occurence of large trees of selected species.

New features

• Abundance of large trees are important for biodiversity. You can now define your own result variables for volume or number of large trees, and select species and diameter criteria for these variables. Read more here. Note! Not to be confused with user-defined input variables when importing stand data!
• (PlanWise and StandWise) The thinning criteria for the first thinning has been relaxed, so that it is sufficient that the basal area is ≥ 90 % of that dictated by the thinning guide to consider a thinning (instead of 100 %). This is more in accordance with how the thinning guide should be interpreted in practice (as a basal area interval, not only a midpoint value). This should lead to more thinning alternatives.
• When making a prognosis for a period length less than 5 years, interpolation is applied to each tree object. In previous verioins, linear intepolation was used for tree diameter, stem number and height. In an ongoing validation project, it was discovered that the interpolation per se causes deviations of up to 2 % on stand volume after 20 years, if starting with an interpolation to 2.5 years (to use period midpoints). A new non-linear interpolation algorithm was therefore implemented that minimizes the interpolation error to neglectable values. The algorithm uses growth, change of stems, etc. for two growth period ahead to estimate the rate of change (i.e. second derivative) for each tree attribute. This information is then used to compute interpolated values.
• PlanEval now supports participatory planning, so that several stakeholders can "vote". Only preliminary version though.
• In PlanWise, a new fertilization policy is available that allows fertilization every ten years before final felling, starting from established forest stands (i.e. not in young stands).
• When importing stand register data, there are a number of data columns open for you to enter any additional data (called UsedDefinedVariable1 - UserDefinedVariable10). You can now rename the headings of these columns, and these names will be available in table views etc (currently, they are only visible in StandWise).

Bug fixes

• In March 2011 an error was unfortunately introduced that prevented second and later thinnings to take place. Hence, the problem should exist in version 1.3 and 1.4, but not in versions before that. This has been fixed.
• In existing stands (not in stands where regeneration is simulated) with major species other than Scots pine or spruce, for example contorta or oak, the dominant height for the site index species has been used as input to the thinning guide insted of dominant height for the dominant species. For example, in contorta stands, the dominant height for Scots pine has been used instead of dominant height for contorta. Note that the system only handles site index for pine and spruce (site index for birch can be imported but is then converted). This may have lead to that some thinnings in contorta stands have not been simulated, or that the timing of thinnings has been faulty.
• En error that lead to overestimation of tree height has been fixed (for tree height development option "ElfvingEriksson". You can expect 1-5 % lower growth rates than in previous versions.
• Prediction of mortality and damages in young stands has been modified to be better adapted to tree group list (where a tree object may represent several trees). Also, some bugs have been fixed. Mortality rates are often slightly higher in version 1.5, and amount of non-lethal damages that cause height growth reductions are slightly lower. The effect on total production is probably less than 1 %.

Details

More details can be found here: Release Notes 1.5 (Click "Cancel" if a login-screen is displayed.)

Known issues

• The evaluation of forest domains when running Tactical Treatment Program Generator is time consuming. A patch solving this problem will be released 2011-09-08.

Ongoing activities

The growth-and-yield part of the system is currently being validated against 370 long-term growth experiments (30-50 year series, "gallrings- och gödslingsförsöken"). Preliminary results indicate that Heureka performs pretty good, possibly with some overstimation of growth rates after thinning from above. It is noteworthy that other systems has not undergone this extensive testing.

Next release

Probably in October 2011. Planned activities:

• Add user-defined thinning guides.
• Add handling of initial dead wood when using stand register data as initial data.
• Some other things!