Version 2.11

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2018-05-17

Summary

  • Version 2.11 have changes that will affect the results. Using the same settings as in an earlier version may give slightly different thinnings results, at least if there are many small trees.
  • Functionality for understorey cleaning in thinnings has been added.
  • Biofuel thinning can be triggered automatically if there are many understorey trees.
  • Mean volume of harvesteed stems does not include small trees anymore
  • No specific pricelist is required for biofuel thinnings, the biofuel price in the ordinary price list is used.

Updates for version 2.11

Version 2.11.1

(2018-05-18) The bugfix described below ("Time period for young stand thinning...") was unfortunately not included in yesterday's release of version 2.11.0. An update will be published today. See also table with changes below.

Important bugfix: Time period for young stand thinning was often delayed one period

A bug in the treatment program generator often prevented young stand thinnings to be applied in the first harvest period: For example, if thinning was applicable in period 1, then it was postponed to period 2. The problem occurred for stands that were classified as young and yet unthinned stands by Heureka at the start of the planning horizon, or for generations simulated after final felling. See bug 211

New feature: Understorey cleaning in thinnings (sw: underväxtröjning vid gallring)

Understorey cleaning means that small trees are removed before thinning. Typically these trees have dbh < 8 cm and have no commercial value, but constitute a hindrance to the harvester machine. Rules for understorey cleaning is determined by a set of new parameters in the TreatmentModel control table, for example a diameter limit for classification of understorey trees, and a stem density threshold that will trigger such a cleaning. The cost for understorey cleaning is entered in the Cost and Revenue control table as a per-ha fixed cost. There is also an alternative cost for NOT doing an understorey cleaning when there are many understorey trees (parameter "Harvester Time Increase from Understorey Trees"). By default, the time increases by 0.4 cmin/tree for every 1000 understorey trees that remain when doing a thinning. You can read more about understorey cleaning in this new help chapter.

New feature: Biofuel thinning can be triggered automatically if there are many understorey trees

You can tell the program to trigger a biofuel thinning if the number of understorey trees exceeds a certain limit (parameter "Understorey Density Trigger Biofuel Thinning" in the TreatmentModel control table). The feature is deactivated by default. Read more here: Help doc.

Modification: Mean volume of harvested stems does not include small trees anymore

The built-in harvester cost functions use mean commercial volume (m3fub) of harvested trees as an important explanatory variable. Since Heureka can harvest smaller trees, the volume of these has been included in this variable too, and small trees with zero commercial volume, that are not extracted but left on the ground, has been added anyway, assuming a volume of 0.8 x the tree volume. However, it has become clear that this approach may lead to an overstimatation of harvest cost if there are many small trees. Therefore, since we know have the possibility to handles understorey trees, only trees with a commercial volume are included in the harvester cost. The forwarding cost has been handled as expected, and only included the forwarded trees.

A new result variable has been added related to this, see Mean Tree Volume Harvested in table below.

Changed control table parameters: "Min Diameter Thinning" changed to 8 cm and "Min Diameter Selection Felling" added

In the Treatment Model control table, there is a parameter called Min Diameter Thinning, which as default has been set to 4 cm. This parameter is a size limit for which trees should be eligible for thinning. This has been changed to 8 cm to harmonize with the new understorey cleaning functionality. This parameter has been common to Thinning and Selection Felling, but now a specific parameter hsa been added for Selection Felling.

Changed control table parameters: "Thinning Period Delay Max Generation 2" added

In the Treatment Program Generator control table (PlanWise and StandWise), there is a new parameter called "Thinning Period Delay Max Generation 2". This has the same type of funtionality as Thinning Period Delay Max, but is applied to generation 2 and later if you have not assigned a specific control category for generation 2. Setting this parameter to a small value (as is default) means that the number of possible thinning schedules decreases after final felling of the current stand. The purpose is to decrease computation times. The rationale for narrowing down the thinning range in later generations is that future activities should be less important to spend exhaustive computation time on than activities in a nearby future.

Simplification: No additional pricelist required for biofuel thinning

Biofuel thinning is a special type of thinning that can be applied in young stands, and can also be triggered automatically from this version of the program (see above). Biofuel thinning has its own cost functions, since the machinary is different from a single-tree thinning harvester. In bio fuel thinning it is assumed that all cut trees are sold as biofuel. To handle this in Heureka, until now you had to do a workaround by entering a specific price list with a large top diameter limit for timber and pulpwood. As a result, only bio fuel was obtained from the trees. This was an unnecessary complicated solution! Instead, all cutt trees in biofuel thinnings are now considered bio fuel, and the price is retrieved from the same pricelist used for thinnings.
You can read more about this in the help documentation

New result variables: Mean Tree Volume m3fub and more

The following result variables have been added

Name Result Group Unit Description
Mean Tree Volume Harvested
Financial Value m3fub/tree Not to be confused with the old variable "Avg Volume per Felled Tree" in result group Treatment which is given in unit m3sk/tree. Mean Tree Volume Harvested is a result from bucking (aptering), while "Avg Volume per Felled Tree" is a result from ordinary tree volume calculations and includes all felled trees, which is why they are located in different result groups.
Understorey Cleaning Cost Financial Value cost per ha Cost per ha for understorey cleaning (underväxtröjning)
Understorey Stems Forest Data tree/ha Number of trees in established stands with dbh < MadDiameterUnderstorey (in TreatmentModel control table).
Understorey Cleaned Treatment trees/ha Number of understorey trees removed before a thinning.

New page for benchmarking released program versions

When releasing a new version, we run a test problem and summarize some key figures. See page Version benchmarking

Bug fixes and other changes

Id Category Severity Summary Fixed_in_version Resolution Comment
0000211 TPG major Youngs stands not thinned in first harvest period even if thinning criteria met 2.11.1 fixed
(PlanWise) A bug in the treatment program generator prevented young stand thinnings to be applied in the first harvest period (period 1 when period midpoints are used).
0000212 TPG minor Thinning Period Delay Generation 2 only applied from generation 3 onward 2.11.1 fixed Thinning Period Delay Max Generation 2 is now also applied to generation 2 as expected
0000213 TPG tweak Treatment program generator tests alternatives with invalid thinning periods 2.11.1 fixed The TPG algorithm evaluated management schedules that could be dismissed earlier in the algorithm. This lead to unnecessary computations.
0000214 TPG minor Enforced thinning sometimes applied even if a valid thinning period is found 2.11.1 fixed
0000192 Visualisation StandWise minor Adding a DEM (Digitial Elevation Model) in StandWise results in an index error. 2.11.0 fixed
0000198 TPG minor Initial bare land is not regenerated when rerunning a simulation when using NFI-data plots as input data 2.11.0 fixed The function for rerunning an optimization result in PlanWise (introduced as beta in version 2.6) or simulation result in RegWise, did not handle regeneration of initial bare land as it should when using NFI-data plots as input data.
0000205 TPG major Initial state mean age for young plantation set to 0 after TPG 2.11.0 fixed If you have clicked the "Update"-button in the Initial State window after running a simulation, the mean age of young plantations have been reset to 0, even if they were for example 2 years old. This has been a bug since version 2.8.0 (September 2017). The error have not affected simulations and results, only the tables and graphs in the Initial State window, and only for young plantations. Results reports in PlanWise and RegWise have not been affected.
0000206 TPG minor Rerun of simulations for unmanaged stands ignored period midth 2.11.0 fixed
0000207 TPG minor Print tree list during rerun of simulation crashes the program for large simulations 2.11.0 fixed
0000208 TPG feature Add a button that allows the user to select species of trees to print to log 2.11.0 fixed
0000201 Other minor Error when saving and loading default result variables in result variable selection dialog 2.11.0 fixed
0000210 Other minor StandWise hangs when selecting properties 2.11.0 fixed Occurs when no habitat models are present in Common-directory, and the HabitatModels.zip is missing. Attempt at unzipping a non-existent file crashes StandWise. The problem did not occur if PlanWis or RegWise had been run, since the habitat models are included and extracted in those applications.
0000199 Optimization feature Spara del av optimeringsmodell 2.11.0 fixed
0000191 Map minor Error "Invald column name..." when saving shapefile 2.11.0 fixed This bug first occurs in version 2.10, and was caused by an incorrect column name IsNcUnitSetAsideDuringImport leading to an SQL exception when trying to save a shape file from the "Initial State" map window.
0000209 Installation major Exception in StandWise if neither PlanWise or RegWise has been run due to missing habitat model files. 2.11.0 duplicate
0000195 Growth / producton major Inconsistent growth in StandWise 2.11.0 fixed Stems residual was not reset when backing a PredictionUnit, causing the value to remain for subsequent programs after resetting
0000197 Growth / producton feature Skip pricelist for biofuel thinning and assume all felled trees are bio fuel 2.11.0 fixed See help doc on setting biofuel price
0000189 General minor Price trend handler may start unnecessary recalculation 2.11.0 fixed Unnecessary recalculation removed.
0000204 Data import minor User should be notified when column names are wrong in tree list import files 2.11.0 fixed When importing tree-level data, miss-spelled column names would be ignored resulting in data not being imported as expected. The user is now notified if column names are wrong or mandatory columns are missing.
0000202 Control categories minor No pricelists selected after adding cost control table from file 2.11.0 fixed
0000203 Control categories minor Control table file name should be added so user can separate different versions 2.11.0 fixed