Forest management/Description: Difference between revisions

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|Reference=Kallio et al., 2004; Arets et al., 2010; FAO, 2001; FAO, 2009; FAO, 2010;  Brown 1990; Carle and Holmgren 2008
|Status=Publishable
|Flowchart=ForestManagementModel.png
|Flowchart=ForestManagementModel.png
|AltText=Component flow chart forest management
|AltText=Component flow chart forest management
|CaptionText=Flow diagram of forest management
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|Description=Forest harvest  in IMAGE is driven by the timber demand per region. This demand is the sum of the domestic demand and the net import of timber. Trade is accounted for by either external models, such as EFI-GTM ([[Kallio et al., 2004]]). Logging in a region continues until the timber demand is met. A stepwise procedure is designed to attribute shares of the total demand to the different management systems. Part of the demand for timber is fulfilled by the harvest of wood from the conversion of forests to agriculture. Next, all full-grown wood plantations (at the end of their rotation cycle) of a region are harvested. Plantations are used first, as these have been established on purpose and significant investments have been made. When this harvested amount is not enough to supply the demand, other management systems are used. This can be either done by applying clear-cut cycles in semi-natural forests or by selective logging of heterogeneous forests. The share of each system is derived from inventories in different world region.
<h3>Rotation cycle logging</h3>
Per year, region and vegetation type is defined what fraction of the forests is logged by selective cut and what part is logged by clear cut (parameters from inventory by [[Arets et al., 2010]]). Selective cut only takes place on vegetation types with a high forest coverage (>75%). After logging only a fraction of the harvested wood is actually removed as timber for the market. What is left behind in the forest represents the losses during tree harvesting, either from unintended collateral tree damage or by removing unusable tree parts. Harvest in any forest management type can only take place when the rotation cycle of regrowth of a forest is completed (see table).
[[File:CycleLogging.png|thumb|240px|right|alt=Table describing the rotation cycles for forest management types in different forests|Table: Rotation cycles for forest management types in different forest biomes.]]
<h3>Fuel wood</h3>
Part of the energy needs of the regional population is fulfilled with wood, called fuelwood. Only part of the fuelwood is harvested by industrial forestry activities, and can be coupled to the described management systems above.  There are several informal ways to produce and collect fuelwood, next to industrial production: orchards, roadsides, forest management residues after timber removal, etc ([[FAO, 2001]]; [[FAO, 2009]]). Exact data on informal fuelwood production are missing, and therefore assumptions have been made.  In the developed regions, it is assumed that fuelwood is produced on industrial scales and therefore all fuel wood demand is added to the timber demand. In the transitional regions 50% of the fuel wood demand is coming from timber and in the developing regions 32%.
<h3>Establishing wood plantations</h3>
Wood plantations are established on purpose to provide specific wood qualities in an efficient way. The expectation is that in future, more and more wood will be produced from plantations. For this, plantation planting rate scenarios have been drawn up by FAO ([[Brown 1990]]; [[Carle and Holmgren 2008]]). In the IMAGE model wood plantations are established on abandoned agricultural land, and this process can be called reforestation. If there is not enough abandoned land, they will be established on clear-cut forest areas, where the forest coverage of the original natural vegetation type should be more than 75%.  A wood plantation is specifically planted for roundwood or for pulpwood. Once a wood plantation is established this area cannot be used for other purposes, and it cannot change back to natural vegetation until after the rotation cycle and subsequent wood removal.
<h3>Additional deforestation</h3>
A special type of forest use in IMAGE is the so-called “additional” deforestation.
With this additional deforestation extra areas of forest are converted in addition to the deforestation in IMAGE caused by agricultural expansion. This process is included as a correction factor, and is due to unmodelled conversion. Additional deforestation is not a forest management type because the wood is not used for timber but the process  is part of the forest management module. The areas are slashed and the wood is left behind in regions with higher latitudes and burned down at the lower latitudes. No recovery to natural vegetation takes place in these areas and no agricultural activities can be started. Logging for additional deforestation in a region only starts after the demand for timber is satisfied.
The additional deforestation is driven by the difference of the regional deforestation data of the ([[FAO, 2010]]) and the agricultural expansion data of the IMAGE land use model .
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