Forests & Plantations

Forest land is an area of major interest, and an important factor in the evaluation of energy, agricultural, and climate change policies. The tension among agricultural, forest, and "other" lands is central to the FeliX model and has been discussed here.

Model results and FAO data on total forest area. At bottom, the expansion of managed forests and plantations (by 2 orders of magnitude) is shown in lime green. The demarcated regions around the  Total Forest  and  Managed Forest  results indicate the consequences of high and low population scenarios.

Model results and FAO data on total forest area. At bottom, the expansion of managed forests and plantations (by 2 orders of magnitude) is shown in lime green. The demarcated regions around the Total Forest and Managed Forest results indicate the consequences of high and low population scenarios.

Shown above, total forest land is predicted to remain relatively stable at around 4 billion hectares through 2100. FAOSTAT historical data for the period [1990-2012] is also plotted. However, this general prediction belies several real threats to forest ecosystems and the valuable habitats they represent.

First, expansion of managed forests or plantations into formerly pristine areas replaces complex ecosystems with monocultures, with several important consequences: 

  1. Increased susceptibility to disease, climate change, drought, and invasive species
  2. Habitat destruction and biodiversity loss
  3. Potential soil degradation and carbon stock reduction

Secondly, through the current century, expansion of agricultural land is predicted to result in the destruction of nearly 700 million hectares of "other" natural habitats such as grasslands (discussed here). Though the model does not assign this burden to forests, they are vulnerable to being cleared for profit or even in the pursuit of food security. To wit, the high population scenario does predict both 10% deforestation and heightened demand for plantations by 2100.

Thirdly (and relatedly), forest area predictions are heavily dependent on agricultural yields. If yields fail to keep up with population growth, rising food demand (especially animal products) will make cleared land (i.e. pasture) more valuable even than heavily-managed forests. 

Deforestation rates are used in the calculation of land use change emissions

 

Land Use I

Land in the FeliX model is distributed among four mutually exclusive and collectively exhaustive categories: agricultural, forest, urban/industrial, and "other".

Agricultural, forest, and other land for the period 1950-2100 shown with historical data available from the FAO. Annotations note the extent of each type of land in 2010 and 2100.  Urban/industrial land represents an additional (static) 40 Mha.

Agricultural, forest, and other land for the period 1950-2100 shown with historical data available from the FAO. Annotations note the extent of each type of land in 2010 and 2100. Urban/industrial land represents an additional (static) 40 Mha.

Each category is calibrated to FAOSTAT data on a global level (available for 1961-2010 for agricultural and 1990-2012 for forest and other land). Though not on a geographically explicit basis, land can be repurposed--most notably, due to changes in demand for agricultural land.

Between 2010 and 2100, growth in global population and per capita GDP leads to a 17% expansion in agricultural land (a collective label for arable land, permanent crops, and permanent meadows & pastures). This expansion is driven by both supply- and demand-side factors. 

Schematic diagram of land use in the model.                   (Click to enlarge)

Because land is a finite resource, transitions are zero-sum (modulo discrepancies due to rounding above). In the BAU scenario, agricultural land expands at the cost of natural habitats included in forests and "other" land (i.e. grassland). Though this burden appears to fall entirely on the latter category, the general category of "forest" includes in this case both natural and managed plots, masking a significant threat of deforestation or degradation (a trend which will discussed in another entry).