Is there long historical data (at least a few centuries back), at the world level, of forest area? I've only found data by the FAO starting in 1990 (see here). There is some older evidence for a few regions and countries but no aggregate measure (for instance, see here). Any help is appreciated.
$\begingroup$ It is highly improbable that the data you are looking for exists. When I was roaming Borneo in the 1960s, there were substantial areas of the map left blank because they hadn't been mapped. We had to substitute aerial photographs. My information is that the same situation existed and to a lesser extent still exists in other rainforests. There is no possibility of accurate maps or measurements a few centuries back. $\endgroup$– Michael WalsbyMar 2, 2020 at 19:43
$\begingroup$ @MichaelWalsby There is some hope — with considerable difficulty it may be possible to estimate historical forest cover. See earthscience.stackexchange.com/q/5262/6. However, it would be a huge effort to establish such a record on a global basis, so I agree that such a dataset probably doesn't exist with any level of accuracy and precision. $\endgroup$– gerrit ♦Mar 3, 2020 at 9:15
1$\begingroup$ @MichaelWalsby Economists have (with a debatable degree of accuracy, for sure), computed GDP for the world since 1AD. That's a way more difficult task imo. You mention Borneo. Well, based on some recent information, surely something can be deduced. I mean, if there is a rainforest now, there must have been 100 years ago, and perhaps 500 years ago. We are not talking about exact metrics here. Even a rough estimate would be useful. $\endgroup$– luchonachoMar 3, 2020 at 12:47
2$\begingroup$ @luchonacho It would be useful if you added the spatial resolution that you're interested in, e.g., country level, 1 degree, 100 metres. As the other comments mention, some things will be more feasible than others. $\endgroup$– DeditosMar 3, 2020 at 13:04
$\begingroup$ A lot of British forest, mainly oak, was cut down to build England's famous 'wooden walls', but I doubt that there are any accurate records of the clearance.. $\endgroup$– Michael WalsbyMar 4, 2020 at 11:45
When I need data about past and future projected land use change, I usually refer to the global dataset that was developed for the global climate simulations CMIP6. The dataset is the Land Use Harmonization V.2 LUHv2 and it was developed by researchers at the University of Maryland.
Reading the supporting document of the dataset, among others, the following characteristics are reported:
- global domain;
- 850‐2100 annual land-use states, transitions, and gridded mgt layers;
- 0.25 x 0.25 degree spatial resolution;
- 12 possible land-use states including separation of Primary and Secondary natural vegetation into Forest and Non‐forest sub-types, Pasture into Managed Pasture and Rangeland, and Cropland into multiple crop functional types
The dataset is composed of a set of simulations using different land surface models:
These datasets are being developed as a contribution of the Land-Use Model Intercomparison Project (LUMIP) to the Forcing Group for CMIP6
Data can be downloaded from this page.
Of course, the layers you find here are "just" models' results, but as much as past observations made a good calibration possible, the variations reported are likely be the most accurate information about the evolution of the world forested areas currently available.
$\begingroup$ Thanks. Looks promising. It has a file from 815 AD to 2015 indicating whether area is forest or not. Looks like the building block to compute what I want. Not sure what format data comes in though. $\endgroup$ Mar 3, 2020 at 15:45
$\begingroup$ @luchonacho The files are in netCDF (
*.ncfiles). It is quite stright-forward to work with them in a Linux environment (similar under MacOS). Might be a bit difficult under Windows. There are Python and R netCDF4 packages available. The basic netCDF library offers the binary
ncdumpto print out the header of netCDF files (
ncdump -h FILENAME). Quick plotting of netCDF content: ncview or Panoply. $\endgroup$ Mar 3, 2020 at 20:14
$\begingroup$ @luchonacho, in addition to what Danel righly pointed out, you can also convert netCDF files in raster files using Arcmap (desktop.arcgis.com/en/arcmap/10.3/manage-data/netcdf/…). I'm sure also QGIS would have similar functionalities. $\endgroup$– NemesiMar 4, 2020 at 11:07