Growth Form and Ecotypes

MEGAN landcover distribution data: Growth Forms and Ecotypes

The Growth Form and Ecotype data available from this website are global 30 second (~1 km2) spatial resolution but MEGAN has been run using the higher spatial resolution landcover data in selected areas including the contiguous USA at 30 meters and selected urban areas at 0.6 m.

NOTE that these are large datasets (~1 Gbyte).

Growth forms:

The MEGAN growth form scheme includes just four categories (crops, grass/herbaceous, shrub, and tree). This provides a first order characterization of that can be well characterized using aerial imagery on global scales. The three versions available here are the GF1, GF2, and GF3b datasets.

MEGAN first generation Growth Form dataset (GF1): This dataset was generated for use with MEGANv2.1 in 2011 and is described by Guenther et al. 2012.

MEGAN second generation Growth Form dataset (GF2): This dataset was generated for use with MEGANv2.1 in 2017 and is the same as GF1 except that it has been updated for the contiguous USA as described by Yu et al. (2017) The four files (0.72 Gb each) can be downloaded here: crops, shrub, grass, total tree.

MEGAN third generation Growth Form dataset (GF3a): This dataset was generated for use with MEGANv2.1 or MEGANv3.1 in 2020 and is the same as GF2 except that it has been updated for Australia. The four files (0.72 Gb each) can be downloaded here for crops, tree, grass, shrub. Note that this file requires the use the updated version of the MEGAN FORTRAN preprocessor if you are using version GF3 or higher: MEGAN31_Prep_Code_July2020

In addition, MEGAN divides trees into broadleaf vs needleleaf and tropical vs extratropical in order to get canopy types for the canopy environment model. Global datasets with this information are available here: needleleaf tree fraction, tropical tree fraction

Ecotypes:

Growth forms are insufficient for assigning BVOC emission types since, for example, different tree species can have very different BVOC emission rates. MEGAN defines ecotypes that are composed of a specified mix of emission vegetation types that are associated with specific emission capacities. Ecotype distributions are typically based on satellite imagery and ground surveys to characterize the vegetation types. The two versions available here are the EVT1, EVT2, and EVT3 datasets.

MEGAN first generation Ecotype dataset (EVT1): This dataset was generated for use with MEGANv2.1 in 2011 and is described by Guenther et al. 2012.

MEGAN second generation Ecotype dataset (EVT2): This dataset was generated for use with MEGANv2.1 in 2017 and is the same as EVT1 except that it has been updated for the contiguous USA based on LANDFIRE data. This large (1.42 Gb) file is available here .

MEGAN third generation Ecotype dataset version b (EVT3b): This dataset was generated for use with MEGANv2.1 or MEGANv3.1 in 2020 and is the same as EVT2 except that it has been updated for Australia and Southern California. This large (1.42 Gb) file is available here: EVT3b. Note that this file requires the use the updated version of the MEGAN FORTRAN preprocessor: MEGAN31_Prep_Code_July2020