Vegetation zones and rainfall for the island of hawai

Vegetation Maps, Zones and Rainfall
for the Island of Hawai‘i

Vegetation Maps

overstory/understory species, as ArcView SHP files - see description
from the State of Hawai`i's GIS Program - Natural Resource / Environmental Layers
3 levels of detail provided as separate files:
- VED - most detailed (snapshot at right)
- VEG/VER - more generalized / most generalized
only covers about half the land area of the island, but it covers most of the land that isn't pasture/agriculture or bare rock
classifies each polygon as one of 380 different vegetation types

Land Use

1:100,000 LULC (land use/land cover) files are available from the USGS
- 3 files cover the island: HAWAII COUNTY 1,2,3
- downloaded and viewed these files with Maptitude, resulting in this map:
- this data tells use where NOT to grow wild vegetation, by indicating developed (urban/agricultural) areas
- also indicates where the major lava flows are (important for this island!)
- the rangeland / forest zones roughly indicate density of vegetation
State Agricultural Land Use Maps (ALUM)
- in ArcView Shape File Format
- great data source! need to find a way to utilize it

Species Distribution

could plants present at a given location could be described as a list of species with density per m² ?
i have not yet found any data describing the range or density of any specific plants on the island
the USGS National Biological Service (NBS) and the Hawai‘i Department of Land and Natural Resources (DLNR) announced in 1995 (newsrelease/1995/7-12a) that they would start a Hawai‘i Vegetation Mapping Project, but the project died
there is an excellent study of Rare Plants of the Pohakuloa Training Area, but that is only a few species on a small part of the island
Jim Jacobi of the USGS Biological Resources Division (BRD)
- has species-specific vegetation data for about half the island, excluding extensively developed areas, that was put together during the 70s and 80s
- he merged in the Colorado folk's excellent Pohakuloa data
- the combined data is public domain and stored as ArcView Shape Files
- awaiting possibility of acquiring the data
National Park Service and GIS - Hawai‘i
- has Exotic Plants and Vegetation coverage for HVNP
- very detailed!! - see image to the right
- has "Vegetation" coverage for Kaloko-Honoköhau NHP
USGS DLG
- as of 2000, the USGS status map indicated that DLG Vegetation Overlay data may soon be available - is this now available? supposedly it is.
an amazing resource: Plants in the Hawaiian Environment
- by Priscilla Millen, University of Hawai‘i
- excellent description of vegetation zones:
Vegetation Zones of Mauna Loa at SOEST

Environmental Factors

in the absence of precise vegetation coverage information, how do we know where to grow the plants?
"The most important climatic factors governing plant distribution in Hawai‘i seem to be average annual rainfall at elevation below 1500 meters, and temperature and rainfall at higher elevations"
- therefore, we need a way to determine what the climate is at any given point on the island

Rainfall

there are maps for rainfall in Atlas of Hawai‘i, Second Edition:

the annual rainfall is a contour map, like this:	however, we need a height field, so i filled in the contours using PhotoShop such that the green value gives the rainfall in inches per year:

Vegetation zones

vegetation zones from Atlas of Hawai‘i, Second Edition:

the vegetation zone map uses cross-hatch patterns, like this:	i filled in the regions with solid colors so it can be quickly queried:	here's the legend for the filled map:
		vegetation.txt
Caption: "This map actually show potential vegetation, that is, the vegetation that one might predict could develop in an area, given the climate and the plant species currently present in that area. It does not take into account the vegetation, or lack thereof, in urban areas and does not depict modifications resulting from plantation agriculture, pasture, and similar factors."

maps like the above are primarily useful as a 'rough guide' for what to grow in wild areas
curiously, the vegetation zone map is omitted from the newer Atlas of Hawai‘i, Third Edition
99.06.30 tried converting the vegetation type bitmap to a polygonal coverage using ArcView
- ArcView easily loaded the image as a 4-bit BMP file
- there is raster-to-polygon functionality, but it requires the "Spatial Analyst extension" which i don't have
- so, i tried making my own polygonal theme, using the mouse to define polygons
- created an appropriate legend (a list of 10 ID values, for the 10 colors in the original bitmap)
- assigning ID values to each polygon is awkward, using the 'Edit Table' dialog
- results in an appropriately-colored shapefile
- to apply correct geographical coordinates (this cannot be done in the ArcView program itself):
  - created a 'world file' (extension BMPW) and re-imported the bitmap
  - then, had to re-create each polygon

LULC vs. Potential Vegetation

looked at the correlation between the LULC classifications and the Potential vegetation bitmap above. tested points every 150 meters and found the following coverage:

vegetation type	31 herbaceous rangeland	32 shrub and brush rangeland	33 mixed rangeland	42 forest	61 and 62 wetland	74 rock
1		3600	1657	34		3728
2	13	3242	3367	843		1710
3		813	423	2140	7	636
4	137	2196	1488	2079		1047
5		2082	989	3051	7	198
6		1158	746	17683	17	487
7	15	1414	491	4641		1318
8	252	7154	1270	4505		2959
9		5695	651	188		8799
10		164	11	13		2700

this tells us some useful information:
- the amounts in columns 32, 33, 42 tell us the relative prominence of each vegetation type
- column 74 isn't as useful, but tells us, very roughly, how much of each vegetation type is currently buried by lava flows
- using the classifications as density and the vegetation types for species present, each cell in the above table gives us an approximate guideline for what plants to put at that location

Environmental Factors

Rainfall

LULC vs. Potential Vegetation

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