Vegetation mapping and classification project: Redwood National and State Parks, California

Stumpf, Kenneth; Cogan Technology; Kier Associates

A vegetation classification and map of Redwood National and State Parks (RNSP) was created from remotely sensed and ground-verified data as a part of the National Park Service Vegetation Mapping Inventory (NVMI) Program. The project was undertaken to provide baseline vegetation data and information for NPS resource management and the general public. Products of this project include a digital vegetation map fomratted for ArcGIS, a taxonomic classification and key, quantitative floristic vegetation plot data, and this report, which describes of methods and findings. Floristic, physiognomic, and environmental data were collected from three hundred fifty-five (355) vegetation relevés, in order to classify and describe vegetation. Fifty-one (51) vegetation types at the approximate level of generalized alliance, and usually at the level of association were described. The map employed the U.S. National Vegetation Classification (USNVC) to map 142,062 acres (57,491 hectares) of RNSP. Forty-five (45) vegetated map classes at the level of USNVC alliance and four non-vegetated land cover classes were mapped. Eighty-nine (89)% (126,796 acres) of RNSP mapped as forest or woodland, 0.9% (1,322 acres) was mapped as shrubland, 3.7% (5,294 acres) was mapped as herbaceous vegetation, 1.4% (2,053 acres) was mapped as barren, 4.2% (6,035 acres) was mapped as water, and 0.4% (562 acres) was not classified and was mapped as unknown land cover. Old-growth coastal redwood forest characterized by coast redwood (Sequoia sempervirens) and Douglas-fir (Pseudotsuga menziesii) grows on approximately 30% of the parks, the majority of which occurs within the three state parks. Second-growth stands of forests are characterized by Douglas-fir which becomes re-established following fire or logging more quickly than do coast redwoods. Dry forest communities have become established in the Redwood Creek basin along the ridges from Slide Creek to Coyote Creek. Little Bald Hills include an area of about 1,500 acres (607 hectares) of serpentinite soils in the northeastern portion of the parks. Dry ridgetops support scattered Jeffrey pine (Pinus jeffreyi) with an herbaceous understory of Idaho fescue (Festuca idahoensis) in the Little Bald Hills area. A complex mosaic of plant communities including coniferous forest, Oregon white oak (Quercus garryana) woodland, and grassland types occur in the Bald Hills. Coastal scrub, coastal grasslands, and Sitka spruce and red alder forests occur in a narrow band along the coastal bluffs, while coastal dunes and beaches support communities adapted to their harsh and changing conditions. A thematic accuracy assessment was conducted on the 30 most abundant vegetation classes, employing 512 observations throughout RNSP. The overall accuracy at the alliance level vegetation classes was found to be 65.5%. When the classes are aggregated to thematically coarser levels, the accuracy is 86.2% at the USNVC group level and 95.4% at the level of USNVC macrogroup. The true areas of each class, adjusted for mapping error, were estimated for 35 map classes. This information is informative for management, since it enables more representative estimates of the true areas of vegetation classes, accounting for tendencies to over-map or under-map individual types.

Vegetation mapping and classification project: Redwood National and State Parks, California

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