Title
Mapping Old Growth Douglas Fir, Redwood and White Fir in Six Rivers National Forest

Author

Jasmyn Bragg
American River College, Geography 360: Data Acquisition in GIS; Fall 2016
Contact Information (w1135188@apps.losrios.edu)

Abstract

Old Growth Forest is an important factor in the overall biodiversity of the national forest. The purpose of this project is estimate how much Old Growth exist in Six River National Forest.

Introduction

Of the all National Forests in the Pacific Southwest, Six Rivers National Forest is the youngest. It was established on June 3, 1947 by President Truman. It is named for the six major rivers that run within in it: Eel, Klamath, Mad, Smith, Trinity and Van Duzen. The newly established forest initially encompassed 900,000 acres; having formed from portions of the already established Klamath, Trinity and Siskiyou National Forests. It must be noted that this area that would become part of Six Rivers NF was once the homeland for many of the Native American groups such as the Hupa, Yurok, Tolowa and Karuk. To this day, many of these communities continue to maintain ties and connections to these lands. This in turn has led to tension with the U.S. Forest Service.

(http://www.foresthistory.org/ASPNET/Publications/region/5/six_rivers/sec4.htm).

Today Six Rivers NF has 957,590 acres of National Forest and 133,410 additional acres not under federal ownership (http://www.fs.usda.gov/main/srnf/about-forest). The Six Rivers NF is a narrow strip of land that extends 140 miles from the Oregon border to Mendocino County down south. Approximately 43% of Six Rivers NF is in Del Norte County. With 35% in Humboldt county, 21% in Trinity County and lastly 1% in Siskiyou County. (http://www.fs.usda.gov/main/srnf/about-forest). For the purposes of this project, focus will be on forest that is solely within Humboldt County.

Old Growth forests make up approximately 137,000 acres of the 957,590 acres of Six Rivers NF and the 133,410 acres under federal ownership. These forests include tree types such as Douglas Fir, Pacific Madrone, Redwood, Tanoak, Red fir, Jeffrey pine, mixed conifer and White Fir. A large percentage of old growth forest that exists in Six Rivers NF are Douglas Fir or a Douglas Fir mix. A smaller majority are White fir, Red fir, Jeffrey pine, and mixed conifer. It should be noted that there are multiple definitions of old growth.

In California, there are approximately 2,525,066 acres of old growth (Bolsinger 1993). That is in comparison to the 9.5 million acres surveyed in California from 1933-1945. It is unknown how many acres existed before the 1900s. The causes of such drastic change include timber harvesting, road building, wild fires, disease and residential development. (Bolsinger 1993). Most of the forest today have vegetation spanning several different ages and species. Some of which has been replanted. Old Growth forest are important because they contribute to the overall biodiversity of the forest and are a crucial habitat to many wildlife species that live within and depend upon it. They also store large amounts of carbon aids in the slowing of global warming (Bolsinger 1993). The purpose of this project is to map old growth forest that exist in the Humboldt County Portion of Six Rivers NF. Special attention will be paid only to Old Growth Redwood, Douglas Fir and White Fir trees.

Background

The first systematic inventory of national forests in the Pacific Southwest was in the 1930s. This was largely influence by the McSweeney-McNary Forest Research Act passed in 1928. The act established periodic surveys of the national forests (Bolsinger 1993). These early surveys were completed using maps. In the 1970s, aerial imagery was used in addition to maps. By 1989 satellite imagery and ortho photographs were being utilized (Area of). In 2010 the Conservation Biology Institute release datasets displaying old and young growth Forests in the Pacific Northwest. Their dataset used a type of unsupervised classification and Landsat 7 Enhanced Thematic Mapper Plus imagery. As well as Digital Ortho Quad images and field investigations.

The U.S. Forest Service releases vegetation mapping every few years. The most current vegetation classification and mapping was completed by the U.S. Forest Service in May 2014. The Northwest Forest Plan is another great source of information. It is an interagency regional monitoring program between the U.S. Forest Service, National Park Service and Bureau of Land Management in the Northwest portion of the U.S. In 2005 they published Late Successional and old growth forest data and reports for Oregon, Washington and California. They continue to put out new data.

Methods

I downloaded GIS data from the Humboldt County Website. Data such as county boundaries, cities, roads and trails. GIS Data from Humboldt County Website are in NAD 27. I researched and acquired vegetation, transportation, timber suitability and national forest data for California from the U.S. Forest Service. Vegetation classification data is split for the state of California to reduce the size of the data set. I choose Zone 1, North Coast Mid because it encompassed Six Rivers NF and Humboldt County. Data downloaded from the U.S. Forest Service was in NAD 83. I used the Humboldt County boundary to clip the transportation data from the U.S. Forest Service. In the National Forest data, I isolated the Six Rivers National Forest boundary through a definition query. I then exported that data to form a new feature class. That Feature class representing the forest boundary was then used to clip the vegetation classification feature. Using the attribute table of the newly clip vegetation layer, I selected the desired tree types. I choose only to display the Redwood, Douglas Fir and White Fir tree types. I displayed the field attribute that listed the tree types using different colors to differentiate between the three. Using those selected tree types, I summarized the field and added the table to map. I then downloaded Late-Successional/ Old Growth data from the Northwest Forest Plan Site and added that to the ArcMap. That data would be used to determine which of the three tree types displayed, were old growth. I had to query out any null values from the Late-Successional / Old Growth Data. I then spatial joined the Late-Successional/Old Growth with my vegetation layer. Some data was lost through that spatial join. I then symbolized the layer by Tree type. I ran a summary on the tree types as well as the shape area. The resulting table was added to the table of contents.

Figure 1 . Results Table

Results

Of the three tree types, most of the old growth vegetation was Douglas Fir. There was a lesser amount of old growth white fir. Lastly a small amount of old growth redwood trees by the Oregon border. I summarized the area of all three tree types and found that there were almost 37,000 acres of old growth Douglas Fir, Redwood and White Fir forest in Six Rivers NF.

Figures and Maps

Figure 2. Cal Fire Forest Range and Assessment Data. Queried by Tree type.

Figure 3. North West Forest Plan- Late Successional/Old Growth Data with in Humboldt County

Figure 4. Spatial Join of Late Successional/Old Growth and tree type vegetation.

Analysis

I initially had difficulties with the projection of the shape files. Most if not all of the Humboldt County data is in NAD 27. U.S. Forest Service Data is in NAD 83. A warning did pop up in ArcMap but did not hinder the features being displayed together. I also struggled with acquiring relevant data. A significant portion of my time was spent researching and combing through the metadata. Even the late successional/ old growth data that I acquired through the North West Forest Plan took time to find. Once I downloaded the data and added it into ArcMap, I needed a separate data dictionary to understand the attribute fields. The metadata unfortunately was not helpful in that regard. I was lucky to find a pdf through the website.

Overall The map reinforced that in the Humboldt County portion of Six Rivers, Douglas Fir is the most dominant tree type. Because of the spatial join, there are some issues with how accurate the resulting map is. There was some data lost.

Conclusions

It’s clear that there is value and importance in Old Growth Forests. Not just in tree species longevity but the overall biodiversity and health of the habitat that they are a part of. Unfortunately, a large part of those Forests have been lost through development or environmental factors. There are steps being taken to ensure their survival.

With this project there is room for improvement, ways to reach a more accurate map of old growth. I think the next steps that can be taken would be to do a map of the whole Six Rivers NF. Keeping all the tree types instead of querying out the ones chosen for this project. Then spatial joining that data with the late successional old growth polygon and comparing that area the estimation of 137,000 acres of old growth.

References
10 Year Report for the Northwest Forest Plan http://www.reo.gov/monitoring/reports/10yr-report/map-data/index.shtml 2016.12.09

A History of the Six Rivers National Forest http://www.foresthistory.org/ASPNET/Publications/region/5/six_rivers/contents.htm 2016.12.08

Beardsley, Debby, and Ralph Warbington. "Old Growth in Northwestern California National Forest." Pacific Northwest Research Station 491st ser. PNW.RP (1996): 1-56.

Bolsinger, Charles L., and Karen L. Waddell. "Area of Old-Growth Forest in California, Oregon, and Washington." Resource Bulletin 197th ser. PNW.RB (1993):

1-32.

"Business Plan for the Six Rivers National Forest." Forest Service-Pacific Southwest Region 068th ser. RS. MB (2006): 1-49. Print

Butz, Ramona J., and Hugh Safford. "A Summary of Current Trends and Probable Future Trends in Climate and Climate Driven Processes for the Six Rivers National Forest and Surrounding Lands." Six Rivers NF Climate Change Trend Assessment (2010): 1-18.

"Fire Management." U.S. Forest Service. 1-8. Print.

FRAP Mapping. CAL FIRE. http://frap.fire.ca.gov/data/frapgisdata-subset . 2016.12.07

Waddell, Karen. "PNW-FIADB User’s Manual." Forest Inventory and Analysis (2013): 1-271. Print.

Geospatial Data http://www.fs.usda.gov/main/r5/landmanagement/gis 2016.12.04

Humboldt County GIS Data Download http://humboldtgov.org/276/GIS-Data-Download 2016.12.04

Old Growth Forests in the Pacific Northwest, USA. Conservation Biology Institute. https://databasin.org/galleries/90e11cbab3724db2aa801e67643d9151 2016.12.07

Six Rivers National Forest. U.S. Department of Agriculture, Forest Service. http://www.fs.usda.gov/srnf/ 2016.12.01

"Six Rivers National Forest- Land and Resource Management Plan." (2013): 1-45. Print

USGS Earth Explorer. https://earthexplorer.usgs.gov/ 2016.12.11