December 1999

U.S. Department of the Interior 

Bureau of Land Management

June 2000

Assessment of Oak Woodland Resources 

in BLM’s Eugene District

Lane County, Oregon

Technical Note 406

Assessment of Oak Woodland Resources 

in BLM’s Eugene District

Lane County, Oregon

Technical Note 406

By:

David G. Chiller

Research Biologist, Pacific Wildlife Research Inc.

David G. Vesely

Senior Forest Ecologist, Pacific Wildlife Research Inc.

William I. Dean

Wildlife Biologist, Bureau of Land Management, Eugene District

June 2000

BLM/OR/WA/PL-00/052+6635

Eugene District Office

2890 Chad Drive

Eugene, OR 97440-2226



A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

ABSTRACT A B S T R A C T

Because of the significant loss of oak (Quercus

spp.) habitat and the subsequent increased value 

placed on oak woodlands for wildlife habitat, the 

preservation and restoration of native oak woodlands has become a priority for land managers and conservationists in the Western 

United States. In 1998, reconnaissance surveys were conducted on 13 oak woodland sites 

managed by the Bureau of Land Management’s 

(BLM’s) Eugene District in Lane County, 

Oregon. The sites were classified as either 

meadow-type communities or woodland-type 

communities; oak patches within the sites 

were delineated; and the topographic features, 

vegetation structure, and composition of the 

sites were characterized. Current conditions 

were then compared with conditions documented in historical records. In addition, the 

wildlife species most likely occurring on the 

sites were identified. Literature from oak woodland studies was then reviewed to determine 

whether certain management and restoration 

methods, such as eliminating conifer encroachment and thinning closed-canopy stands, would 

be effective in addressing conditions observed at 

the BLM sites.

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ACKNOWLEDGMENTS A C K N O W L E D G M E N T S

This work was part of a cooperative study, 

which involved the Oregon Department of 

Fish and Wildlife, The Nature Conservancy, 

Oregon and Washington Natural Heritage 

Program, and the Bureau of Land Management 

(BLM), to investigate oak woodland habitats. 

We would like to thank John Chatt, Carole 

Jorgensen, Lynn Larson, Cheshire Mayrsohn, 

and Chris Melotti for providing significant logistical support and encouragement throughout 

the development and implementation of this 

project. We would also like to thank Rebecca 

Goggans, Douglas Gomez, Joan Hagar, David 

Hibbs, Matt Hunter, Paula Larson, and Mike 

Reichenbach for their valuable contributions to 

an earlier draft of this report. Finally, we thank 

Eric Campbell and BLM’s Oregon State Office 

for supporting the publication and distribution 

of this assessment, making it more available 

to other resource managers.



A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

TABLE OF CONTENTS T A B L E O F C O N T E N T S

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Figures and Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

 Oak Woodlands: Past and Present. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

 Assessment Objectives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

 Project Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Site Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Site Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Oak Patch Delineation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

 Site Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

 Topography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

 Patch Composition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

 Additional Descriptive Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

 Oak Distribution Patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 Wildlife Habitat Associations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 Wildlife Species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

 Habitat Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

 Restoration and Management Literature Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Results and Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Overview of BLM Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Physiography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Plant Community Composition and Structure. . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Oak Growth and Regeneration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 Site Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

 Anthony Creek. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

 Bates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

 Cougar Mountain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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 Eagle’s Rest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

 Fox Hollow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

 Gilkey Creek. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

 Kloster Mountain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 Rattlesnake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 Sears Road. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 Seventy-Ninth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 Weiss Road. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 Wendling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

 Wills Road. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

 Oak Distribution Patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

 Regional Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

 Patch Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

 Effects of Fire Suppression. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

 Wildlife Habitat Associations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

 Species that Use Oak Woodlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

 Habitat Components of Oak Woodlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

 Restoration and Management Literature Review. . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

 Conifer Encroachment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

 Thinning of Closed-Canopy Stands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Summary and Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

 Vegetation Patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

 Wildlife Habitat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

 Mast Production. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

 Vegetation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

 Cavities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

 Patch Size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

 Oak Management Recommendations by Other Authors. . . . . . . . . . . . . . . . . . . . . . 44

Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

 List of Wildlife Species Potentially Occurring in Habitats Found 

 in the Surveyed Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
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FIGURES AND TABLES F I G U R E S A N D T A B L E S

Figures

Figure 1. Map of Lane County, Oregon, showing the distribution and location 

of the 13 survey sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 2a. Relationship between tree height and dbh for sampled oaks. . . . . . . . . . . . . . 20

Figure 2b. Relationship between tree age and height for sampled oaks. . . . . . . . . . . . . . 20

Figure 2c. Relationship between tree age and dbh for sampled oaks. . . . . . . . . . . . . . . . 20

Figure 2d. Relationship between growth rate and mean crown radius for sampled oaks. . 20

Figure 3. Typical spatial pattern of oaks and conifers in meadow and woodland sites. . 28

Tables

Table 1. List of surveyed sites, patch acronyms, and associated community types. . . . . . 6

Table 2. Physical descriptors of individual patches including units and 

methods/instruments used. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Table 3. Variables and methods used to characterize canopy layers within patches. . . . . 8

Table 4. Descriptive variables for tree composition of individual canopy layers. . . . . . . 8

Table 5. Summary of physical characteristics of surveyed patches. . . . . . . . . . . . . . . . . 13

Table 6. Summary of the most abundant tree cohorts occurring in canopy layers in 

each surveyed patch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 7. Summary of selected oak size characteristics for each surveyed patch. . . . . . . 16

Table 8. List of snags counts and characteristics for each surveyed patch. . . . . . . . . . . 17

Table 9. Percent occurrence of the most dominant shrubs in the surveyed patches. . . 18

Table 10. Percent occurrence of nonnative plants observed in the surveyed patches. . . . 18

Table 11. Growth and age information for sampled oak trees. . . . . . . . . . . . . . . . . . . . . 19

Table 12. Estimates of oak regeneration abundance in the surveyed patches. . . . . . . . . . 21

Table 13. Historical vegetation classifications for the surveyed sites. . . . . . . . . . . . . . . . 39

Table 14. Classification of surveyed sites based on site characteristics, degree

of conifer competition, and possible management actions. . . . . . . . . . . . . . . . 40

Table 15. Estimated annual acorn yields for the surveyed patches. . . . . . . . . . . . . . . . . 42



A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

INTRODUCTION I N T R O D U C T I O N

Oak Woodlands: Past 

and Present

The preservation and restoration of native 

oak (Quercus spp.) woodlands has recently 

become an important priority for land managers and conservationists in the western 

United States. This effort has been driven by 

a growing recognition of the significant loss of 

oak habitat and the subsequent “increased 

value placed on oak woodlands within the past 

20 years, for esthetics, wildlife habitat, watershed functioning, outdoor recreation” and 

other qualities (Pillsbury et al. 1997).

In western Oregon, oak woodlands in the 

lowlands and neighboring foothills of 

the Willamette Valley have been heavily 

influenced by human activity for centuries 

(Johannessen et al. 1971). Extensive annual 

fires set by Native Americans prior to immigration of settlers in the 1840’s, maintained 

open oak savannas and prairies and excluded 

tree species not adapted to frequent fire 

regimes (Cole 1977; Franklin and Dyrness 

1988). Euro-Americans practiced fire suppression in the Willamette Valley, which has subsequently promoted development of closedcanopy woodlands composed of Oregon 

white oak (Quercus garryana), Douglas-fir 

(Pseudotsuga menziesii), big-leaf maple (Acer 

macrophyllum), and other tree species 

(Thilenius 1968). Agricultural land practices, 

tree harvesting, and urban development also have 

led to widespread changes in Willamette Valley 

landscapes (Towle 1982). In addition, the establishment of introduced plant species within oak 

woodlands and grasslands (Habeck 1961) has 

greatly altered plant community composition.

Despite these changes, existing oak environments continue to represent important and 

unique habitat for numerous wildlife species. 

In California, over 300 vertebrate species use 

oak-dominated woodlands for various purposes (Block et al. 1990). Oak woodlands in the 

Willamette Valley have a greater avian species 

diversity than Douglas-fir and western hemlock 

(Tsuga heterophylla) habitats (Anderson 1972) 

and provide a higher density of cavity resources 

(Gumtow-Farrior 1991). Not only do oaks provide resources for numerous species of wildlife 

that are known to use acorns (Christisen and 

Korschgen 1955), but the leaves and twigs of 

oak trees and associated plants provide resources 

for an undetermined number of additional vertebrate and invertebrate species (Verner 1980; 

Pavlik et al. 1991; Keator 1998). Conservation, 

effective management, and recognition of the 

value of oak woodlands will therefore be important to maintaining this region’s wildlife diversity.

Oregon white oak, the most common oak 

species in the Willamette Valley and surrounding foothills, is most competitive at xeric or 

“poor” sites, which are areas that are dry and 

well-drained and areas that are droughty during 


A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

the summer and poorly drained during the wet 

season (Stein 1990). In the absence of fire, 

Oregon white oaks are normally outcompeted at mesic sites not subjected to intense 

drought in summer (Thilenius 1964, 1968; 

Stein 1990). Therefore, Oregon white oak is 

often confined to borders or edges between 

two communities (McCulloch 1940), such as 

dry meadows and mature forests.

Assessment

Objectives

In 1998, existing oak woodlands in the 

Bureau of Land Management’s (BLM’s) 

Eugene District in Oregon were identified 

and an assessment was conducted at selected 

sites. The objectives of the assessment were 

to:

❖ Describe the general physical and vegetation characteristics and conditions of 

each oak woodland and delineate woodland boundaries on aerial photos.

❖ Compare the current condition of selected sites with historical records using 

Oregon Natural Heritage Program vegetation classifications interpreted from 

General Land Office surveys conducted 

during the 1850’s.

❖ Identify wildlife species most likely associated with the oak woodlands in the 

region surveyed based on distributions 

and habitat requirements of oak associated species and assess general suitability 

of available oak habitat for potentially 

occurring species.

❖ Review literature from studies relating 

to oak woodland management and restoration studies relevant to conditions 

observed at the study sites.

This assessment was in support of the 

district’s efforts to preserve and effectively 

manage oak woodland habitats for associated 

wildlife species (USDI 1995).

Project Area

The oak woodlands surveyed lie within the 

McKenzie and South Valley Resource Areas 

(RA’s) administered by BLM’s Eugene District 

in Lane County, Oregon (Figure 1). Sites 

within the McKenzie RA occur on the approximate boundary of the Willamette Valley and 

Western Cascade physiographic provinces 

(Franklin and Dyrness 1988); those in the 

South Valley RA occur on the approximate 

boundary of the Willamette Valley and Coast 

Range provinces. These foothills are characterized by gentle slopes and valleys. Elevation of 

these sites was <2000 feet.

The climate of the Willamette Valley and surrounding foothills is temperate, with cool, wet 

winters and hot, dry summers. In Eugene, 

mean temperatures are 41 oF in January 

(min. 35 oF) and 67 oF in July (max. 81 oF); 

the average annual temperature is 53 oF. 

Annual precipitation averages 49.5 inches in 

Eugene, with more than 70 percent of rainfall 

occurring from November through March 

(Oregon Climate Service 1998).

The project area consists of a mosaic of vegetation characteristic of the pine-oak-fir 

(Pinus-Quercus-Pseudotsuga) vegetation zone 


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(Franklin and Dyrness 1988). This mosaic is 

composed of coniferous forests, oak woodlands, 

meadows, and forested wetland and riparian 

areas. Coniferous forests are dominated mainly 

by Douglas-fir with grand fir (Abies grandis), 

incense-cedar (Calocedrus decurrens), ponderosa pine (Pinus ponderosa), western redcedar 

(Thuja plicata) and western hemlock as associates. Big-leaf maple and Oregon white oak 

are common hardwood associates. Dominant 

understory species include dwarf Oregon grape 

(Berbis nervosa), California hazel (Corylus 

cornuta var. californica), salal (Gaultheria shallon), oceanspray (Holodiscus discolor), and 

sword fern (Polystichum munitum). Scattered 

grassy meadows on drier, south-facing slopes 

often contain Oregon white oak and pacific 

madrone (Arbutus menziesii), with poison 

oak (Rhus diversiloba), oceanspray, and hazel as 

the most common shrubs. Wetland and riparian areas are commonly dominated by big-leaf 

maple in addition to Oregon ash (Fraxinus 

latifolia), which often extends into less moist 

areas. California black oak (Q. kelloggi) is limited 

to the southern parts of the surveyed area 

(Franklin and Dyrness 1988; and personal 

observations).

Private and public lands are highly interspersed 

on the McKenzie and South Valley RA’s. 

Forestry and grazing have dominated land use 

on both public and private lands in the foothills. 

The floodplain of the Willamette River is the 

most densely populated region in Oregon.

Figure 1. Map of Lane County, Oregon, showing the distribution and location of the 13 survey sites.



A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

METHODS M E T H O D S

Site Selection

Clusters of oak trees in the McKenzie and 

South Valley RA’s were initially identified 

from field records and intra-agency communications. These locations were verified using 

aerial photos and field reconnaissance. The 

sites to be surveyed were then prioritized 

based on size and potential for timber and 

habitat management. One of the selected sites 

was actively managed for oak restoration prior 

to this survey. Selected sites were located 

within BLM parcels of forested land ranging 

from approximately 10-100 acres in size.

Site Classification

The sites were classified into two general types 

of oak communities:

❖ Meadow-type: Most oaks distributed along 

the perimeter of a small meadow having 

shallow soils, often on south-southwest 

aspects. Relatively larger oaks (height = 

30-60 feet) occurred along the meadow 

perimeter with smaller individuals (often 

with shrubby form, 15-20 feet in height) 

scattered in central regions of meadows and 

were usually the only tree species growing 

in this central area. Meadows and associated 

oaks were generally elliptical in shape, surrounded by a Douglas-fir-dominated conifer 

matrix.

❖ Woodland-type: Woodlands were characterized by a uniform cohort of oaks 

(height = 60-80 feet) that were usually in 

dominant canopy positions or codominant 

with Douglas-fir or Oregon ash. Woodland 

sites typically bordered or were embedded 

within Douglas-fir-dominated conifer 

forests or wetland areas consisting of 

Oregon ash and big-leaf maple.

Oak Patch Delineation

Between August 12 and September 24, 1998, 

13 sites were visited to delineate oak patches. 

At most sites, oak trees were distributed along 

a gradient of species composition: high concentrations of oaks arranged in small clusters 

or forming a ring around a meadow and gradually becoming less common in a forest matrix, 

usually dominated by Douglas-fir. Patch 

boundaries were based on five factors that 

were evaluated by the surveyor at each site:

1. Minimum patch area >1 acre.

2. Canopy composition: tree canopies at each 

patch were usually composed of more 

than 50 percent oak crowns.

3. Land ownership: non-BLM lands were 

excluded.

4. Topography: some boundaries were defined 

by sharp changes in slope or ridge lines.

5. “Compactness”: boundaries were adjusted 

to facilitate management within oak 

patches and surrounding forest.


A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Site Descriptions

The topographic features, vegetation 

structure,and composition were characterized 

Community	

	 Site	 Patch Acronym	 Type

Anthony Creek ANTH-1 Meadow

 ANTH-2

 ANTH-3

Bates BATES Meadow

Cougar Mountain COUG-1 Woodland

 COUG-2

Eagle’s Rest EAGL-1 Woodland

 EAGL-2

Fox Hollow FOX Woodland

Gilkey Creek GILK-1 Meadow

 GILK-2 

 GILK-3 

Kloster Mountain KLOS-1 Meadow

 KLOS-2

 KLOS-3

 KLOS-4

Rattlesnake RATT-1 Meadow

 RATT-2 

 RATT-3

Sears Road SEARS Woodland

Seventy-Ninth SEVENT Meadow

Weiss Road WEISS Meadow

Wendling WEND-1 Meadow

 WEND-2

Wills Road WILLS Woodland

in 25 oak patches, which are listed in 

Table 1.

Table 1. List of surveyed sites, patch acronyms, and associated community types.


A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Topography

Patch-level metrics (e.g., patch area, aspect, 

slope, elevation) and the location of patch 

centers including the respective units, methods, 

and instruments used, are shown in Table 2.

Patch Composition

Canopy 

A modified form of guidelines from Cadwell 

(1998) was used to classify the vertical strata of tree canopies. Tree cover for each patch 

was divided into a maximum of three layers 

Table 2. Physical descriptors of individual patches including units and methods/instruments used.

with at least a one-third difference in height 

between successive layers. For each layer, the 

absolute percent canopy cover for the patch, 

average top height of the layer, and total 

number of trees per acre were determined 

(Table 3). For the bottom canopy layer, trees 

<10 feet in height were not counted. To 

characterize the composition of each layer, 

the percent cover of the five most dominant 

species cohorts (species in an individual size 

class) with a relative canopy layer cover 

>5 percent was recorded (Table 4). 

Additional species observed were noted.

Variable	 Unit	 Method/Instrument	

Area Nearest whole acre Rangefinder and hip-chain

Aspect (average) Degrees Compass

Slope (average) Degrees Clinometer

Elevation Nearest 50-foot interval Topographic map 

Location UTM-Lat/Long GPS


A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 3. Variables and methods used to characterize canopy layers within patches (three layers 

maximum).

Table 4. Descriptive variables for tree composition of individual canopy layers.

Snags

The following data were recorded for each 

snag (completely dead tree) >10 inches dbh 

within each patch:

1. Type: either oak or other species.

2. Diameter class: 10-20 inches or >20 

inches.

3. Structural classifications: a. Hard – trees 

with most of their branches and bark 

Variable	 Unit	 Method/Instrument	

Canopy cover Percent of patch cover Ocular estimate, absolute 

 for each layer

Height Nearest 10 feet Average top of layer, 

 rangefinder and clinometer

Trees per acre Nearest whole number 100 percent tree count

Percent of layer Percent (multiple of 5) Relative abundance of top 

 five species by diameter class 

 (min. 5 percent)

Diameter at breast height Diameter classes (inches): Ocular estimate; dbh tape, 

(dbh) 0-5, 5-10, 10-15, 15-20, tape stick 

 20-30, 30-50

Variable	 Unit	 Method/Instrument	

present and little sign of decay; b. 

Soft – trees commonly with tops 

broken off, lacking branches and 

bark (except Pseudotsuga menziesii

and Abies grandis), with extensively 

decayed sapwood and heartwood 

(Parks et al. 1997).


A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Shrubs and Nonnative Plants

The five most common woody shrubs were 

recorded, along with percent of patch cover 

(nearest 5 percent). The presence of certain 

nonnative plants common to these habitats 

was also noted.

Oak Growth and Regeneration

To understand factors affecting oak growth in 

each site, an additional set of descriptors and 

variables was collected:

1. The general relative soil characteristics—

moisture level, depth, and the presence 

of rocky outcrops—were noted.

2. To assess environmental and competitive factors potentially affecting oak 

growth, as well as the quality and 

quantity of wildlife habitat, the general 

form of oaks according to the degree of 

openness/width of tree crowns and locations within the patch where form varied 

were noted.

3. The relative abundance of oak regeneration (oak trees with dbh <3 inches and 

height <10 feet) in each patch was noted 

using ocular estimation:

a. Absent.

b. Rare, ~1-20 stems per acre.

c. Common, ~21-50 stems per acre.

d. Abundant, >50 stems per acre. 

4. In addition, increment core samples 

were obtained from one or two trees at 

each patch. Open-form trees were cored 

to study oak diameter growth rates in the 

absence of competition. When open-form 

trees were not present, cores were taken 

from relatively older trees with the widest crowns, and consequently, the least 

(relative) amount of competition from 

neighbors. Core samples were taken at 

breast height and were used to estimate 

growth rates or rings per inch (RPI) and 

age (either by counting growth rings or 

using RPI x tree radius at breast height if 

cores were not complete). Height, diameter at breast height, and mean crown 

radius were also measured for each cored 

tree. In addition, at two of the meadowtype communities, a single tree was 

harvested along with numerous shorter, 

shrubby clusters of oak stems. The complete cross section produced from these 

stems provided a more accurate estimate 

of age and growth rates in these thin, 

slow-growing stems.

Additional Descriptive 

Information

One or two photographs were taken (using a 

35mm SLR camera with a 28mm lens) and 

maps were sketched of each patch to provide 

additional visual references of oak distribution. 

Evidence of grazing (e.g., presence of fencing) 

and tree harvesting, as well as off-road use, 

vandalism, and dumping, was recorded at each 

location. In some sites, searches were performed 

outside of the patch boundaries to determine 

the presence, distribution, and general condition 

of neighboring oak communities and to assist in 

the understanding of the vegetation history at 

that site.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Oak Distribution 

Patterns 

A combination of survey information and the 

interpretation of historic land survey records 

was used to characterize the vegetation history 

and trends occurring at each site. During the 

1850’s, the U.S. General Land Office (GLO) 

conducted land surveys in the Willamette 

Valley to designate township and sections 

and determine lands suitable for settlement. 

Experienced surveyors used large “bearing” or 

“witness” trees to mark township and sectional 

boundaries in addition to making general vegetation and environmental descriptions (Habeck 

1961). Christy et al. (1996) have used the 

transcriptions and plat maps of the GLO surveyors and soil maps to create classifications of 

historic vegetation types for the surveyed areas 

within Lane County. These classifications have 

been transcribed into databases, which can be 

used to produce geographic information system (GIS) maps of historical vegetation (see 

Christy et al. 1996 for detailed protocol). 

Two vegetation classifications were available 

from these maps for characterizing historic 

vegetation at the oak sites: major vegetation 

types and subcategories of these major types. 

Subcategory information was not available for 

all sites and GLO survey information was 

completely lacking for two sites. The four 

major types of vegetation occurring at or 

near sites are listed below with definitions 

according to Christy et al. (1997):

❖ Closed forest upland: Distance to witness 

trees (large, marker trees used to establish 

boundaries of townships and sections) was 

<66 feet, typically <33 feet. Stands may 

include fire-sensitive species such as cedar, 

hemlock, and maple.

❖ Woodland: Distance to witness trees mostly 66-132 feet. Stands usually lack cedar, 

hemlock, and maple.

❖ Savanna: Openings with grass, fern, hazel, 

and shrub oak understory. Distance to witness trees mostly >132 feet.

❖ Prairie: Distance to witness trees mostly 

132-528 feet. Understory with grass or 

fern, with no reference to dense shrub 

growth.

Wildlife Habitat 

Associations

Wildlife Species 

To identify species most likely occurring in 

the surveyed sites in Lane County, Oregon, 

a list of wildlife species associated with the 

observed habitats was compiled using information from Brown (1985) and Csuti et 

al. (1997). Three plant communities were 

selected from Brown (1985) that most closely 

represented those at the surveyed sites: dryhillside/grass-forb, deciduous-hardwood; and 

conifer-hardwood. In order to focus on species 

most strongly associated with the selected community types, only species breeding in these 

habitats were listed. The use of edge habitats 

and specific information on required habitat 

structural components (snags and cavities) for 

the selected species were also noted. Because 
11

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Brown (1985) does not directly specify species associated with oaks, habitat information 

from Csuti et al. (1997) was included to help 

identify which of the selected species are 

known to use oak woodlands. Some of the 

limited oak-habitat relationship information 

for the Willamette Valley was included by 

listing relative bird abundance information 

from Hagar and Stern (1997). From this list 

and other sources, ten species that are commonly associated with oaks were chosen and 

the use of oak habitat for five of these species 

was described.

Formal wildlife surveys were not conducted; 

however, any sign or direct observation of 

wildlife species was noted during vegetation 

surveys.

Habitat Components

Oak-related literature was reviewed to evaluate 

the relationships between animal populations 

and Oregon white oak plant communities. 

Acorn production in each patch was estimated 

using relationships described by Goodrum et 

al. (1971). Using counts of trees per acre and 

the relative abundance of oak cohorts (dbh class) 

in each canopy layer, as well as additional field 

notes, the number of trees was estimated by size 

class at each surveyed patch. The mast production was then calculated for the size classes producing acorns according to the following approximated yields from Goodrum et al. (1971; 

table 2): 10-15 inches dbh = 5.48 pounds; 

15-20 inches = 11.05 pounds; 20-25 inches 

= 16.65 pounds; 25-30 inches = 20.5 pounds.

Restoration 

and Management 

Literature Review

Oak woodland management and restoration 

literature that addressed the specific conditions observed at the surveyed sites was 

reviewed in order to aid future management 

decisions for these areas.

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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

RESULTSR E S U L T S A N D D I S C U S S I O N AND DISCUSSION

Overview of BLM Sites

Physiography

The BLM sites surveyed ranged from 750 

to 2,000 feet above sea level (Table 5). The 

sites most often occurred on xeric, south and 

southwest hill slopes, although some sites (e.g., 

Eagle’s Rest, Fox Hollow) occurred in lower topographic positions and had moist or wet soils.

Plant Community 

Composition and Structure

Dominant tree canopy positions in woodlandtype patches and adjacent to meadow-type 

patches were most often occupied by Douglasfir, with incense-cedar and Oregon white oak 

occasionally codominant (Table 6). Pacific 

madrone was often observed on xeric sites.

Table 5. Summary of physical characteristics of surveyed patches (N= 25 for all variables).

Elevation (feet)	 Slope (°)	 Aspect (°) Acres	

Mean 1,264.0 18.9 187.6 2.6

Max. 2,000.0 47.0 290.0 5.0

Min. 750.0 5.0 72.0 1.0

Oregon ash, grand fir, and big-leaf maple were 

also common.

Oregon white oak occurred in small patches 

(maximum area = 5 acres) at the 13 BLM 

sites, and oak crowns usually formed a minor 

component of the overall canopy (mean = 

18 percent cover, max. = 54 percent cover) 

(Table 7). Oak trees >15 inches dbh were 

rare at the BLM sites and dry sites on south 

and southwest aspects were dominated by a 

cohort of shrubby oaks <5 inches dbh.

Snags were uncommon structural features 

in the surveyed BLM woodlands (Table 8). 

The greatest total density measured was 8.5 

snags/acre (COUG-1) and snags >20 inches 
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

dbh were very rare (maximum observed density = 0.75/acre). Although the number or 

volume of dead branches in the surveyed sites 

was not measured, it was subjectively estimated that dead branches on live oak trees represented a considerable fraction of the small 

diameter (<10-inch diameter) cavity nesting 

substrate in these woodlands.

Poison oak was the most frequently observed 

shrub (88 percent of patches) at oak patches 

(Table 9). Oceanspray and Himalayan blackberry (Rubus discolor) were also observed at 

more than half the patches surveyed.

Most sites were occupied by one or more 

plant species listed by the BLM as nonnative 

plants (Table 10); however, only Himalayan 

blackberry and Scotch broom were abundant 

within oak patches.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 6. Summary of the most abundant tree cohorts (based on species and size) occurring in canopy layers in 

each surveyed patch. Patches are listed according to community type: M= meadow, W= woodland. Cohort 1 and 

2 (C1 and C2) represent the species of the two most dominant tree cohorts for each layer; a dashed line indicates 

that either only one species occurred in the top layer or the canopy consisted of only two layers (top and bottom). 

Multiple cohorts indicate equal dominance. ABGR= grand fir; ACMA= big leaf maple; ARME = Pacific madrone; 

CADE= incense-cedar; FRLA = Oregon ash; PSME = Douglas-fir; QUGA = Oregon white oak.

ANTH-1 M PSME CADE QUGA ARME QUGA QUGA

ANTH-2 M ARME ARME - - QUGA ARME

ANTH-3 M PSME - ARME ARME QUGA ARME/PSME

BATES M PSME PSME QUGA ARME QUGA QUGA

GILK-1 M PSME PSME QUGA QUGA QUGA CADE

GILK-2 M PSME CADE CADE PSME QUGA PSME

GILK-3 M PSME PSME QUGA CADE/PSME QUGA PSME

KLOS-1 M PSME - - - QUGA ARME/PSME

KLOS-2 M PSME CADE QUGA ACMA/ARME/CADE QUGA QUGA

KLOS-3 M PSME - QUGA ACMA/ARME/CADE QUGA QUGA/PSME

KLOS-4 M PSME - QUGA ARME/QUGA QUGA ARME/PSME

RATT-1 M PSME PSME QUGA PSME QUGA PSME

RATT-2 M PSME PSME QUGA ACMA/PSME QUGA ACMA/PSME

RATT-3 M PSME PSME QUGA QUGA QUGA ACMA/PSME

SEVENT M PSME - QUGA ARME/QUGA/PSME QUGA QUGA

WEISS M PSME PSME PSME PSME PSME QUGA

WEND-1 M QUGA QUGA - - QUGA QUGA

WEND-2 M PSME - QUGA QUGA QUGA QUGA 

COUG-1 W PSME ABGR/PSME QUGA ABGR ABGR QUGA

COUG-2 W CADE QUGA - - ABGR CADE

EAGL-1 W QUGA QUGA - - FRLA ABGR/PSME/QUGA

EAGL-2 W QUGA PSME PSME FRLA FRLA PSME 

FOX W PSME PSME PSME ACMA/FRLA/PSME PSME QUGA

SEARS W PSME PSME QUGA QUGA PSME QUGA

WILLS W PSME PSME QUGA QUGA QUGA QUGA

Canopy Layer

	 	 Community 	 Top	 	 Middle	 Bottom	 	

	 Patch	 Type	 C1	 C2	 C1	 C2	 C1	 C2	
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 7. Summary of selected oak size characteristics for each surveyed patch. Patches are listed according 

to community types: M= meadow, W= woodland. For each patch, the size class, percent cover for the entire 

patch, and the respective canopy layer height values are given for the oak cohort with the greatest patch cover 

and the largest size class (dbh).

Community	 Area	 Oak Cohort with Greatest Patch Cover Oak Cohort with Largest Diameter Class

	 Patch	 Type	 (acres)

	 	 	 	 dbh Class	 Percent	 Layer Height 	 dbh Class	 Percent	 Layer Height 

	 	 	 	 (in)	 Cover	 (feet)	 (in)	 Cover	 (feet)	

ANTH-1 M 1 0-5 14 20 10-15 1 40

ANTH-2 M 2 5-10 3 30 10-15 1 30

ANTH-3 M 2 5-10 4 30 5-10 4 30

BATES M 3 0-5 15 25 5-10 12 40

GILK-1 M 2 10-15 12 50 10-15 12 50

GILK-2 M 1 5-10 3 30 15-20 2 70

GILK-3 M 2 10-15 8 60 10-15 8 60

KLOS-1 M 3 5-10 8 50 5-10 8 50

KLOS-2 M 3 0-5 18 20 5-10 2 40

KLOS-3 M 5 0-5 8 20 5-10 4 40

KLOS-4 M 3 0-5 21 20 10-15 1 40

RATT-1 M 4 5-10 8 40 10-15 2 40

RATT-2 M 3 10-15 8 30 10-15 4 50

RATT-3 M 4 5-10 8 20 10-15 4 40

SEVENT M 2 0-5 54 15 5-10 14 40

WEISS M 3 15-20 2 70 15-20 2 70

WEND-1 M 2 5-10 21 35 10-15 3 35

WEND-2 M 3 5-10 14 30 5-10 14 30

COUG-1 W 2 10-15 21 70 15-20 7 70

COUG-2 W 2 10-15 21 80 10-15 21 80

EAGL-1 W 1 10-15 45 80 10-15 45 80

EAGL-2 W 2 10-15 48 80 15-20 8 80

FOX W 2 5-10 18 40 10-15 7 70

SEARS W 5 10-15 28 80 15-20 3 80

WILLS W 2 10-15 28 80 15-20 14 80
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 8. List of snag counts and characteristics for each surveyed patch. Patches are listed according to community 

type: M = meadow and W = woodland. Size classes are dbh (inches). Refer to Methods section for definition of 

hard and soft characteristics.

Total 7.0 2.0 22.0 2.0 19.0 14.0 26.0 13.0 105.0

Mean 0.3 0.1 0.9 0.1 0.8 0.6 1.0 0.5 4.2

ANTH-1 M 0 0 0 0 0 0 0 0 0

ANTH-2 M 0 0 0 0 0 0 0 0 0

ANTH-3 M 0 0 0 0 0 0 0 0 0

BATES M 0 0 0 0 0 0 3 4 7

COUG-1 W 0 0 0 0 3 1 11 2 17

COUG-2 W 1 0 1 0 7 0 1 0 10

EAGL-1 W 0 0 4 0 0 0 2 0 6

EAGL-2 W 2 0 3 0 0 0 0 0 5

FOX W 0 0 1 0 1 2 1 3 8

GILK-1 M 0 0 0 0 0 1 0 0 1

GILK-2 M 0 0 0 0 0 0 0 0 0

GILK-3 M 0 0 0 0 2 5 0 0 7

KLOS-1 M 0 0 0 0 0 0 0 0 0

KLOS-2 M 0 0 0 0 0 0 0 0 0

KLOS-3 M 0 0 0 0 0 0 0 0 0

KLOS-4 M 0 0 0 0 0 0 0 0 0

RATT-1 M 0 1 0 0 0 0 0 4 5

RATT-2 M 1 0 0 0 0 0 0 0 1

RATT-3 M 0 0 0 0 2 0 2 0 4

SEARS W 2 1 8 2 0 1 3 0 17

SEVENT M 0 0 0 0 1 0 0 0 1

WEISS M 0 0 1 0 2 2 1 0 6

WEND-1 M 0 0 0 0 0 0 0 0 0

WEND-2 M 0 0 0 0 0 1 0 0 1

WILLS W 1 0 4 0 1 1 2 0 9

Oaks	 Other Species	

	 	 Community	 Hard	 Soft	 Hard	 Soft

	 Patch	 Type	 10-20	 >20	 10-20	 >20	 10-20	 >20	 10-20	 >20	 Total	
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Poison oak 88 (22)

Oceanspray 60 (15)

Himalayan blackberry 56 (14)

California hazel 44 (11)

Orange honeysuckle 40 (10)

Tall Oregon grape 36 (9)

Trailing blackberry 36 (9) 

Common snowberry 32 (8)

Table 9. Percent occurrence of the most dominant shrubs in the surveyed patches. Numbers in parentheses = 

number of patches. Total number of patches surveyed = 25.

Shrub	 Percent Occurrence	

St. John's wort 64 (16)

Tansy ragwort 60 (15)

Himalayan blackberry 56 (14)

Bull thistle 40 (10)

Scotch broom 32 (8) 

Evergreen blackberry 32 (8)

Canada thistle 8 (2)

Table 10. Percent occurrence of nonnative plants observed in the surveyed patches. Numbers in parentheses = 

number of patches. Total number of patches surveyed = 25.

Nonnative Plant	 Percent Occurrence

Oak Growth and Regeneration

Diameter (dbh), height, diameter growth 

(RPI), and estimated ages were measured for 

20 sample Oregon white oaks located on the 

BLM sites (Table 11). On average, diameter 

growth was 21.0 RPI (range = 7.8-45.8). 

Thilenius (1964) reported mean diameter 

growth (RPI) =12.5 among “forest-form” 

or closed canopy trees (12-21 inches dbh). 

Stein (1990) reported that 16-20 RPI is typical among Oregon white oaks. Relationships 

between sample tree attributes are represented in Figures 2A-D. Estimates of oak 

regeneration for each patch are shown in 

Table 12.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 11. Growth and age information for sampled oak trees. Patches are listed according to community 

type: M = meadow and W = woodland. dbh= diameter at breast height, RPI = rings per inch. The #1 and 

#2 following a patch name indicates two different cores taken at the same patch.

ANTH-3 M 8.5 32 22.2 59 9.5

BATES M 11.0 30 21.3 88 8.3

GILK-2 M 17.0 64 13.0 111** 17.3

GILK-3 M 13.0 75 27.4 178** 10.0

KLOS-1 M 11.5 50 12.3 58 9.5

KLOS-3* M 3.5 21 45.8 50

KLOS-4 M 7.0 30 19.0 53 7.5

RATT-3 M 16.0 35 8.3 67** 14.0

SEVENT M 14.0 42 26.7 187** 8.8

WEISS (#1) M 11.5 28 7.8 39 12.5

WEISS (#2) M 15.0 70 18.0 100 10.8

WEND-2 (#1) M 7.5 30 22.1 50 5.0

WEND-2* (#2) M 3.0 24 33.6 47

COUG-1 W 19.5 62 25.7 251** 10.8

COUG-2 W 22.0 70 15.0 165** 9.3

EAGL-1 W 12.5 85 22.5 134 13.0

EAGL-2 W 15.5 80 16.7 130** 13.3

FOX W 12.0 65 28.4 170** 8.8

SEARS W 21.0 62 15.8 166** 12.8

WILLS W 14.5 85 17.8 129** 9.

 Mean 12.8 52.0 21.0 68 10.6

* cuttings or very small stems for which canopy radii were not measured. ** age was estimated (rings per inch x radius at breast height).

	 	 Community	 dbh	 Height	 	 Estimated	 Mean Crown

	 Patch	 Type	 (inches)	 (feet)	 RPI	 Age (years)	 Radius (feet)	
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

A

90

80

70

60

50

40

30

20

10 20

10

0 15

0

5 25

Tree height (feet)

dbh (inches

C

300

250

200

150

100

10 20

50

0 15

0

5 25

Estimated Age (years)

dbh (inches)

B

300

250

200

150

100

40 80

50

0 60

0

20 100

Estimated Age (years)

Height (feet)

D

30

25

20

15

10

15

5

0 10

0

5 20

Rings per inch

Mean crown radius (feet)

Figures 2A-D. Relationships between (A) tree height and dbh, (B) tree age and height, (C) tree age and 

dbh, and (D) growth rate (rings per inch) and mean crown radius for sampled oaks. 
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Table 12. Estimates of oak regeneration abundance (oak stems with dbh <3 inches 

and height <10 feet) in the surveyed patches. Patches are listed according to community type: M = meadow, W = woodland. Rare ~1-20 stems per acre; common 

~21-50 stems per acre. Area estimated to nearest acre.

ANTH-1 Rare M 1

ANTH-2 Absent M 2

ANTH-3 Absent M 2

BATES Common M 3

GILK-1 Common M 2

GILK-2 Common M 1

GILK-3 Common M 2

KLOS-1 Rare M 3

KLOS-2 Common M 3

KLOS-3 Common M 5

KLOS-4 Common M 3

RATT-1 Rare M 4

RATT-2 Rare M 3

RATT-3 Rare M 4

SEVENT Rare M 2

WEISS Rare M 3

WEND-1 Rare M 2

WEND-2 Common M 3

COUG-1 Rare W 2

COUG-2 Rare W 2

EAGL-1 Rare W 1

EAGL-2 Rare W 2

FOX Common W 2

SEARS Rare W 5

WILLS Common W 2

	 	 Oak Community	 Area	

	 Patch	 Regeneration	 Type	 (acres)	
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Site Descriptions

Anthony Creek

Site: south aspect; soil appears shallow in 

meadow; xeric.

Oak distribution: three clusters of small 

(<2-acre) meadow-type communities.

Vegetation structure: top canopy layers dominated by Douglas-fir, Pacific madrone, and incensecedar; oak canopy cover ~14 percent; oaks >5 

inches dbh are rare (<5 percent cover). 

Oak growth rate: sample tree height was 32 

feet (dbh = 8.5 inches) at 59 years.

Regeneration: oak seedlings were very rare; some 

sprouts on fire-scarred trees were observed; 

conifer regeneration is rare.

Management issues: none noted.

1850’s land cover: closed upland forest.

Bates

Site: hilltop position; steeper slopes than 

average; xeric to mesic conditions.

Oak distribution: single meadow-type community; approximately 3 acres; oaks interspersed with madrone and Douglas-fir.

Vegetation structure: top canopy layer dominated by Douglas-fir; oak canopy cover ~15 percent; largest oaks are in 10- to 15-inch dbh class; 

dense shrub layer; poison oak cover >90 percent.

Oak growth rate: sample tree height was 30 

feet (dbh = 11.0 inches) at 88 years.

Regeneration: abundant vegetative sprouts 

from live trees. 

Management issues: sensitive plant area.

1850’s land cover: woodland.

Cougar Mountain

Site: south aspect; hillside position; moist soil 

(spring observed near Coug-2).

Oak distribution: two small (2-acre) woodland-type communities; oaks also occurred on 

adjacent private lands to the east at Coug-1.

Vegetation structure: top canopy layer dominated by Douglas-fir, incense-cedar, grand fir, 

and oak; oak canopy cover ~21 percent; largest 

oaks are in 25- to 30-inch dbh class; conifer 

succession apparent; Himalayan blackberry 

cover >20 percent.

Oak growth rate: sample tree #1 height was 

62 feet (dbh = 19.5 inches) at ~250 years; 

sample tree #2 height was 70 feet (dbh = 22.0 

inches) at ~165 years.

Regeneration: very rare oak reproduction 

observed; conifer regeneration is common.

Management issues: compacted soils from 

bike trail (Coug-1); old fencing (Coug-2).

1850’s land cover: prairie; closed upland forest.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Eagle’s Rest

Site: northwest aspect; lower slope position; 

seasonal wetlands observed.

Oak distribution: two small (<2-acre) woodland-type communities; oaks continue to adjacent private lands.

Vegetation structure: top canopy layer is 

dominated by oak and Douglas-fir; oak canopy 

cover ~50 percent; largest oaks are in 20- to 

25-inch dbh class; numerous dead branches 

on live trees; Himalayan blackberry cover 

>90 percent at Eagl-2.

Oak growth rate: sample tree #1 height was 85 

feet (dbh = 12.5 inches) at 134 years; sample 

tree #2 height was 80 feet (dbh = 15.5 inches) 

at ~130 years.

Regeneration: oak reproduction is rare; Oregon 

ash and Douglas-fir regeneration is common.

Management issues: fencing on west property 

line at Eagl-2; blackberry density indicates 

possible grazing; minor amounts of garbage.

1850’s land cover: described as “mountainous 

and unfit for habitation.”

Fox Hollow

Site: lower slope-riparian position; moist soil.

Oak distribution: single, small (~2-acre) woodland-type community; a reconnaissance of 

neighboring areas revealed scattered oaks (height 

range 30-70 feet, 5-15 inches dbh), one massive individual (approximately 26 inches dbh) 

is located approximately 200 feet south of the 

patch across a small stream.

Vegetation structure: top canopy layer dominated by Douglas-fir; oak canopy cover ~18 percent; largest oaks are in 15- to 20-inch dbh class; 

this was the only BLM site where California 

black oak was observed (Quercus kelloggi), representing approximately 20 percent of all oaks 

at this site; oaks in middle and bottom canopy 

position appeared to be of low vigor; conifer 

succession apparent; dense shrub layer.

Oak growth rate: sample tree height was 65 

feet (dbh = 12.0 inches) at ~170 years.

Regeneration: oak seedlings common in canopy 

gaps; conifer regeneration is also common.

Management issues: insect infestation problem 

on oak foliage.

1850’s land cover: woodlands and forests 

composed of Douglas-fir, chinquapin, and 

madrone on south slopes; Douglas-fir and bigleaf maple on north slopes; also incense-cedar, 

oak, grand fir, western redcedar, Pacific yew, 

red alder, and pacific dogwood.

Gilkey Creek

Site: south-facing slopes; dry soils in meadows.

Oak distribution: three small (<2-acre) meadow-type communities; oaks continue to bordering private lands at each patch.

Vegetation structure: top-canopy dominated 

by Douglas-fir, oak canopy cover ~12 percent; 

largest oaks in15- to 20-inch dbh class; majority 
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of oaks 10 to15 inches dbh; relatively tall (30- 

to 60-foot) oaks in meadow center at Gilk-1; all 

trees overtopped in Gilk-2.

Oak growth rate: sample tree #1 height was 64 

feet (dbh = 17.0 inches) at ~111 years; sample 

tree #2 height was 75 feet (dbh = 13 inches) 

at ~178 years.

Regeneration: common, mainly vegetative 

sprouting; conifer regeneration is common.

Management issues: compacted off-road trails 

(Gilk-1 and -2).

1850’s land cover: savanna and prairie bordering closed forest upland.

Kloster Mountain

Site: steep hillside meadows, with south aspect 

dry soils and numerous rocky outcrops.

Oak distribution: four meadow-type communities (<5 acres); embedded in a conifer matrix.

Vegetation structure: upper canopy dominated 

by Douglas-fir and some incense cedar; oak 

canopy cover ~21 percent; largest oaks 10-15 

inches dbh; oaks >10 inches dbh rare (<10 

percent cover).

Oak growth rate: sample tree #1 height was 

50 feet (dbh = 11.5 inches) at 58 years; sample #2 height was 21 feet (dbh = 3.5 inches) 

at 50 years; sample tree #3 height was 30 feet 

(dbh 7.0 inches) at 53 years.

Management issues: minor amount of logging 

operation debris.

Regeneration: common, mainly vegetative 

sprouting.

1850’s land cover: unclassified.

Rattlesnake

Site: upslope meadows varying in aspect.

Oak distribution: three meadow-type communities (<4 acres); reconnaissance south of Ratt2 revealed three small oak clusters in openings 

of ~0.75 acres (height range 30-50 feet, with 

one individual >80 feet, ~25 inches dbh; two 

clusters were likely on private land).

Vegetation structure: upper canopy dominated by Douglas-fir; oak canopy cover ~8 percent; largest oaks 25-30 inches dbh, but rare 

(<1 percent cover); majority of oaks growing 

under conifers.

Oak growth rate: sample tree height was 35 

feet (dbh = 16.0 inches) at ~67 years.

Management issues: sensitive plant site (Ratt-1).

Regeneration: oak and conifer regeneration 

are rare.

1850’s land cover: woodland and closed forest upland.

Sears Road

Site: lower slope bordering forested uplands, 

riparian area, and open savanna.

Oak distribution: single woodland-type 

community (~5 acres) merging with open 

grassland/savanna.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Vegetation structure: upper canopy dominated 

by Douglas-fir; oak canopy cover ~28 percent; 

large open grown oaks (30-40 inches dbh; 

<1 percent cover) overtopped by conifers 

at woodland/savanna edge; Himalayan blackberry cover (>90 percent cover) mainly under 

closed canopy woodland.

Oak growth rate: sample tree height was 62 feet 

(dbh = 21.0 inches) at ~166 years.

Management issues: fenceline on north-south 

property boundary.

Regeneration: oak regeneration is rare; conifer 

regeneration is common.

1850’s land cover: prairie.

Seventy-Ninth

Site: hillside meadow with northwest aspect; 

well-drained soils; embedded in forested uplands.

Oak distribution: single long thin meadow-type 

community (could be classified as unique woodland-type with shrub-form oaks) (~2 acres); ~25 

oaks (50-70 feet) observed in canopy gap 100 

yards northeast of surveyed patch.

Vegetation structure: upper canopy dominated 

by Douglas-fir; oak canopy cover ~54 percent; 

majority of trees with thin shrubby stems; 

largest oaks are 10-15 inches dbh; dense shrub 

layer (oceanspray cover ~70 percent).

Oak growth rate: sample tree height was 42 feet 

(dbh =14.0 inches) at ~187 years.

Management issues: water line at extreme east 

end of patch (exact property line not defined).

Regeneration: oak regeneration is rare; conifer 

regeneration is common.

1850’s land cover: closed forest upland.

Weiss Road

Site: lower slope meadow; bordering riparian 

area.

Oak distribution: single meadow-type community (~3 acres total); adjoining private land 

to north, which contains oaks with large relic 

oak snag.

Vegetation structure: upper canopy dominated 

by Douglas-fir; oak canopy cover ~2 percent, 

largest oaks are in 20- to 25-inch dbh class.

Oak growth rate: sample tree #1 height was 

28 feet (dbh = 11.5 inches) at 39 years; sample 

tree #2 height was 70 feet (dbh = 15.0 inches) 

at 100 years.

Management issues: site adjacent to logging 

road; dumping along road near patch.

Regeneration: oak regeneration is rare; conifer 

regeneration is common.

1850’s land cover: woodland.

Wendling 

Site: lower slope position; dry soils.

Oak distribution: two meadow-type communities (<3 acres).
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Vegetation structure: upper canopy dominated 

by Douglas-fir and oak; oak canopy cover 

~21 percent, largest oaks 15-20 inches dbh; 

management activities prior to surveys included conifer snag creation and removal of dense 

scotch broom cover.

Oak growth rate: sample tree #1 height was 

30 feet (dbh = 7.5 inches) at 50 years; sample 

tree #2 height was 24 feet (dbh = 3.0 inches) 

at 47 years.

Management issues: patches adjacent to road.

Regeneration: oak regeneration is rare; conifer 

regeneration is common.

1850’s land cover: woodlands and forests 

composed of Douglas-fir, chinquapin, and 

madrone on south slopes; Douglas-fir and bigleaf maple on north slopes; also incense-cedar, 

oak, grand fir, western redcedar, Pacific yew, 

red alder, and pacific dogwood.

Wills Road

Site: lower slope-riparian position; seasonally 

wet soil.

Oak distribution: small (<2-acre) single open 

woodland-type community; scattered oaks 

(height = 20–70 feet) bordering conifer matrix 

in canopy openings.

Vegetation structure: upper canopy dominated 

by Douglas-fir; oak canopy cover ~28 percent; 

largest oaks 25-30 inches dbh.

Oak growth rate: sample tree #1 height was 

85 feet (dbh = 14.5 inches) at ~129 years.

Management issues: evidence of oak harvesting near patch (1 stump 10-15 inches dbh).

Regeneration: oak regeneration is common; 

conifer regeneration is common. 

1850’s land cover: woodland and closed forest upland.

Oak Distribution 

Patterns

Regional Level

Most Oregon forests are dominated by 

conifers. Hardwoods often function as pioneer species or are confined to local niches 

(Franklin and Dyrness 1988). In western 

Oregon, oak woodlands are concentrated in 

the interior valleys (Franklin and Dyrness 

1988) where larger, fire-resistant oaks were 

able to survive the frequent fires that eliminated younger trees, creating open savanna and 

prairies in many areas (Thilenius 1968). The 

increase in closed canopy conditions in oak 

woodlands resulting from active fire suppression often favors seedling growth of conifers 

such as Douglas-fir (Barnhart et al. 1987). 

Several authors (Sprague and Hansen 1946; 

Habeck 1961; Thilenius 1964; Franklin and 

Dyrness 1988) have discussed potential climax 

communities succeeding oaks under continued 

fire control. In general, they conclude that the 

climax community is most likely conifer forest dominated by grand fir and/or Douglas-fir; 

however, this will vary according to specific 

conditions and existing vegetation.
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

be “stable and self-perpetuating” (Thilenius 

1968; Lorimer 1993 and references therein). In 

certain communities of the northern oak woodlands in California, Oregon white oak is found 

in “scrub” form with shallow soils and rocky 

forested openings (Griffin 1977, Barnhart et al. 

1987). Succession on these “poor” quality sites 

in California, which are also often dominated by 

grasses, is much slower compared to the typical oak woodlands of the Willamette Valley 

(Griffin 1977). Barnhart et al. (1987) note that 

a few foresters in northern California question 

the ability of Douglas-fir to survive at marginal 

sites such as these meadows; during drought 

years conifer species may lose access to water 

in the shallow soils and succumb to insect attack 

or branch cankers. A few large Douglas-firs 

were observed in the center of meadows; however, a number of younger individuals in similar 

locations showed evidence of needle loss. The 

current state of these sites suggests that succession to conifer forest is possible but will occur at 

a very slow rate, if at all.

Woodland-Type Sites

Environmental conditions in woodland-type 

sites, which were less extreme and less favorable for continued oak dominance, permitted 

much more potential for change in the canopy 

composition. The age of the oaks in these 

small woodlands suggests that they represent 

species that were capable of expanding into 

these seasonally wet and drier areas, which 

where formerly more open. However, as in the 

closed-form oak stands of the Willamette 

Valley, the environmental conditions created 

by the increased oak densities have permitted 

the initiation of succession to conifer forest. The 

canopy composition typical of woodland-type 

Patch Level

Meadow-Type Sites

The influence of environmental conditions and 

competition are demonstrated by examining 

the nature of oak and conifer growth and distribution typical of meadow-type sites. Figure 

3 depicts the typical tree distribution occurring 

along hypothetical environmental gradients that 

influence plant community composition and 

physiognomy. Closer to the center of meadows, xeric, shallow soils and greater availability 

of light at ground level facilitate the persistence of oaks. Although oaks are capable of colonizing these areas, their growth is extremely 

slow. Moving towards the edge of meadows, 

slightly decreased sunlight intensity and denser 

litter layers from surrounding vegetation create more mesic conditions and likely deeper 

soils. Taller oaks typically occurring in this 

region of the meadow are probably responding to the more favorable conditions, which 

at some sites still may be too extreme for 

potentially competing conifer species. The 

edge of meadows seems to represent a current environmental threshold where nonoak 

species, primarily Douglas-fir, are able to persist. 

Oaks also occur at this edge but, due to 

decreased light availability and possibly continuing increases in conifer abundance, they 

often have smaller crowns and sparse leaf 

cover, with boles and limbs bending into the 

available light of the meadow.

These small, xeric locations may represent 

a refuge for oaks within the conifer-dominated landscape. While oaks in more mesic 

sites were often overtopped, the poor quality of these sites may permit oak growth to 
28

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Meadow-Type Site

Decreasing light at ground

Meadow

100 ft

Decreasing soil depth/water

Woodland-Type Site

100 ft

Patch

boundary

Conifers

Oaks

Legend

Figure 3. Typical spatial pattern of oaks and conifers in meadow and woodland sites. Hypothetical environmental 

gradients influencing tree distribution in meadow sites are also shown.

sites (Figure 3) depicts an oak stand dominated 

by closed-form oaks in midcanopy positions 

with scattered conifers in the upper and lower 

canopy layers, which will likely slowly succeed 

the slower growing oaks. This form of succession is also occurring in some very small areas 

outside of the xeric soils at meadow-type sites 

where conditions permit conifer growth.

Although this type of succession is more typical 

of woodland-type sites in the Willamette Valley, 

the similarity may only reflect the relatively 

recent increases in oak density and formation 

of dense oak woodlands resulting from fire 

suppression. At forested oak stands in the 

Willamette Valley, Thilenius (1968) regularly found two-aged stands with a minimum 

of one “relict” oak greater than 40 inches 

dbh per acre. This represents the xmaximum 

number of oaks per acre of this size observed 

during the surveys. The absence of relic 

trees, large snags, and stumps suggests that 

conditions at these sites may not have been 

similar to the pre-European settlement oak 

savanna Thilenius (1968) describes for the 

Willamette Valley.
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Effects of Fire Suppression

The primary causes attributed to the alteration of oak woodlands in the Willamette 

Valley and surrounding areas include suppression of fire, removal of oaks for fuel and 

urban development, and grazing practices 

that alter soil conditions (Johannessen et al. 

1971; Towle 1982). Because the surveyed 

sites were generally isolated from urban disturbances and virtually no evidence of grazing 

and cutting of oaks was found, changes in fire 

frequency have potentially had the greatest 

effect on these oak woodlands.

The frequent and very extensive burning of the 

Willamette Valley prairies by Native Americans 

documented by early explorers and settlers 

(Johannessen et al. 1971) must have reached 

well into neighboring hills and valleys (Cole 

1977). Natural fires may have also been frequent in the Western Cascades, particularly in 

drier areas (Morrison and Swanson 1990).

Thilenius (1968) has described the effects 

of postsettlement fire regime on Willamette 

Valley oak stands. He found that in the former 

oak savannas and prairies, younger forest-form 

oaks had started growing near the time when 

both natural and human induced fires began to 

be suppressed, following the large immigration 

of Euro-Americans in the 1840’s. A similar 

trend of increased densities of oaks and other 

species <150 years old would be expected in 

oak woodlands in neighboring areas where 

fires also regulated plant communities.

The mean age estimated for forest-form, cored 

trees on BLM woodland-type sites (164 years) 

suggests that the majority of these closed-crown 

stands also originated at the time of European 

settlement. Large and older open-form 

oaks, snags, and decaying logs were very rare or 

absent. Although there were only a few signs 

of oak harvesting, it is possible that the lack of 

snags and larger trees was due in part to past 

removal. In some sites, fallen snags may have 

also been very decayed and were not detected during surveys.

Wildlife Habitat 

Associations

Species That Use Oak Woodlands

Most of the available data on wildlife use of oak 

woodlands in the West comes from California. 

According to Ryan and Carey (1995a), there are 

331 terrestrial vertebrate species that use oak 

woodlands, including 120 mammals, 147 birds, 

and 60 herpetofauna; Barrett (1980) suggested 

that at least 60 mammal species use oaks; 

Block and Morrison (1998) found 19 species 

of herpetofauna; and 110 bird species were 

recorded using oak habitats by Verner (1980) 

in California. Gumtow-Farrior and GumtowFarrior (1992) listed 214 vertebrates that nest 

and forge in Oregon oak woodlands. Hagar and 

Stern (1997) observed 77 bird species using oak 

woodlands in the Willamette Valley, including 

43 residents, 29 migrants and 3 exotic species. 

Pacific Wildlife Research (1998), using similar 

study sites in Oregon, found 15 herpetofauna, 

including 2 salamanders, 1 newt, 4 frogs, 3 

lizards, and 3 snake species. Studies on oak 

woodlands in Oregon are limited because of 

their limited distribution in a state dominated 

by coniferous forests. Appendix A provides a 

list of wildlife species that are most likely to use 

oak woodlands in Lane County, Oregon.
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The following species appear to be associated 

with oak woodlands or some component of 

oak-dominated communities and have distributions in Lane County, Oregon. Most of 

these species may occur in other types of plant 

communities, but when oaks are present, they 

rely on them. There are other species that 

could be considered oak woodland-associated 

based the definition used for this assessment, 

and there would probably be many others 

if information on habitat utilization of oak 

woodlands was available.

Deer

The extent to which deer use oaks can be particularly heavy, and when acorns are available 

during the fall and winter seasons, they are the 

primary food source of the white-tailed deer 

(Odocoileus virginianus) in oak woodlands 

(Christisen and Korschgen 1955). Menke and Fry 

(1980) examined rumen contents of 61 blacktailed deer (Odocoileus hemionus columbianus) 

in California and found year-round consumption of oak browse (twigs and leaves) averaged 

21.5 percent of their diet per month. The highest seasonal consumption they found was in the 

summer when oak browse and acorns accounted 

for 60 percent of their diet. Acorns alone constituted 15-20 percent of their diet in the summer and fall (Menke and Fry 1980). Similarly, 

monthly consumption of acorns ranged from 

0 percent in June to 62.4 percent in October, 

and averaged 25.2 percent per month over a 

period of 6 years (Christisen and Korschgen 

1955). Coblentz (1980) found 48 percent of the 

stomach contents of four black-tailed deer 

were comprised of acorns in the Willamette 

Valley, Oregon. Studies throughout the United 

States have found similar results for deer 

(Pearson and Burnett 1940; Forbes et al. 1941; 

Sanders 1941; Pearson 1943; Halloran 1943; 

Taylor 1944; Dalke 1947; Dexter et al. 1952; 

Lay 1957; Collins 1961; Duvendeck 1962; Lay 

1965). Acorns are a high-energy source of food 

and have a strong influence on reproduction, 

survival, and population levels of deer in a 

given year (Nichol 1938; Forbes et al. 1941; 

Duvendeck 1962).

Sharptail Snake

In part because of its limited distribution, 

especially in Oregon, the sharptail snake 

(Contia tenuis) has been designated as “sensitive and vulnerable” (SV) by the Oregon 

Department of Fish and Wildlife (Marshall 

et al. 1996). Cook (1960) described specific 

accounts of the species in California and 

Oregon, most in close proximity to oaks. 

Applegarth (1994) suggested that sharptail 

snakes are found in open oak woodlands 

mixed with madrone and chinkapin, with 

<40 percent canopy cover and with a grass, 

forb, brush understory, often accompanied 

by poison oak. Cook (1960) suggested the 

distribution of sharptail snakes might be 

limited by their specific food preference of 

small slugs. In contrast, Applegarth (1994) 

suggested that habitat loss of oak/grass 

woodlands due to cattle grazing and conversion to Douglas-fir forests have limited the 

distribution of sharptail snake populations. 

The sharptail snake is considered rare in 

Lane County (Applegarth 1994). However, 

the BLM oak patch sites sampled are very 

similar to those considered as good sharptail 

snake habitat.
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Wild Turkey

Wild turkeys (Meleagris gallopavo) have been 

introduced in Oregon and are found in oak 

woodlands and oak-conifer habitats. Their diet 

includes seeds, nuts, grains, buds, leaves, arthropods, and some vertebrate species, but acorns 

are a preferred food in winter when they are 

available. Wild turkey acorn consumption has 

been found to continue throughout all or most 

of the year in many areas (Christisen and 

Korschgen 1955; Good and Webb 1940; May et 

al. 1939; Mosby and Handley 1943). Monthly 

percentage of total volume of acorns consumed 

ranged from 0.5 percent in September to 73.3 

percent in January and averaged 22.7 percent per 

month in Missouri (Christisen and Korschgen 

1955). Similar studies reported heavy utilization of acorns by wild turkeys (Good and 

Webb 1940; Ligon 1946; May et al. 1939; 

Mosby and Handley 1943). Uhlig and Bailey 

(1952) suggested wild turkey mortality rates 

were associated with low mast production in 

West Virginia. Smith and Browning (1967) 

found that grass seed was the primary staple 

of wild turkeys in oak woodland chaparral 

habitat in California, with acorns being only 

a secondary source in the fall. They suggested that competition for food (from cattle 

and other birds), rather than the food source 

itself, may be a potential limiting factor to 

turkeys in California.

Acorn Woodpecker

The acorn woodpecker (Melanerpes formicivorus), unlike most other oak woodland 

associates, is specifically restricted to habitats 

that have some oak component, whether they 

are oak woodlands or oak-pine forests. Acorn 

woodpeckers feed primarily on insects, small 

vertebrates, wild oaks, fruit, oak buds and 

flowers, and acorns (Koenig 1980). Koenig 

(1980) stated that stored acorns are often 

used year-round, but most importantly in 

September-March, and MacRoberts and 

MacRoberts (1976) suggested acorn woodpecker winter diets in California consisted 

almost entirely of acorns. Koenig (1978) and 

Hannon et al. (1987) suggested that populations and reproduction are limited by the 

availability of an adequate supply of stored 

acorns during the more crucial winter months. 

Similarly, Koenig and Mumme (1987) found 

that reproductive success, clutch size, population dynamics, and winter survival rates of the 

acorn woodpecker were all determined by 

the available supply of stored acorns. Koenig 

(1980) estimated that stored acorns account 

for only about 6-7 percent of the total annual 

metabolic requirements of acorn woodpeckers. 

According to Wilson et al. (1991), the dbh 

of granary trees selected by acorn woodpeckers 

was significantly larger than nongranary trees, 

and they suggested that acorn woodpecker 

populations are limited by the availability of 

large >30 inches dbh oaks. They also suggested 

acorn woodpeckers are important as the primary 

excavators for secondary cavity nesters in oak 

woodlands. Wilson et al. (1991) suggested management that maintains large oaks (>20 inches 

dbh) to benefit the entire cavity nesting guild.

Western Gray Squirrel

Western gray squirrel (Sciurus griseus) distribution in Oregon and Washington is mostly in 

conifer-hardwood forests with a strong component of Oregon white oak (Cross 1969), 

and the forests they inhabit usually have 
32

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some species of oak present (Asserson 1974; 

Cross 1969; Foster 1992; Gilman 1986). The 

squirrel is listed as “sensitive-undermined” by 

the Oregon Department of Fish and Wildlife 

(Marshall et al. 1996). Acorns and conifer seeds 

are a primary component of their summer-winter diet in California, Oregon, and Washington 

(Asserson 1974; Barnum 1975; Cross 1969; 

Foster 1992; Stienecker and Browning 1970), 

but fungi, fruits, buds, and leafy vegetation are 

also important (Byrne 1979; Foster 1992; Maser 

et al. 1978; Ryan and Carey 1995a; Stienecker 

and Browning 1970). Ryan and Carey (1995b) 

found western gray squirrels were positively 

associated with food-producing shrubs including snowberry, California hazel, bigleaf maple 

(Acer macrophyllum), vine maple (Acer circinatum), salal (Gaultheria shallon), and blackberries, and negatively associated with Scotch 

broom. The high-energy content of mast foods, 

in addition to their ability to stay fresh when 

stored for use during more critical months 

when other food availability is low, makes them 

a superior food source during some seasons of 

the year (Stienecker and Browning 1970). Ryan 

and Carey (1995a) suggested oaks may be the 

single most important source of food for western gray squirrels; however, annual mast production by oak species can be highly variable 

(Beck 1993) and acorns are an unpredictable 

source of food for wildlife. Western gray squirrels must rely on other foods, including seeds, 

buds, and stems from other trees; fungi; and 

forbs during years when the acorn crop is low 

or has failed (Ryan and Carey 1995a). Ryan and 

Carey (1995a) suggested two of the most limiting factors of western gray squirrel abundance 

are the availability of oak-dominated habitats 

and the availability of mast, and they suggested 

that management for western gray squirrels 

include a minimum of 18 ft 2 basal area of 

oaks. They predicted that the minimum size 

required for oak stands to support western 

gray squirrels was 2-3 acres for short-term 

usage and >5 acres to support long-term 

requirements.

Dusky-Footed Woodrat, Common 

Bushtit, Scrub Jay, White-Breasted 

Nuthatch, and Mourning Dove

Information on these remaining oak woodland-associated species, the dusky-footed 

woodrat (Neotoma fuscipes), common bushtit 

(Psaltriparus minimus), scrub jay (Aphelocoma 

caerulescens), white-breasted nuthatch (Sitta 

carolinensis), and mourning dove (Zenaida 

macroura), is limited to more generalized group 

studies instead of species-specific assessments of 

habitat utilization of oak woodlands. A combination of these studies and information on 

the ecology and habits of each species from 

the literature was used to categorize them as 

oak woodland associates.

Habitat Components 

of Oak Woodlands

Food

Acorns are an important high-energy food 

resource to many wildlife species in oak 

woodlands (Block et al. 1990; Pavlik et al. 

1991; Kerns 1980; Goodrum et al. 1971; 

Christisen and Korschgen 1955; Martin et 

al. 1951). Acorns are an important seasonal 

source of energy prior to the harsh winter 

months when other foods are less abundant 

or nutritious (Block et al. 1990), and are 

used year-round by some species that cache 

the surplus (Goodrum 1940; Good and 
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A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

Webb 1940). Christisen and Korschgen (1955) 

listed deer, turkeys, quail, ducks, and crows as 

species that rely heavily on acorns for food during parts of the year. Some experts suggested 

that at least 37 species of terrestrial mammals 

and 30 birds eat acorns in oak woodlands in 

California (Block et al. 1990). Acorn availability is important for the survival, reproductive success, and population size of many 

oak woodland species (Forbes et al. 1941; 

Linduska 1950; Burns et al. 1954; Uhlig 1956; 

Duvendeck 1962). Van Dersal (1940) suggested that the distribution of some wildlife species may be associated with the range of oak 

habitat, and Coblentz (1980) suggested that 

acorn loss by oak removal would have detrimental effects on local populations of some 

species in the Willamette Valley. Goodrum et 

al. (1971) suggested that freezing temperatures resulted in acorn crop failure during 1 

year of their study, and Sharp and Sprague 

(1967) found 4 years with total crop failure 

and partial crop failure in 4 other years over a 

50-year period due to freezing temperatures. 

In addition to weather, Block et al. (1990) 

listed genetics, nutrition, close proximity to 

other trees causing root crowding and shading, 

soil conditions, and physiographical features 

as variables that may affect acorn production. 

The negative impact of acorn crop failure on 

some wildlife populations can be devastating. 

For example, Christisen and Korschgen (1955) 

suggested that there was a direct correlation 

with gray squirrel abundance and the abundance of acorns, and population levels of gray 

squirrels, bears, pigs, and deer may be limited 

by the annual crop of acorn mast (Goodrum 

1940; Duvendeck 1962; Piekielek and Burton 

1975; Barrett 1978).

Oak foliage and plant species associated with 

oaks are another important food source to 

wildlife in oak woodlands. Kerns (1980) found 

wildlife species diversity and abundance was 

associated with the density of understory 

plants in northern California oak habitats. 

Block et al. (1990) suggested that the majority 

of wildlife in California oak habitats depend 

on the fruit from plants associated with oak 

woodlands. Some of the more common fruit 

bearing shrubs in California oak woodlands 

include: redberry (Rhamnus crocea), coffeeberry (R. californicus), buckbrush (Ceanothus 

cuneatus), toyon (Heteromeles arbutifolia) and 

mistletoe (Phoradendron spp.) (Block et al. 

1990; Block and Morrison 1991). Manzanita 

and mistletoe and other species of Ceanothus

may provide food resources for animals in 

Oregon oak woodlands. Kerns (1980) compared mature oak, mixed oak-conifer, young 

oak, and oak conifer edge habitats in northern 

California and found that the mature oak 

habitats with dense understory of shrubs and 

grasses were highest for species diversity and 

abundance of wildlife. Kerns suggested that the 

fruit, seeds, stems, and leaves from shrubs, 

combined with the niche created by the vertical edge between the shrub layer and the 

mature oak canopy, produce desirable habitat 

for a variety of wildlife species.

Cover

According to Ingles (1965), Barrett et al. 

(1976), and Pavlik et al. (1991), oaks provide 

an important source of cover from exposure 

for mammals in California. The combination 

of trees and shrubs in oak woodlands provides 

a vertical structure that helps conceal mammal 
34

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

den sites and prey from predators and provides 

habitat for many shrub nesting bird species 

(Pavlik et al. 1991). Leaf litter, grass and forb 

cover, and coarse woody debris are important 

cover variables to herpetofauna in California oak 

woodlands (Block and Morrison 1998). Cavities 

in standing or fallen oak trees and snags are used 

for nesting, estivation, and protection from predators by many amphibian and reptile species; in 

addition, there is a diverse community of bird 

species that nest in oak canopies and others that 

rely on cavities for nesting (Pavlik et al. 1991). 

Verner (1983) suggested that oak woodlands 

were among the top three habitat types in North 

America for breeding bird diversity. Hagar and 

Stern (1997) found more neotropical migrants 

breeding in oak woodlands in the Willamette 

Valley than others have found in Douglas-fir 

forests in western Oregon (Carey et al. 1991; 

McGarigal and McComb 1992), and many of 

the more common resident species they found 

were rare or absent from closed canopy Douglasfir forests. Wilson et al. (1991) found 6 of the 10 

most abundant breeding birds in California oak 

woodlands were cavity nesters. Cavity nesters 

comprised 25 percent of the breeding species 

and more than 58 percent of the total individuals breeding in their study, which they suggested 

is higher than densities of most other bird communities in temperate regions.

Restoration 

and Management 

Literature Review

Conifer Encroachment

Intensive efforts to restore Oregon white oak 

woodlands have been conducted at two public 

parks in Northern California: Redwood National 

Park and Annadel State Park. Literature on 

similar restoration studies in oak woodlands 

of the Pacific Northwest was not located at 

the time of this review.

Oak woodlands in Redwood National Park are 

known as bald hills oak woodlands, which are 

characterized by a patchy mosaic of oak- and 

grass-dominated areas (Reed and Sugihara 

1987). Suppression of frequent fires (both natural and those set by Native Americans) is 

believed to have led to increased oak densities 

since the 1850’s (Reed and Sugihara 1987), 

forming more even-aged stands and more narrow-crowned trees. Douglas-fir encroachment 

has noticeably decreased the extent of prairie 

and oak woodland (Sugihara and Reed 1987b). 

In order to achieve the park’s goals of managing and restoring these oak woodlands, various prescribed burns have been carried out 

(Sugihara and Reed 1987a, 1987b). When 

sufficient fuels occurred in areas to be 

burned, low-intensity backing and head fires 

killed nearly all Douglas-firs <9 feet and larger 

Douglas-firs that were very scorched (70 percent scorching of trees or greater) (Sugihara 

and Reed 1987b). These fires also top-killed 

most oaks <9 feet; however, these individuals 

sprouted back in the following years. Larger 

oaks, >9 feet, were generally unharmed and 

also produced basal sprouts following the fires. 

Less intense fires (fires remaining in the 

understory) were unable to kill trees >9 feet.

Sugihara and Reed (1987a) concluded that 

in order to successfully control Douglas-fir 

growth, fire frequency would need to occur 

at least every 10 years. They have also suggested that creating a multiaged stand of oaks, 

typical of pre-European settlement in this area, 
35

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would require low-intensity fire at intervals 

of approximately 5 years. In the bald hills of 

Redwood National Park, regular low-intensity fires would likely decrease the damage 

to canopy trees while lowering the constant 

regeneration from previous fires. In addition, 

sustained burning may restore other native 

vegetation adapted to frequent fires.

Sugihara and Reed (1987a) have also recommended combining prescribed burning with 

manual removal and/or girdling of larger invasive trees that will not be effectively controlled 

by fire. Girdled trees may also provide snags 

for wildlife species.

Studies and work conducted at Annadel State 

Park in the Sonoma Mountains of California 

have focused on describing the causes of 

Douglas-fir invasion and restoration strategies 

for oak woodlands at this park (Barnhart et 

al. 1987; Barnhart et al. 1996; Hastings et al. 

1997).

Restoration work of oak woodlands at Annadel 

State Park has included both manual removal 

of Douglas-fir and prescribed burning of portions of the park (Hastings et al. 1997). Initial 

efforts included a combination of prescribed 

burning in “high priority areas” along with 

two cutting treatments for Douglas-fir trees 

>6 inches dbh: 1) application of glyphosate to 

shallow cuts in the cambium layer of larger 

Douglas-firs, and 2) felling of smaller trees, 

which added fuel for burn areas. Trained volunteers later repeated manual removal using 

the frill cuts without herbicide treatment. 

Additional prescribed burns were conducted in 

larger areas (95-242 acres) and monitored to 

assess survival and regeneration.

Hastings et al. (1997) reported that Douglasfirs receiving the herbicide treatments were 

killed; however, recruitment of this species 

continued in areas where large trees were left 

standing and numerous smaller felled trees 

were able to sprout from stumps left too high. 

Additional cuts without herbicide were effective; however, some trees >12 inches dbh survived, likely due to shallow cuts.

Prescribed burning was effective in decreasing the number of Douglas-fir seedlings per 

acre by 50 percent, while Oregon white oak 

seedlings increased by 9 percent. Areas of 

native California fescue grasses (Festuca californica) burned with high intensity, while 

areas with less surface fuels permitted survival 

of Douglas-fir seedlings.

Because prescribed burning is not effective in 

all areas, current management strategies at this 

park include using a combination of burning 

and manual removal of seedlings where burning is not as effective (Hastings et al. 1997).

Thinning of 

Closed-Canopy Stands

McDonald and Ritchie (1994) have suggested 

that thinning of California black oak stands 

may be beneficial for wildlife by allowing trees 

to produce larger crowns, leading to increased 

acorn production. However, they point out 

that thinning of this species often results in 

the formation of epicormic branches that yield 

no acorns. These small subcrown branches are 

produced by less vigorous trees often occurring in closed canopy stands. McDonald and 

Ritchie suggest that a series of thinnings will 
36

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

allow the trees to gradually increase in vigor, 

and thus crown size, and reduce the rate of 

epicormic branching.

Tappeiner and McDonald (1980) note that for 

California black oak, although acorn production 

generally increases after 80 years, the incidence 

of heart rot also increases at this time. Therefore 

they suggest that the availability of acorns may 

be more continuous in oak woodlands if two 

broad age classes of trees (0-80 and 81-120+ 

years) are maintained. Because mast production often varies among trees at individual 

sites (Beck 1993), identifying and retaining 

better producing trees may also increase the 

availability of acorns for wildlife.
37

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SUMMARY AND RECOMMENDATIONS S U M M A R Y A N D R E C O M M E N D A T I O N S

Vegetation Patterns

The vegetation structure and spatial distribution 

of oaks is highly variable among the 13 BLM 

sites surveyed. From a landscape perspective, all 

of the sites represented small patches of oaks 

(median area = 2 acres) imbedded in a heterogeneous mosaic of conifer stands, clearcuts, 

and non-forested areas. However, some BLM 

sites (e.g., Cougar Mountain, Gilkey Creek, Sears 

Road) represented only a portion of a larger oakconifer woodland extending outside of the 

surveyed patch boundaries. The relatively 

small patches of oaks delineated do not adequately represent the structural or compositional richness of the plant communities observed 

at the BLM sites. The spatial distribution of oaks 

often appeared to be influenced by environmental gradients (i.e., soil moisture, aspect), and 

oak trees were frequently interspersed among 

conifers and other hardwood species. Oaks that 

are able to persist among conifers in canopy gaps 

or along stand edges provided a unique structural 

component in the vertical stratification of these 

stands. Arboreal lichens, other epiphytes, and 

nonvascular plants associated with oaks are likely 

to increase the plant species diversity at the BLM 

sites to a much greater extent than the presence 

of oak as a single tree species would indicate.

Much of the variation in oak distribution 

observed on the BLM sites appears to be influenced by interactions among aspect, slope 

position, and soil characteristics that influence 

microclimate and soil moisture. Oak trees 

tended to be most highly aggregated on xeric, 

south- or southwest-facing hill slopes or ridges 

that were less favorable to conifer reproduction. On the most extreme sites, even oaks 

are infrequent and the sites are dominated by 

grass or shrubs. It remains unclear whether 

oaks will eventually infiltrate these meadows 

and dominate the site; it may be that these 

areas are so prone to drought that tree establishment is unlikely to ever occur. In general, 

oak regeneration was not abundant and most 

commonly observed in areas where light levels 

were relatively high; i.e., meadows and light 

gaps in woodland-type patches. Most of this 

regeneration was vegetative sprouting, which 

formed the clusters of shrub-form oaks characteristic of meadow-type patches. Live oak trees 

rarely were observed to have crowns in dominant canopy positions on mesic sites, although 

decadent oaks interspersed among conifers or 

big-leaf maples occurred at a few sites.

These observations may indicate that most of 

the BLM sites situated on xeric, mid- to upperslope positions are likely to have oak trees in 

dominant or codominant canopy positions, 

regardless of fire suppression (assuming no 

tree harvest). However, there is evidence (e.g., 

oak snags under conifer canopies, Douglas-fir 

seedlings/saplings under oaks) that Douglasfir are becoming more abundant on mesic 

sites and dominating stands that had been 

oak-conifer woodlands and savannas. Based 
38

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

on these observations at the BLM sites and 

a review of vegetation studies conducted 

in the Willamette Valley and foothills of the 

Cascades, it appears that the cessation of perennial fires by Native Americans and active fire 

suppression has promoted conifer succession on 

all but the driest sites.

Vegetation maps of Lane County constructed 

from surveys performed in the 1850’s indicate 

that the BLM McKenzie and South Valley 

Resource Areas were a heterogeneous landscape of Douglas-fir forest, mixed coniferhardwood forest, Oregon white oak-ponderosa 

pine forest, mixed species savanna, and prairie. 

Most of the BLM sites surveyed appear to 

have been closed-canopy forest or woodland 

plant communities at the time of European 

settlement in this area (Table 13). However, 

notes from the historic surveys suggest that 

tree densities were lower and average tree 

diameter in these stands may have been 

greater than the 1998 estimates. Retrospective 

studies (Johannessen et al. 1971; Cole 1977) 

and the 1850’s surveys also indicate that ponderosa pine was commonly associated with 

oaks in this area and probably much more 

extensively distributed in the Willamette 

Valley foothills than it is today.

Some federal planners and ecologists have 

recommended that natural forests serve as a 

reference to guide desired composition and 

structure of forest reserves (Dombeck 1996; 

Thomas 1996; Swanson et al. 1997). If oak 

woodlands such as those surveyed are to be 

managed in this way:

❖ The diversity of tree species should be 

sustained: although there is no data 

available to fully examine the variation 

of forest composition prior to European 

settlement, the 1850’s surveys suggest 

that much of the McKenzie and South 

Valley Resource Areas were mixed 

stands of Douglas-fir, ponderosa pine, 

and Oregon white oak.

❖ The importance of meadows, canopy 

gaps, and rocky balds should be recognized: these relatively small openings 

are relatively undisturbed (compared 

to adjacent pastures and clearcuts) and 

may be important strongholds for native, 

early seral plants, reptiles, and small 

mammals.

To help determine possible management or 

restoration actions, the 13 surveyed sites were 

classified into three groups based on site characteristics and the degree of oak-conifer competition observed (Table 14):

❖ Xeric: Dry sites on ridges or steep, 

south-to-southwest hill slopes have limited oak size and conifer growth in these 

sites, which have likely undergone the 

least amount of change in community 

structure post-European settlement.

❖ Mesic: Lower slopes and increased patch 

cover by more mesic soils in these sites 

have provided more favorable growing 

conditions and thus greater and more 

rapid changes in canopy composition 

over time relative to xeric sites.

❖ Wet: Sites occurring on low slopes 

where mesic and seasonally wet soils 

covered >50 percent of the patch area 
39

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Table 13. Historical vegetation classifications for the surveyed sites. Classifications are taken from GIS 

maps created from interpretative data of Christy et al. (1996, 1997). A dashed line in the table indicates 

that information was not available for that location.

have undergone the most dramatic 

changes in canopy composition. Within 

the last 150 years, closed-canopy oak 

and mixed conifer stands have developed to 

cover the majority of these formerly more 

open areas.

	 Site	 Major Vegetation Classification	 Specific Vegetation Classification

Anthony Creek Closed forest upland -

Bates Woodland Scattering or thinly timbered Douglas-fir/white oak 

 (bigleaf maple) woodland, with brushy undergrowth of 

 hazel, other shrubs, oak brush, oak stump sprouts,young 

 Douglas-fir, bracken, briars, and sometimes willow. 

Cougar Mountain Prairie, closed forest upland -

Eagle's Nest - -

Fox Hollow - Mixture of 1) xeric Douglas-fir/Chinquapin-madrone 

 forest on south slopes 2) mesic Douglas-fir/bigleaf 

 maple forest on north slopes and bottoms, sometimes 

 with incense cedar, oak, grand fir, red cedar, yew, red alder 

 and dogwood.

Gilkey Creek Closed forest upland bordering Bordering areas: Oregon white oak/Douglas-fir/ponderosa pine 

 savanna and prairie savanna and white oak/ponderosa pine savanna.

Kloster Mountain - -

Rattlesnake Butte Woodland and closed forest upland -

Sears Road Prairie -

Seventy-Ninth Closed forest upland -

Weiss Road Woodland Scattering or thinly timbered Douglas-fir/white oak (bigleaf 

 maple) woodland, with brushy undergrowth of hazel, other 

 shrubs, oak brush, oak stump sprouts, young Douglas-fir, bracken, 

 briars, and sometimes willow.

Wendling - Mixture of 1) xeric Douglas-fir/Chinquapin-madrone forest on 

 south slopes 2) mesic Douglas-fir/bigleaf maple forest on north 

 slopes and bottoms, sometimes with incense cedar, oak, grand fir, 

 red cedar, yew, red alder and dogwood.

Wills Road Woodland and -

 closed forest upland -
Xeric

Anthony Creek (M)

Bates (could also be in mesic group) (M)

Kloster Mountain (M)

Mesic

Fox Hollow (W) (could also be in 

 wet group)

Gilkey Creek (M)

Rattlesnake (M)

Seventy-Ninth (M)

Wendling (M)

Weiss Road (M

Wet

Cougar Mountain (W)

Eagle’s Rest (W)

Sears Road (W)

Wills Road (W)

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Table 14. Classification of surveyed sites based on site characteristics, degree of conifer competition, and 

possible management actions.

- protect meadows by controlling increase of nonnative plant cover

- monitor and eliminate future conifer 

encroachment

- sustain and/or restore diversity of 

tree species, particularly ponderosa pine 

and Oregon white oak

- control nonnative plants

- historic vegetation classifications 

may provide reference conditions

- possible silvicultural methods include 

thinning of conifers and smaller oaks; 

snag creation

- restoration of open woodlands, prairie, 

savanna will require intensive, susained 

efforts

- eliminate/control abundant nonnative 

plants 

- silvicultural treatments may include 

selective thinning of oaks and conifers; 

prescribed burning; snag creation

- dry, steep slopes

- low soil moisture levels

- oaks typically shrubby and short (< 40 feet) 

with thin stems

- medium slopes

- low to medium soil moisture levels

- open areas with small shrubby or stunted 

oaks

- woodland areas with larger oaks (30-60 

feet) typically overtopped by conifers to 

some degree

- low slope areas

- medium to high seasonal soil moisture levels

- large (60-80 feet) forest form oaks; only a 

few older open grown trees with conifer 

encroachment very evident

	 Site Groupings	 Environmental Conditions and Oak 	 Possible Ecosystem Management

Growth and Distribution Characteristics	 or Restoration Actions	

	 (M =meadow community type;

	 W =woodland community type)
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Wildlife Habitat

Mast Production

Goodrum et al. (1971) studied the relationship between acorn production and tree characteristics of seven oak species in Texas and 

Louisiana. He found acorn yields generally 

increased with age, bole diameter, and crown 

size of the tree. Similarly, Christisen and 

Korschgen (1955) found a strong association 

between crown size and acorn production. 

In contrast, Cypert (1951) suggested radial 

growth rate rather than tree size was the most 

important factor determining the size of the 

acorn crop. The BLM oak patches were not 

directly samples for acorn production because 

of time and logistic constraints; however, 

expected acorn yields for white oak (Q. alba) 

from Goodrum et al. (1971) were used to calculate acorn potential production rates using 

tree dimensions from the BLM oak patches. 

Potential acorn yield based on numbers of oak 

trees in acorn producing size classes from each 

of the BLM patches ranged from 0 to 1,333 total 

pounds per oak patch (mean = 195 pounds), 

and from 0 to 494 pounds of acorns per acre 

(mean = 89 pounds) (Table 15). Sixteen of 

25 oak patch sites were predicted to yield 

less than 50 pounds/acre of acorns, including 10 that were predicted to have less than 

10 pounds/acre. The four highest yields were 

>250 pounds/acre. The reason the estimated 

yields were lower than might be expected given 

the number of trees in some of the oak patches 

is that most of the oaks were <15 inches 

dbh, which is at the smaller end of the size 

found to produce acorns by Goodrum et al. 

(1971). Although these expected yields are 

very crude estimates based on a different oak 

species from a different part of the country, 

the estimates may be high rather than low 

because they don’t account for the percentage of trees that don’t produce acorns and 

the cyclic nature of mast production. In the 

Willamette Valley, mast years have occurred 

very infrequently in the last 15 years (David 

Hibbs personal communication). Goodrum et 

al. (1971) also suggested that tree size positively influenced the percentage of trees that 

produced acorns, and an important limiting 

factor of acorn production can be freezing 

winter temperatures. Verner (1980) suggested 

managing oak woodlands for wildlife should 

include a minimum of 100 pounds of acorns 

per acre, which exceeds the approximated 

acorn yield for 70 percent of the oak patches 

sampled. Therefore it appears that only the 

Cougar Mountain, Eagle’s Rest, Gilkey 

Creek, Sears Road, and Wills Road sites might 

be capable of producing a significant abundance of acorns available for wildlife.

Vegetation

Average shrub coverage ranged from 24 to 65 

percent in nine oak woodland sites in the 

Willamette Valley (Hagar and Stern 1997). 

Poison oak was the dominant shrub species in 

four of their sites, and Franklin and Dyrness 

(1988) stated it to be the dominant shrub 

species in most oak woodlands in Oregon and 

Washington. Similarly, poison oak dominated 

the understory vegetation in the oak patches 

sampled. In addition, there was a high frequency 

of nonnative plant occurrence (Table 10). 

However, in contrast to Hagar and Stern (1997), 

coverage of other shrub species important to 
42

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Table 15. Estimated annual acorn yields for the surveyed patches. Yields were approximated using data from 

Goodrum et al. (1971; Table 2) and estimated numbers of oak trees in acorn-producing size classes.

Total Estimated	 Estimated	

Patch Area	 Acorn Yield	 Acorn Yield	

	 Patch	 (acres)	 (pounds)	 (pounds/acre)	

ANTH-1 1 5.0 5.0

ANTH-2 2 5.0 2.5

ANTH-3 2 5.0 2.5

BATES 3 15.0 5.0

COUG-1 2 550.0 275.0

COUG-2 2 290.0 145.0

EAGL-1 1 495.0 495.0

EAGL-2 2 790.0 395.0

FOX 2 110.0 55.0

GILK-1 2 275.0 135.0

GILK-2 1 35.0 35.0

GILK-3 2 165.0 80.0

KLOS-1 3 5.0 2.5

KLOS-2 3 5.0 2.5

KLOS-3 5 0.0 0.0

KLOS-4 3 15.0 5.0

RATT-1 4 100.0 25.0

RATT-2 3 60.0 20.0

RATT-3 4 90.0 20.0

SEARS 5 1,330.0 265.0

SEVENT 2 35.0 15.0

WEISS 3 150.0 50.0

WEND-1 2 15.0 7.5

WEND-2 3 0.0 0.0

WILLS 2 330.0 165.0

 

Mean 195.0 88.3
43

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wildlife is much less frequent in the BLM 

oak patches, and many that were common in 

their study are rare or absent, including; service 

berry (Amelanchier alnifolia), ootka rose (Rosa 

nutkana), and snowberry. Thilenius suggested 

that previously grazed areas favor poison oak 

growth because cattle often avoided it, giving it 

a competitive advantage over other more palatable shrub species, and according to Longhurst 

et al. (1979), browsing by livestock and deer 

may be the primary factor impacting regeneration of oaks in California rangelands. Mellanby 

(1968), Griffin (1971), and Block et al. (1990) 

suggested that extensive forging on shrubs 

and oak seedlings can kill or prevent some plants 

from regenerating. Grazing by wildlife, welldrained soils, shading from bordering conifer 

forests, and small patch sizes, probably all contribute to the invasion of nonnative plants and 

high densities of poison oak.

Cavities

The importance of cavities to wildlife in oak 

woodlands was discussed earlier. Hagar and 

Stern (1997) suggested that large-diameter white 

oak trees grown in open areas in Oregon usually produce a greater number of cavities than 

the same diameter class would in Douglas-fir 

forests, and they found three cavity nesters in 

their study were positively correlated with 

tree diameter. Similarly, five cavity nesters 

and one open nester were positively associated with the abundance of large-diameter trees 

(>20 inches dbh) and the abundance of cavities (Wilson et al. 1991). There were only 4 

total oak snags >20 inches dbh and 27 conifer 

snags found among all 13 BLM study sites. In 

addition, there were less than 10 live oaks >20 

inches dbh found at the sites. All the live large 

trees and snags >20 inches dbh located were on 

only 40 percent of the sites. Consequently, the 

value of the majority of the oak patch sites to 

cavity nesting species, especially those associated with larger diameter trees and snags, is poor. 

Hagar and Stern (1997) suggested that the 

most limiting factor in the semiopen oak 

woodlands might be large-diameter oaks for 

cavity nesting species. Although there were 

more snags in the smaller size classes found, 

again the majority of these were concentrated in 

a few sites. Over 50 percent of all the snags were 

found on four sites, and over 96 percent were 

found on just 48 percent of the sites. There were 

no oak snags found in 68 percent of the oak 

patch sites. Based on availability of large- and 

medium-sized snags, it appears that seven of 

the oak patch sites should provide ample 

opportunities for cavity nesting species.

Patch Size

Probably the most limiting factor of the oak 

patch sites, in terms of quality of oak woodland 

habitat, is their size. Wilson et al. (1991) suggested 50-100 hectares (= ~123-247 acres) as 

the minimum size of management areas for oak 

woodlands. These sites would not need to be that 

large to support populations of some oak woodland associated species; however, they would 

need to be substantially larger than these patches 

are. Sisk et al. (1997) reported that composition 

of avian communities in small oak woodland 

patches (<3 hectares) in California were primarily driven by the assemblage of birds in the 

surrounding matrix rather than intrinsic habitat 

characteristics of the oak patches. An Effective 

Area Model (EAM) proposed by Sisk et al. 

(1997) predicts that the influence of matrix on 

avian community diversity decreases as the ratio 
44

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

of patch interior to perimeter length decreases. 

Although these data are from oak (species 

unknown) woodlands in southern California, 

the results suggest that the BLM sites may be 

too small to support bird communities that 

are significantly different than the surrounding 

conifer forest.

Oak Management 

Recommendations 

by Other Authors 

Applegarth (1994) included specific recommendations for ecosystem management in 

areas where the sharptail snake is found: “A) 

Discourage Douglas-fir trees from replacing 

the grass/oak community; in the case of a 

timber sale, leave a ‘no-replant’ buffer of at 

least one tree height (50 meters) on all sides of 

the identified habitat. B) Seems best not to 

burn identified habitat and probably best not 

to burn the ‘no-replant’ buffer. C) Do not compact the soil; do not permit grazing of livestock 

within forested habitat; do not drive, build 

roads, or locate skid trails through identified 

habitat. D) Do not flood or poison habitat.”

According to Barrett (1980), wildlife biologists 

recommend the following for management of 

oak dependent wildlife: “1) maintain a 25 to 50 

percent canopy cover of oaks, 2) maintain a basal 

area of 200 to 2000 ft2 per each 40 acres, 

3) maintain a mixture of age classes including 

older, more prolific seeders, and 4) disperse 

oaks in 0.5-5.0-acre aggregations.”

Hagar and Stern (1997) conclude, “Conservation 

strategies for oak woodlands and their associated 

assemblages of neotropical-migrant and resident 

bird species should include the maintenance 

of large tracts of woodland with minimal 

edge influence. In addition, a diversity of stand 

structures will support a diversity of bird species, but species using large-diameter oaks in 

semi-open woodlands are perhaps the most 

limited, and should therefore should receive 

priority consideration in conservation planning.”

Verner (1980) recommends the following for 

birds: “Maintain mixed-species, uneven-aged 

stands, especially allowing for live oak retention; Provide a continuing supply of oaks, 

generally distributed on every 1- or 2-acre 

parcel of the management unit that presently 

supports oaks; Provide a continuing supply of 

large, old trees, especially those with a good 

record of high acorn production; Manage for a 

mean annual acorn production of at least 100 

pounds per acre; Provide an ample shrub layer 

where one occurs in existing oak stands, and 

consider the possibility of establishing shrubs 

in stands from which they were removed in 

the past; Consider needs of oak-using species 

from different, adjacent habitat types.”

Ryan and Carey (1995a) recommend that 

management guidelines for oak woodlands 

in Puget Trough should include the following: “To maximize wildlife use, maintain or 

develop corridors to link habitat fragments 

and minimize the adverse impacts of fragmenting the landscape; Retain adjacent stands 

of conifers and hardwoods; Maintain canopy 

cover of 40 to 60 percent; Maintain tree species composition at 25-75 percent oak, 25-75 

percent Douglas-fir, and 10-20 percent other 

hardwoods; Preserve a near mix of snags, dead 

and downed trees, seed trees and den trees; 

Kill overtopping Douglas-fir to allow oaks to 

grow to an open form (girdle the Douglas-firs 
45

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

for snag management or fall them to provide 

coarse woody debris); Thin oak or Douglasfir/oak stands to reduce over crowding and 

water stress and allow remaining oaks to 

become larger, more vigorous, more productive, 

and more fire resistant; Remove smaller Douglasfir trees under the oak canopy that are competing with oaks for water and that will eventually 

overtop the oaks; Retain old-growth Douglas 

fir within oak stands; Maintain a mix of age and 

size classes of hardwoods to provide sustained 

mast production, vertical diversity, and recruitment (Bleier et al. 1993); Plan periodic burns 

of the grass and shrub layer to stimulate young 

shoot growth, prevent dense shrub competition 

(particularly Scotch broom), and maintain tree 

spacing (Columbia Gorge Audubon Society 

1990).; Maintain an open to patchy understory with a high level of vegetation diversity; 

Minimize human disturbance such as excessive 

trails and roads which accelerate root damage to 

oaks and invasion of weedy species.”

47

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

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APPENDIX A P P E N D I X A A
 clouded salamander 1 2 1 

ensatina 1 1 1 

western redback salamander 2 2 

northern alligator lizard 1 1 2 2

southern alligator lizard 1 1 2 2 

western fence lizard 1 2 1 2

western skink 1 1 1

rubber boa 1 1

racer 1 1 1 1

sharptail snake 1 1 1 2

ringneck snake 2 1 1 

gopher snake 1 1 2 

western terrestrial garter snake 2 1 1 2 Dry hillside/ grass forb Deciduois- hardwood Conifer- hardwood forest Shrub-forest edge Grass-forest edge

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

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Brown

List of Wildlife Species 

Found in the 

Species
x

x

x/pine 

Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

61

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

1985 1

Potentially Occurring in the Habitats

Surveyed Sites Grass-forb hills Deciduous- hardwoods

ConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

62

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

northwestern garter snake 2 2 2 2 1

common garter snake 1 1 

western rattlesnake 1 2 2 

turkey vulture 2 2 2 

black-shouldered kite 2 1

sharp-shinned hawk 1 

Cooper’s hawk 1 1 

northern goshawk 2 

red-tailed hawk 1 1 2 2 

American kestrel 1 2 1 1 

ring-neck pheasant 2 2 2 2

blue grouse 2 2 1 1

ruffed grouse 1 1 1 1 

wild turkey 1 2 2 

California quail 1 1 2 

mountain quail 2 1 2 2 2
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

63

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x x x 

x x 

x x x 

x x x 

x x 45

x x 17 20

48

x 

x 
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

64

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

band-tailed pigeon 1 1 1 1 

mourning dove 1 1 2 1 

common barn owl 2 2 1 1 

western screech owl 1 2 1 1 

great horn owl 1 1 1 1 

northern pygmy owl 2 1 1 1 

barred owl 2 1 

northern saw-whet owl 2 2 1 1 

common nighthawk 1 1 1 1 1

common poorwill 1 1 2 2 

Vaux’s swift 2 2 1 1 

Anna’s hummingbird 1 1 2

rufous hummingbird 1 1 1 1 

acorn woodpecker 1 2 2 1 

red-breasted sapsucker 2 2 2 2 

northern flicker 1 1 2 1 
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

65

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x 46

x 37

x x 25 20 x 

x x 17 20 x 

x x x 25 30

x x 17 30

x 25 30

x x 17 20

x 

x x 25 40

38

x x 17 30 x 50

x x 15 20 33

x x 17 10 34
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

66

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

downy woodpecker 1 2 

hairy woodpecker 2 

olive-sided flycatcher 1 2 2 

western wood pewee 1 1 1 

willow flycatcher 2 1 

Hammond’s flycatcher 2 1 1

western kingbird 2 2 1 

horned lark 1 

purple martin 2 2 1 1 

tree swallow 2 2 

violet-green swallow 1 2 

Stellar’s jay 2 1 2 2 

scrub jay 1 2 1 2 

American crow 1 2 2 2 

common raven 1 1 2 2

black-capped chickadee 1 1 1 
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

67

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x x 11 10 28

x 15 20 41

x x 

x 2

49

x x 

15 10

x x 15 20 36

x x 15 20

31

x 23

44

x x 9 10 4
chestnut-backed chickadee 2 1 

bushtit 1 2 1 

red-breasted nuthatch 1 

white-breasted nuthatch 1 1 

brown creeper 2 1 

Bewick’s wren 1 2 1 

house wren 1 1 

winter wren 1 1 

golden-crowned kinglet 2 

western bluebird 1 1 1 1 

Townsend’s solitaire 1 1 2

Swainson’s thrush 2 2 1 2 

hermit thrush 1 1 2

American robin 1 1 1 1 

varied thrush 1 1 2

wrentit 1 1 

Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

68

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T
x x 9 10 43

39

x x 17 20 24

x x 17 20 x 17

x x 15 20 13

x 15

x 15 10 x 6

x 30

x 15 10 x 

7

x 5

x Grass-forb hills Deciduous- hardwoods Coniferous hardwoods Suggested dbh (inches) Minimum tree height (feet Oak Top 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

69

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

70

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

cedar waxwing 2 2 

European starling 1 2 1 1 

solitary vireo 1 1 

Hutton’s vireo 1 2 1 

warbling vireo 1 2 1 

orange-crowned warbler 1 1 1 

Nashville warbler 1 1 1 

yellow-rumped warbler 1 1 2

black-throated gray warbler 1 1 1 

MacGillivray’s warbler 2 1 

Wilson’s warbler 1 1 

yellow-breasted chat 2 2 

western tananger 2 1 1 2 

black-headed grosbeak 1 1 1 1 

lazuli bunting 1 2 

rufous-sided towhee 1 1 1 
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

71

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

19

15 10 12

20

x 35

x 42

x 3

x 

40

27

x (?) 16

x 

x 29
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

72

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

brown towhee 1 

chipping sparrow 1 1 1 1

vesper sparrow 1 1 

lark sparrow 1 1 2 

savannah sparrow 2 2 

fox sparrow 1 1 1 2

song sparrow 1 1 2 2 

white-crowned sparrow 1 2 2 2 

dark-eyed junco 2 1 1 1 

western meadowlark 1 2 

Brewer’s blackbird 1 1 1 

brown-headed cowbird 1 1 1 1 

northern oriole 1 1 1 

purple finch 1 1 1 1 

house finch 1 2 1 1 

pine siskin 2 2 1 1
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

73

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

21

25

8

11

x 26

10

x x 15 10
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

74

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

lesser goldfinch 1 2 1 

American goldfinch 1 2 1 

evening grosbeak 2 

Virginia opossum 1 2 

vagrant shrew 2 2 1 1

Trowbridge’s shrew 2 

shrew-mole 1 

coast mole 1 2 2

Townsend’s mole 2 2 1

big brown bat 2 2 

silver-haired bat 2 

hoary bat 2 

California myotis 2 

long-eared myotis 2 

little brown myotis 2 2 

fringed myotis 2 2 
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

75

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x 

14

47

x x 25 10

x x 17 20

x x 17 20

x 17 10

x x 17 10

x x 17 10

x x 17 10
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

76

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

long-legged myotis 1 1 

Yuma myotis 2 1 

pallid bat 

coyote 1 1 1 2 1

gray fox 1 1 

red fox 1 1 1 1 

black bear 2 2 

raccoon 2 1 1 

striped skunk 1 2 2 2

long-tailed weasel 1 2 2 2 2 

ermine 2 1 

mink 2 2 2 

spotted skunk 1 1 2 2 

mountain lion 2 2 

bobcat 2 2 2 2 

elk 1 1 1 1
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

77

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x x 17 10 x 

x x 17 10 x 

x 17 20 x 

x x 29 10 x 

29 10

x x x 25 10

x x x 17 10

x x 15 10

x x 25 10

x x 29 10
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

78

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

mule deer 1 1 1 1

mountain beaver 2 1 1

western gray squirrel 1 1 1 2 

California ground squirrel 1 2 2 2 

Townsend’s chipmunk 1 2 2 2

Douglas’ squirrel 2 2 2 

Botta’s pocket gopher 1 

Camas pocket gopher 1 2 2 1

western pocket gopher 1 2 2 1

bushy-tailed woodrat 2 2 2 

dusky-footed woodrat 1 1 2 

deer mouse 2 1 1 1 2 

western harvest mouse 1 

white-footed vole 2 

California vole 1 1 

gray-tailed vole 2 2
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

79

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

x x 17 20 x 

x 

x 17 20

x x 17 10

x x x 15 10
Species

Dry hillside/grass forbDeciduoishardwoodConiferhardwood forestShrub-forestedgeGrass-forestedge

Brown

Habitats

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was 

scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only 

used old-growth, no score was given.

80

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T

long-tailed vole 2 2 2

creeping vole 1 1 1

Townsend’s vole 2 2 2

Pacific jumping mouse 1 1 

porcupine 1 

black-tailed jack rabbit 1 1 2

European rabbit 2 2 2

brush rabbit 1 1 2 2

eastern cottontail 1 2 2
Grass-forb hills

DeciduoushardwoodsConiferoushardwoodsSuggested dbh(inches)Minimum treeheight (feetOakTop 50 birds

1985 1 Csuti

et al.

1995 2

Hagar

and 

Stern

1977 Snags Cavities 3

2 Species use of oak habitat

3The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 

1994-1996. Numbers refer to ranking in abundance (1-50).

81

A S S E S S M E N T O F OA K WO O D L A N D R E S O U R C E S I N B L M ’ S E U G E N E D I S T R I C T