**Hearing of Subcommittee on Public Lands and Forests of the Senate
Committee on Energy and Natural Resources (3\\13\\08)**

John Tappeiner, Professor Emeritus, College of Forestry, Oregon State
University

PhD Forestry UC Berkeley 1966,

Assistant/Associate Professor College of Forestry, University of
Minnesota 1968-1973

Regional Silviculturist California Region 5 US Forest Service 1973-1980

Associate Professor/Professor College of Forestry Oregon State
University 1980-2006

Part time Research Forester BLM, USGS 1995-1999

Taught graduate and undergraduate courses in Forest Ecology and
Silviculture, research on reforestation, shrub ecology, and thinning and
stand development of old-growth forests.

Participated in the Spotted Owl Recovery Team, the Northwest Forest Plan
, and the Sierra Nevada Ecosystem Project.

These remarks represent my views and not those of Oregon State
University.

**Managing Forests on Public Lands to Maintain and Achieve Old-growth
Forest Characteristics**

1\. Old Growth forests (OG) are an important part of western forests.
They provide habitat for a wide range of organisms. They have spiritual,
aesthetic, and historical value; they contain valuable commercial wood.

2\. Each of us has our own image of an OG forest\-\--usually large,
majestic trees in undisturbed forests. Typically OG has few very large
overstory trees, multiple layers of intermediate size and smaller trees,
herbs and shrubs in the understory and large standing and fallen dead
trees (7,9). It is this varied structure that makes OG unique. These
characteristics vary widely even within a stand, and especially
throughout the forests of Washington, Oregon, and northern California
from moist coastal forests east to the Cascades, to the drier ponderosa
pine and lodgepole pine forests east of the Cascades and the mixed
conifer of southwestern Oregon and northern California. OG may be
fragmented and occur in small patches (\<5-10 acres) with few trees. The
effects of land ownership, fire, logging, windstorms, etc. cause
fragmentation. Stands that are classified as young stands may contain
some OG trees.

3\. Fire and other disturbances like wind and insects have had and
continue to have major effects on the OG forests in the Pacific
Northwest---especially on drier sites in mixed conifer, ponderosa pine
and lodgepole pine forests (1, 8). Before about 1900 relatively
frequent, low severity fire in the ponderosa pine and mixed conifer
forests reduced fuel levels by burning small trees and shrubs, and these
fires killed few large trees. Since the beginning of fire control in the
early 1900's, fuels have accumulated in OG forests especially on dry
sites. Consequently today's fires are much more severe, killing trees
over 1000's of acres. Insects can kill young and OG trees in dense
stands during drought periods in ponderosa pine and mixed conifer
forests and especially in lodgepole pine forests. These dead trees
increase the fuels and potential for severe fire. On moist sites fire is
much less common, but when forests become dry enough to burn, fire may
kill many acres of trees. In many landscapes it is likely that fire will
start in young forests and burn into adjoining OG, so effects of fire on
today's OG also need to be viewed from a landscape perspective.

4\. There are four different goals for thinning which need to be
considered. They vary with the ecosystem in which the forest occurs: (a)
perpetuating old forest conditions threatened by severe fire from high
density of fuels, (b) bringing forest conditions to higher resilience to
drought and insects, (c) accelerating development of structural
complexity and old-growth characteristics in young forests, and (d)
growing trees for wood. (A) and (b) apply to dry forests, (c) mainly to
young moist forests. The goals can overlap, for example: (a) and (b) on
dry sites, (c) and (d) in productive moist forests, also in some dry
forest stands. In both moist and dry forests, reduction in stand density
favors rapid growth of large trees with full crowns and large branches
and furrowed bark (OG tree characteristics) (11). We found that in
western (6,10) and southwestern (8) Oregon, large, old trees grew
rapidly when they were young. Tree size (diameter) at 200+ yr was
strongly related to growth rate when trees were young (50 yr) (6). In
addition OG trees grew much more rapidly than the fastest growing trees
in nearby plantations, because of the high density of the plantation. In
addition to growing large trees, commercial thinning also initiated the
beginning of a multi-layer of trees, the establishment or maintenance of
shrubs and a yield of wood (2,3). In young stands, even before they
develop OG characteristics, the establishment of shrubs and growing
trees with large crowns provides habitat for a variety of birds (5).

Thinning stands on dry, fire-prone sites also produces the
characteristics described above. In addition, it can make a stand more
resistant to severe fire (11). This is done by (a) spacing overstory
trees when needed to reduce the density of the forest canopy and thus
the potential of a crown fire that burns from one tree to the next, (b)
growing larger trees with thick bark that are more fire resistant than
smaller trees and dense stands and (c) lowering the density of small
trees and shrubs in the understory which reduces "fuel ladders" that can
carry fire into the crowns of the large, overstory OG trees. The fire
scorches and kills the needles and vegetative buds, causing mortality.
These treatments may yield commercial wood.

5\. Removal of trees by commercial thinning, prescribed fire, and
cutting small trees by hand and tractors with cutting devices, etc. are
all ways of thinning stands to grow large trees and to reduce fuels and
flammability (11). When the goal is to reduce flammability, often no one
treatment will suffice. Slash disposal by treatments like broadcast
burning, piling and burning or chipping must follow thinning. If the
slash (dead tree tops, shrubs, etc) is not treated on fire prone sites
the potential for severe fire may be higher than before thinning, at
least temporarily. On fire prone sites treatment may be needed (about
every 15 to 20+ yr) to control ladder fuels as new trees and shrubs
become established.

On many sites it is difficult to use fire, because (a) smoke conflicts
with air quality standards, and (b) the short periods between conditions
that are too wet to burn in the winter and too dry to burn safely in the
summer. In ponderosa and lodgepole pine forests insects may breed in the
slash and emerge to attack nearby green trees. Prompt slash disposal and
timing of thinning so that the slash dries rapidly can avoid this
problem. On moist sites, slash disposal is not usually needed because it
decomposes more rapidly than on dry sites and fire is less of a concern.

6\. Thinning for fire resistance or to promote development of OG trees,
need not result in a uniform and homogeneous stand. The main purposes of
thinning are a marked reduction in ladder fuels, decrease in canopy
density and space to grow large trees. Species, sizes and spacing of
overstory and understory trees will vary to achieve desired results.

7\. OG trees respond positively to tree removal. Surprisingly stem area
growth of over 68% of large (40+ in. diameter) Douglas-fir, ponderosa
and sugar pine increased by over 10% for 20+ yr after trees were removed
from around them. About 30% of the trees increased their growth by more
than 50% and 1.5% decreased growth. Increased growth rates suggest
improved vigor that may make trees more resistant to insects and
pathogens during periods of drought. It also suggests that when thinning
young stands to provide OG characteristics, thinning can continue well
beyond 100yr.

8\. Local descriptions of OG trees and stands are needed to aid
conservation and management of OG stands. As mentioned above, the
species composition and tree sizes in the overstory and understory of OG
stands vary throughout Pacific Northwest OG forests. Forest managers,
the public and scientists need guidelines to help agree on what is OG.
These guideline are needed to set goals for managing young stands to
achieve OG characteristics. Guidelines will vary with species
composition, site productivity, and other factors such as the potential
for fire, severe insect outbreaks and windstorms. In stands that are
managed to reduce fuels and flammability, the sizes and numbers of trees
will differ from those where fire is not a concern.

Age is not likely to provide a useful description of OG. It is difficult
to determine the ages of OG trees (especially large trees). Large trees
growing on productive sites with few trees around them can be quite
young. Small trees growing on poor sites and in dense stands can be
quite old. OG stands often contain large trees with a wide range of
ages. Thus the average tree age does not adequately describe the stand.
Localized definitions of stand structure (numbers of trees of different
species and sizes per unit of land) are likely to provide the most
useful guidelines.

It is important to consider spatial variability within OG stands. Over
how large an area should OG characteristics occur? Within a 50 to 100
acre stand some acres may have 10 OG trees, others 30+ and still others
0. What is sufficient? In fire prone forests are OG characteristics or
fire proof stands needed on every acre? What is the tradeoff (if any)
between fire resistant stands and ideal OG?

Guidelines should ensure a genuine understanding and description of
local OG trees and stands, including spatial variability. They should be
local and practical to enable forest managers to implement treatments to
protect and develop OG trees and forests.

**References**

1.  Agee, J.K. 1993. Fire Ecology of Pacific Northwest Forests. Island
    Press, Washington DC.

2.  Bailey, J. D., and J. C. Tappeiner. 1998. Effects of thinning on
    structural development in 40- to 100-year-old Douglas-fir stands in
    western Oregon. *Forest Ecology and Management* 108: 99-113.

3.  Bailey, J. D., C. Marysohn, P. Doescher, E. St. Pierre, and J. C.
    Tappeiner. 1998. Understory species in old and young forests in
    western Oregon. *Forest Ecology and Management* 112:289-302.

## Latham, P., and J. C. Tappeiner. 2002. Response of old-growth conifers to reduction in stand density in western Oregon forests. *Tree Physiology* 22:137-146. {#latham-p.-and-j.-c.-tappeiner.-2002.-response-of-old-growth-conifers-to-reduction-in-stand-density-in-western-oregon-forests.-tree-physiology-22137-146. .AdvGuide-2}

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4.  Muir, P. S., R. L. Mattingly, J. C. Tappeiner II, J. D.
    Bailey, W. E. Elliot, J. C. Hagar, J. C. Miller, E. B. Peterson,
    and E. E. Starkey. 2002. Managing for biodiversity in young
    Douglas-fir forests in western Oregon*.* Biological Science Report
    USGS/BRD-2002-0006, US Geological Survey, Forest and Range Ecosystem
    Science Center, Corvallis OR.

5.  Poage, N. J., and J. C. Tappeiner. 2002. Long-term patterns of
    diameter and basal area growth of old-growth Douglas-fir trees in
    western Oregon. Canadian Journal of Forest Research 32:1232-1243.

6.  Poage, N. J. and J. C. Tappeiner. 2005. Tree species and size
    structure of old-growth Douglas-fir forests in central western
    Oregon. *Forest Ecology and Management 204:329-343*

7.  Sensenig, T. 2002. Development, Fire History, and Current and Past
    Growth Rates of Old-growth and Young-growth Forest Stands in the
    Cascade, Siskiyou, and Mid-coast Mountains of Southwestern Oregon*.*
    Ph.D. dissertation, Department of *Forest Science*, Oregon State
    University, Corvallis OR.

8.  Spies, TA, and J. F. Franklin. 1991. The structure of natural young
    and old-growth forests in Oregon and Washington. Pp. 91-109 in LF
    Ruggiero, KB Aubrey, AB Carey, and MH Huff, technical contributors,
    *Wildlife and Vegetation of Unmanaged Douglas-fir Forests.* General
    Technical Report PNW-GTR-285, USDA Forest Service Pacific Northwest
    Research Station, Portland OR.

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## Tappeiner, J. C., D. Huffman, D. Marshall, T. A. Spies, and J. D.. Bailey. 1997. Density, ages and growth rates in old-growth and young-growth forests in coastal Oregon. *Canadian Journal of Forest Research* 27:638-648. {#tappeiner-j.-c.-d.-huffman-d.-marshall-t.-a.-spies-and-j.-d..-bailey.-1997.-density-ages-and-growth-rates-in-old-growth-and-young-growth-forests-in-coastal-oregon.-canadian-journal-of-forest-research-27638-648. .AdvGuide-2}

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## Tappeiner, J.C., D.A Maguire, and T.B. Harrington. 2007. Silviculture and Ecology of Western U.S. Forests. Oregon State University Press, Corvallis, OR, 440p. {#tappeiner-j.c.-d.a-maguire-and-t.b.-harrington.-2007.-silviculture-and-ecology-of-western-u.s.-forests.-oregon-state-university-press-corvallis-or-440p. .AdvGuide-2}

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