Q&A: Thinning and Roads
1. Doesn’t everyone agree that commercial thinning is great?
Quick Answer:
Commercial thinning—logging half to two thirds of the trees in a given stand to
grow bigger trees faster—is widely touted as a “win-win” solution, but there are
many scientific studies questioning the ecological tradeoffs.
Most studies
agree that the practice of thinning is too new to understand its long term
implications, but there are many known adverse impacts.
In-depth Answer:
The science and implementation of restoration treatments in young-managed
forest landscapes is in its infancy. As recognized by the Pacific Northwest
Forest Restoration Learning Network, there are few long-term studies which
help managers clearly identify "best management practices" for thinning
projects.1 In fact, a common debate is whether forests should be actively
restored (e.g., thinned) and how management of road systems interact with
thinning to affect ecosystem recovery at watershed and landscape scales.2
A team of scientists recently considered large scale thinning and identified
many concerns about the practice. They found that even when confined to
previously harvested stands, thinning treatments must be evaluated carefully
and implemented in such a way as to avoid negative impacts.3 Ground based
methods and associated machine piling, burning of activity fuels, construction
and increased use of roads and landings can increase soil erosion, compact
soils, and elevate surface runoff.4
They concluded that there was no support for the contention that an extensive
thinning program hastens restoration of historic patterns of forest
Davis, L. Restoration of Young Forests with an Emphasis on Pre-Commercial Thinning.
Pacific Northwest Forest Restoration Cooperative – Technical Paper No. 1, August, 2008
2 Id.
3 Carroll, C., Odion, D., Frissell, C, Dellasala, D. Noon, B., & Noss, R., 2009. Conservation
Implications of Coarse Scale versus Fine Scale Management of Forest Ecosystems: Are
Reserves Still Relevant? Klamath Center for Conservation Research, Orleans, CA.
4 Id.
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heterogeneity on a landscape scale, and that thinning should not be considered
a cure-all for forests degraded by fire exclusion or other human activities.5
Another recent study on thinning riparian areas concluded that passive
management (letting the forest self-thin) may often be the treatment that will
best enhance biological diversity in degraded riparian forests.6
2. Aren’t these plantations “overstocked” and unhealthy?
According to ecological research, the density of so-called “overstocked” forest
areas is consistent with forest areas that are naturally regrowing after large
natural disturbances (such as fires, disease, etc.).7 If left “unthinned,” these
dense areas would effectively thin themselves, with weaker trees dying off,
which in turn create a diverse habitat of standing snags and fallen logs—in
short, a healthy, thriving forest.8 In contrast, thinning projects actively remove
future dead wood from remaining on the landscape.
3. Doesn’t thinning help the forest by growing bigger trees faster, and
moving it toward “late-seral” conditions sooner?
The Forest Service focuses its discussions about forest health on growing
bigger trees faster, but healthy soil is perhaps the most important factor of
growing and sustaining late-successional forests over time.9
While thinning has been shown to increase tree diameter by a few inches over
multiple decades, this is primarily beneficial if the forest is being managed for
future timber production. As noted immediately above, dense Douglas Fir
forests naturally enter into the “stem-exclusion” phase, where completion, in
the form of disease, bugs and other natural causes kills the weaker trees, and
the stronger trees continue to grow.
Commercial thinning removes most of the trees that would die naturally in the
stem exclusion phase, leading to decreased standing and down dead trees –
both are essential for biodiversity. Studies show that in one hundred years, live
Id.
Pollock, M. and Beechie, T., 2014. Does Riparian Forest Restoration Thinning Enhance
Biodiversity? The Ecological Importance of Large Wood. Journal of the American Water
Resources Association (JAWRA) 50(3): 543-559.
7 Franklin, J. & Dryness, 1973, Natural Vegetation of Oregon and Washington, Pacific
Northwest Forest and Range Experiment Station, USDA Technical Report.
8 Pollock, M., et. al., 549.
9 Beschta R.L., Rhodes, J.J., Kauffman, J.B., Gresswell, R.E., Minshall, G.W., Karr, J.R., Perry,
D.A., Hauer, F.R., Frissell, C.A., 2004. Postfire management on forested public lands of the
Western USA. Conservation Biology, 18: 957-967.
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tree, snag and down wood biomass will be highest in unthinned stands and
lowest in the highest-intensity thins.10
One of the most effective, efficient and important ways to restore degraded soil
productivity is to retain all sources of large woody debris and organic matter
and prevent additional soil disturbances in degraded areas.11
4. Doesn’t thinning benefit riparian areas?
A recently published peer-reviewed study by two research scientists from the
National Oceanic and Atmospheric Administration (NOAA) directly addressed
the question of whether commercial thinning enhanced, or retarded, attaining
riparian biodiversity.12
This study looked in-depth at the current peer-reviewed science focused on the
impact of thinning in riparian areas in regrowing Douglas-Fir forests in western
Oregon. The rationale for commercial thinning is that it should increase the
growth rates of the remaining trees and thus more rapidly develop a forest of
large diameter trees. However, the key driver creating biologically diverse
forested riparian ecosystems is not large live trees, rather it is a steady supply
of large deadwood.13
The scientists found that not thinning produced substantially more deadwood
across a wide range of sizes useful to a variety of vertebrate species. They
concluded that passive management may often be the treatment that will best
enhance biological diversity in degraded riparian forests, and that thinning in
riparian areas should generally be limited to situations where large deadwood
is already abundant (which does not include most second-growth forests).14
5. Don’t the “gaps” in thinning projects increase browse for elk?
Creating small clearcuts to increase browse for elk is discredited in scientific
literature. Biomass of edible browse in clearcuts is often less than that of grass
in meadows and is therefore not actively sought out for foraging.15 Browse that
grows in late-successional forests, by contrast, has lower tannin levels and
Spies, T., Pollock, M., Reeves, G., and Beechie, T., Effects of Riparian Thinning on Wood
Recruitment: A Scientific Synthesis , Science Review Team Wood Recruitment Subgroup, Jan.
2013
11 Beschta, et. al, 2004.
12 Pollock, Michael M. and Timothy J. Beechie, 2014. Does Riparian Forest Restoration
Thinning Enhance Biodiversity? The Ecological Importance of Large Wood. Journal of the
American Water Resources Association (JAWRA) 50(3): 543-559.
13 Id.
14 Id.
15 Weckerly FW. 2005. Grass and Supplemental Patch Selection by a Population of Roosevelt
Elk. Journal of Mammalogy, 86(3); 630-638.
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greater amounts of leaves, succulence, and proteins than members of the same
species found in clear cuts.16 In addition, elk avoid contact with areas
associated with human traffic such as recently used forest access and logging
roads and main throughways, and preferentially seek out areas with increased
topographic complexity and distance from open roads.17
6. Doesn’t thinning open up the forest canopy and increase plant
diversity?
Thinning does increase plant diversity, but unfortunately, that often comes in
the form of increased spread of invasive species. The roads, skid trails and
open canopy associated with thinning all provide channels for spreading
species such as Canada thistle, bull thistle, Scotch broom, St. John’s Wort,
and tansy ragwort.18 Invasive plants can reduce biological diversity, displace
native plant communities, decrease and degrade wildlife habitat, alter fire
regimes, change hydrology, disrupt mycorrhizal associations, alter nutrient
dynamics, and increase soil erosion.19
7. Don’t we need timber jobs to help rural economies?
Increased logging on federal lands will not fix the economic problems in rural
counties. For example, a recent increase in logging by 75% in Lane County did
not result in a corresponding increase in jobs.20 Increased logging is actually
at odds with job creation in one of Oregon's fastest growing industries, outdoor
recreation. The outdoor recreation industry employs about 140,000 workers in
Oregon (logging and wood-products manufacturing employ fewer than
30,000).21
Restoration jobs are also an important economic component of rural
economies.
A total of $411.4 million was invested in 6,740 watershed
restoration projects throughout the state of Oregon from 2001 to 2010,
resulting in the generation of between $752.4 million and $977.5 million in
economic output and 4,628 to 6,483 jobs.22 The jobs created by restoration
activities are located mostly in rural areas, in communities hard hit by the
economic downturn. Restoration activities bring a range of employment
opportunities for people in construction, engineering, natural resource
sciences, and other fields. Unlike in other economic sectors, restoration jobs
Id.
Long RA, Rachlow JL, Kie JG. 2008. Effects of Season and Scale on Response of Elk and
Mule Deer to Habitat Manipulation. Journal of Wildlife Management, 72(5); 1133-1142.
18 USFS, 2012, Preliminary Assessment, Jazz Thinning, at 142.
19 Id.
20 Rob Handy, Eugene Register Guard, July 6, 2014.
21 Ernie Neimi & John Kober, The Oregonian, June 29, 2014.
22 Kellon, C. and Hesselgrave, T., 2014. Oregon’s Restoration Economy: How investing in
natural assets benefits communities and the regional economy. Sapiens: Vol. 7.
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can’t be outsourced to distant locations, so these dollars tend to stay in the
local and state economy.23 Restoration investments also continue to accrue and
pay out over time. Long-term improvements in habitat create enduring
benefits, from enhanced recreational and fishing opportunities to the provision
of critical ecosystem services.
8. Aren’t the roads already there?
rebuilding them?
What is the big deal about
The Forest Service suggests that rebuilding roads on existing alignments has
no significant impact because the roads once existed on the landscape.
Although in different stages of recovery, every road segment that is rebuilt will
degrade hydrologic function, and lose the years of the recovery it has had.
The act of road construction is by far the greatest contributor of sediment to
aquatic habitats of any management activity.24 Even temporary road
construction can cause resource damage including erosion and sedimentation,
exotic species spread and disruption of wildlife.25 Unpaved roads and stream
crossings are the major source of erosion from forest lands contributing up to
90% of the total sediment production from forestry operations.
In addition to construction and reconstruction impacts, using the roads for log
haul greatly elevates erosion and sediment delivery. Research documented that
roads used by more than four logging trucks per day generated more than seven
times the sediment generated from roads with less use, and more than 100
times the sediment from abandoned roads.26 Even with a road surface of
crushed rock aggregate, elevated truck traffic increased sediment production
by 2 to 25 times that on unused roads in western Oregon.27
9. As far as road decommissioning to create jobs, isn't it a self-limiting
enterprise? Once all the roads are decommissioned or repaired then
what is this new job force going to do?
The national average for decommissioning Forest Service roads is $2,803 per
mile. A recent University of Oregon study found that every $1 million invested
Id.
Meehan, W.R. (ed.), 1991. Influences of Forest and Rangeland Management on Salmonid
Fishes and Their Habitats. Am. Fish. Soc. Special Publication 19.
25 Trombulak, S.C., and C.A. Frissell. 2000. Review of ecological effects of roads on terrestrial
and aquatic communities. Conservation Biology 14: 18-30.
26 Reid, L.M., Dunne, T., and C.J. Cederholm, 1981. Application of sediment budget studies to
the evaluation of logging road impact. J. Hydrol (NZ), 29: 49-62.
27 Foltz, R.B. and Burroughs, E.R., Jr. 1990. Sediment production from forest roads with wheel
ruts. In: Proceedings from Watershed Planning and Analysis in Action. Symposium Proceedings
of IR Conference, Watershed Mgt, IR Div, American Society of Civil Engineers, Durango, CO,
July 9-11, 1990. pp. 266-275.
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in watershed restoration resulted in 15-24 jobs. Using the median of 20 jobs
per million dollars as a starting place, if the MHNF chose to meet its target of
decommissioning 49% of its roads,28 it would result in over 80 jobs created primarily for heavy equipment operators and restoration specialists.
Also, there are ongoing road maintenance needs that are not reflected in this
figure, and do not have a fixed end. The Mt. Hood National Forest now has a
backlog of $51.8 million in deferred road maintenance. There is ample road
maintenance to be done over the long term; after the Forest Service
decommissioned 49% of the roads, there would still be ~1,500 miles of road to
maintain in better condition than most are currently.
10.
But if we remove roads, won’t that limit access to recreation?
Road decommissioning actually benefits local economies through increased
tourism and recreation. The removal of disused logging roads allows road
maintenance funding to target roads which receive the highest public use.
Along with improved access to recreational areas, many roads can be converted
into trails, adding hundreds of miles of new areas for visitors to explore.
11.
Is there any logging that Bark supports?
Logging already has enough advocates.
Profit-driven resource extraction
projects cause harm to our environment, while limiting our perception of a
forest’s value to the lumber we can extract from it instead of the high quality
air, water, wildlife, and recreation that it can sustain.
Bark is focused on
advocating for forest management that promotes healthy, thriving forests for all
living things.
28
Mt. Hood National Forest, 1999 Access and Travel Management Plan.