Northwest Forest Soils Council Winter 2005 Meeting

January 28, 2005

Vancouver, WA regional office;
Gifford Pinchot National Forest Forest Headquarters
10600 N.E. 51st Circle,
Vancouver, WA 98682;
phone 360-891-5000

We have the Goat Rocks, Indian Heaven and Mt. Adams rooms reserved. There is no registration fee for this workshop

download schedule in MS Word - maps from Corvallis, OR - maps from Canada, Seattle

Workshop: Predicting Response to Forest Fertilization

8:00     Building Opens

8:00 - 8:25     Registration, Coffee, snacks

8:25    Welcome (Rob Harrison)

8:30 - 12:15    Workshop on Predicting Response to Forest Fertilization

8:30    Bob Edmonds, UW. Predicting response to forest fertilization using site information.

9:00    Keith Jayawickrama. OSU. "Genetics and soils: The potential for boosting genetic gains by understanding and reducing soil variability; genetic gains and site productivity.

9:30    Doug Maguire. OSU. Site/nutrition/fertilization effects on Swiss Needle Cast.

10:00    Break

10:30    Eric Turnblom & Eric Sucre. UW. Using SMC site/response studies to predict response to fertilization in coastal stands.

11:00    Dick Waring and Joe Landsberg. OSU & UBC. Implications of altering soil fertility and genetic selection on growth responses assessed with the 3PG model across the PNW.

11:30    Moderated discussion with an eye to what we know and what do we need to know?  

12:15    Lunch. Make your own sandwich, salad and drinks. Continue discussion on a fuller stomach.

12:30    Start poster session

Poster titles (so far)

Rob Brockley, BC Ministry of Forests, Kalamalka Research Station.  Effects of intensive fertilization on the foliar nutrition and growth of
young lodgepole pine and spruce forests in the interior of British Columbia, Canada.

Shannon M. Berch, Rob Brockley, Jeff Battigelli, Shannon Hagerman, and Brian Holl. BC Ministry
of Forests and consultants. Impacts of fertilization on components of the soil biota under young
lodgepole pine stands in the interior of British Columbia.

2:00    Business meeting

Adjourn by 3:30

Abstracts of Presentations Submitted So Far

Bob Edmonds, 2005. Predicting response to forest fertilization using site information. Edmonds, Robert L. College of Forest Resources, University of Washington, Seattle, WA 98195
Prediction of tree growth response to forest fertilization has been the objective of many studies.  Response has been related to foliar N, P and S, various soil N indices, including mineralizable N, and extractable soil P.  Consistently accurate prediction of response has proven to be difficult, particularly in the Pacific Northwest.  In order to obtain a wide data base on the response of Douglas-fir to urea-N fertilization in western Oregon and Washington, the Regional Forest Nutrition Project (RFNRP) was initiated in 1967.  Analysis of RFNRP data across the region showed that while some sites showed high response others did not.  This is generally not satisfactory for forest managers since stand specific prediction of response is desired.  They want to know that their investment in fertilizer application will result in growth increases. Site information can be used to obtain stand specific predictions.  RFNRP response data (relative difference in volume growth between fertilized and control plots 4 years after fertilization with 448 kg N/ha) from plots established from 1969 to 1972, was regressed against 28 stand and site variables (e.g., site index, age, elevation, age, soil and forest floor C/N ratio, soil cation concentrations, etc.) using stepwise regression. Stand were naturally regenerated and ages ranged from 16 to 79 years. Data from 120 installations were stratified by thinning level (thinned or unthinned), geographic location (provinces), and site quality.  Forest floor C/N ratio was the dominant variable related to response.  Response was best predicted in high site quality stands (60% of the variation wwas explained by forest floor C/N ratio, and 75% of the variation was explained by inclusion of surface soil exchangeable K).  The forest floor very is responsive to fertilization additions.  Similar analyses need to be conducted in planted young Douglas-fir stands to predict response.

Dick Waring and Joe Landsberg, 2005. Implications of altering soil fertility and genetic selection on growth responses assessed with the 3PG model across the PNW.
It is well established that stand growth can be increased, even under a stressful climate, by increasing nutrient availability. Physiologically-based models, such as 3PG, explain such responses by predicting an increase in both photosynthetic capacity and the proportion of growth allocated above-ground. We demonstrate how the model can be used to explore the probable effects of improved nutrition and breeding strategies on growth. Field experiments designed to test these and other specific predictions are encouraged to aid in tailoring management strategies that combine genetic selection with judicious applications of soil amendments. 


Abstracts of Posters Submitted So Far

Adams, A.B., 2005. Red Alder Leaf Characteristics and Their Interrelationship to Nutrition, Soil Moisture and Grazing by Phytophagous Insects with Emphasis on Tent Caterpillars. University of Washington.
Red alders have leaves that provide a palatable food resource for many phytophagous (leaf eating) insects.  Upon close inspection, we determined that intraspecific variation in alder leaf phenolics, nitrogen, relative water content, texture and other attributes are high.  We also determined that these variables are correlated with the health and reproductive success of the leaf-eating insects.  Of these herbivores, tent caterpillars especially interesting because they have the capacity to completely defoliate broadleaf deciduous trees such as red alder.  Red alder trees respond to this defoliation by producing less palatable leaves with symptoms of nitrogen deficiency and an increase in leaf phenolics.. These same symptoms occur with leaves of red alders whose roots are in anaerobic soil environments. Defoliation rarely results in tree death; however, in some cases a stand can suffer more than 50% leaf defoliation.  Alders respond to such large-scale leaf loss (provided the weather is favorable) by producing new leaves as late into the growing season as the end of August.  A variety of control mechanisms usually result in a rapid decline in phytophagous insect populations allowing for high tree survival rates; nonetheless, the massive loss of foliage does have an impact on the quality and quantity of wood produced.  In this presentation we will discuss methods for determining stand susceptibility to insect outbreaks and possible management scenarios for control of phytophagous insects on red alder.  Investigative techniques for potential stand herbivore susceptibility range from such methods as using leaf infrared reflectance to estimate leaf nitrogen content to simple field reconnaissance in which census can be done on parasitoid and viral infection rates.  Any application of spray needs to be done in synchrony with the target organisms’ most sensitive life history phase.  In some cases, weather conditions prior to, during and/or after application can influence the effectiveness of the various control methods.  Cyclic phytophagous insect outbreaks can even act as a natural method of stand thinning.  Management responses to damage from herbivores depend on the severity and timing of the problem as well as the stand management objectives.

Kyle Peterson, 2005. Biomass and nutrient pool estimates for a 46-year, mixed Douglas-fir and Western hemlock stand on a high index site in SW Washington. Kyle Petersen, Christopher Licata, Brian Strahm, Barry Flaming, Rob Harrison. University of Washington, College of Forest Resources, Box 352100 Seattle, WA 98195-2100; Tom Terry' Weyerhaeuser Company P.O. Box 420, Centralia, WA 98531; contact e-mail address: ksp3@u.washington.edu
The Fall River Long-term Productivity Study was initiated in 1998 to examine the implications of various soil disturbance, vegetation management, and harvesting/organic matter retention practices on soil processes and long-term Douglas-fir growth.  The site was harvested in 1999, and the dry biomass and nutrient content of the preharvest system components were estimated for both Douglas-fir and western hemlock.  Development of local tree biomass equations demonstrated a 14 percent discrepancy between the Fall-River site-specific estimate of above-ground biomass for both species and the commonly used, generalized Gholz biomass equations.  The Gholz biomass equations overestimated the stand biomass. Estimated preharvest C and N pools reflect the relatively high productivity potential of the Fall River site.  The site index is 41-43 m breast-height at age 50 years (King 1966).  The Boistfort soil series, an Andisol, contained ~250000 kg C/ha and ~13000 kg N/ha to a depth of 80 cm.  As expected of higher-quality forest soils in the Pacific Northwest, the majority of the nitrogen pool was located in the soil at the time of harvest.  The standing crop plus understory vegetation represented a relatively small portion of the total N pooled at the site.  The ratio of N contained in all living and dead above-ground plant material to the N contained in the soil to 80 cm depth is ~.10. 

Brian Strahm, 2005. Nitrate Sorption in a Variable-Charge Soil of the Pacific Northwest. Brian D. Strahm * and Robert B. Harrison. Few studies have investigated the potential of physicochemical mechanisms to retain nitrate (NO3-), particularly in the Pacific Northwestern US.  The specific objectives of this study are to:  (i) determine the capacity of different horizons of a mesic, Typic Fulvudand under intensive forest management in southwestern Washington to sorb NO3-, (ii) determine the point of zero net charge (PZNC) for each horizon of this soil, and (iii) relate specific mineralogical characteristics to the aforementioned physicochemical soil properties.  Five soil pits were excavated to a depth of approximately 150 cm, and soil samples were composited by genetic horizon, including A, AB, 2Bw1 and 2Bw2 horizons.  Through batch equilibration, NO3- sorption isotherms were created for each horizon, indicating an increase in sorption with both depth and increased NO3- solution concentrations.  The PZNC of the 2 Bw horizons was determined to exist between a pH range of 3.5-3.6.  Selective dissolution techniques of the mineral soil were employed to determine the presence of short-range-order aluminosilicates, and to associate Al/Si ratios with the physicochemical behavior of mineral soil matrix.  Based upon average NO3- solution concentrations over a three-year period, these soils exhibit the capacity to retain a significant proportion of NO3-, relative to the observed leaching rates at a depth of 100 cm.

Eric Sucre, 2005.  Estimating Response of Douglas-fir to Urea in Western Oregon and Washington. E.B. Sucre, R.B. Harrison, E.C. Turnblom, and D.G. Briggs. Estimating the amount of response of Douglas-fir [ Psudotsuga menziesii (Mirb.)] stands from N fertilization is extremely difficult due to the high variability that exists between sites.  Our objective was to determine how various site (site index, age, relative density and total precipitation) and soil variables (total N, soil cation exchange capacity, available N, bulk density, pH, and C/N ratio) influence stand response to multiple applications of 224 kg N ha-1 as urea.  Composite samples of the forest floor and 3 depths of mineral soil (0-15cm, 15-30cm, and 30-50cm) for 6 fertilized Stand Management Cooperative (SMC) Douglas-fir stands located in western Washington and Oregon were used to quantify soil variables. The response variable (relative difference in volume growth between fertilized and control plots) was regressed against site and soil variables. The data were stratified by 3 different stocking levels [ISPA (initial stems per acre), ISPA/2, and ISPA/4).