Soils Management, Site Productivity and Forest Nutrition: Nutrient Balance
and Availability in the Soil and the Plant
Rob Harrison, School of Forest Resources
University of Washington
1) principals2) strategies3) implementation
Sustainable Soil Management:
- maintenance of fertility- avoiding loss from physical disturbance- other potential factors
Principles:
- models for sustainable soil management
Strategies:
Examples of adaptive management models used for achieving sustainable forest management (Burger etal 2008).
Components of an adaptive management model (Burger et al. 2008, Heninger et al. 1998).
- Weyerhaeuser NR model
Implementation:
Weyerhaeuser soil disturbance classification system for Western Timberlands
Weyerhaeuser Soil Disturbance ClassificationExample of Class 1 Soil Disturbance
Weyerhaeuser Soil Disturbance ClassificationExample of Class 2 Soil Disturbance
Weyerhaeuser Soil Disturbance ClassificationExample of Class 3 Soil Disturbance
Weyerhaeuser Soil Disturbance ClassificationExample of Class 4 Soil Disturbance
Soil Disturbance Assessment ProceduresIdentifying a change in soil disturbance class and measuring length of the disturbance
Soil Management Process
Report Copy - Cover Page
Soil Disturbance from Ground-Logging Declined After Soil Management Process Implementation
- Nutrient balance and management
Implementation:
View of biomass-removal treatments at the Fall River research area: commercial bole-only removal (top left), commercialbole up to 5-cm top removal (top right), total-tree removal (bottom left), and total-tree-plus removal (bottom right) (Ares et al. 2007.
loss after harvest 4.1% 3.9% 6.2% 6.6%
Aboveground dry weight of Douglas-fir trees and competing vegetation, at plantation age five years, without (-VC) and with (+VC) annual vegetation control at three sites.
Scotch Broom at Matlock.
No veg control.
veg control.
bioenergy removals will likely remove biomass with higher nutrient concentrations
- amelioration of (potential) problems
Implementation:
BO
BO+compact
Age 5Fall RiverLTSPgrowth
volu
me
inde
x (d
2*h)
- amelioration of (potential) problems- enhancement of productivity
Implementation:
Installations of the PNW Stand Management Cooperative
SILVICULTUREWOOD QUALITY
NUTRITION
MODELING
College of Forest Resources University of Washington Box 352100 Seattle Washington 98195-2100 206-543-5355 phone 206-685-3091 fax
Percent Difference in Volume Increment vs Total Nitrogen Fertilizer Applied
0
10
20
30
40
50
60
70
200 400 600 800 1000
Total N Fertilizer Applied (lb/ac)
IIIIIIVV
Site Class:II : 120-140 ftIII : 100-120 ftIV: 80-100 ftV : < 80 ft
Overall results of SMC studies Response vs. N rate. Sidell thesis.
(1)
Table 3. Effect of Prior Fertilization on Seedling Volume Index Growth.
App. yr since Vol-ind Vol-ind % Vol-indInstall. Name Rate planting Control +N Difference
- lbN/ac- –– y ––––– index only ––– –– % ––17 Little Ohop Creek 1000 5 5.12 7.35 1653 Camp Grisdale 1000 5 2.12 2.61 1053 Camp Grisdale 400 5 2.12 2.15 16
134 Pack Forest 1000 7 3.36 6.24 22156 Coyle 1000 5 2.79 5.05 17167 Hanks Lake 1000 6 1.58 3.40 11167 Hanks Lake 400 6 1.58 4.03 25168 Simpson Log Yard 1000 6 1.75 2.69 8168 Simpson Log Yard 800 6 1.75 2.37 11168 Simpson Log Yard 200 6 1.75 1.32 -1177 Pack Forest Lookout 1000 6 2.70 2.50 13177 Pack Forest Lookout 800 6 2.70 3.98 28
Average 15prob = 0.0017
Volume index is not an actual volume, as it is calculated as diameter squared times the height…thus it is useful for comparison only.
SMC carryover study results 5-7 years of growth
Results of RFNRP studies
1) N response averaging 20% (unthinned) -30% (thinned) with 400 kgN, highly site dependent.
2) Clearly, both response to N and other nutrients is site controlled. Indicates need for larger scale studies on a wide variety of sites to pin response to site variables.
3) Effects of N fertilization appear to be very long-lived.
SMC (1991+)No multi-element additions. SMC
Type II, III and IV no fertilizer work at all
SMC Type I Installations-plantations with initial stocking 300-680 spa-Respace (PCT) before onset of competition
-7 core treatments (basic 7)ISPA, ISPA/2, ISPA/4, ISPA and ISPA/2 min thinISPA repeated thinISPA heavy thin
2-8 plots for other work, including fertilization
Eric Sucre did his M.S. on 7 fertilized sites
Location of SMC Type 1 Fertilized Research Installations
Site Descriptives
Soil & Site Properties Examined
• Climatic data• Elevation• % Slope• Relative Density (RD)• Quadratic Mean Diameter (QMD)• Site Index (SI)• bulk density (Db) • pH • C:N ratio • cation exchange capacity (CEC)*• Inorganic nitrogen (NO3- and NH4+)*
*Mineral Soil only
Total volume and 4-year PAI relative response for each treatment regime at the respected treatment intervals (224 kg ha-1 of N as urea every 4 years). Standard errors are shown.
Multiple regression equations for the relationships between the unstandardized residuals of total volume (m3 ha-1) and 4-year PAI (m3 ha-1 yr-1) response to 224 kg N ha-1 as urea (dependent variables) and various soil, site and stand variables (independent variables).
Results of SMC studiestoo few sites (7) for broad generalizations
1) Response to N is site and stand controlled. Indicates need to couple fertilization with other silvicultural treatments, particularly stocking, and use RD or other stand properties to drive time of fertilization.
SMC Type V (paired-tree)
- new N fertilization studies based on a Weyerhaeuser NR design- also used in CIPS "beyond N" study
Objectives
• Test soil variables including bulk density, nutrient pools, temperature, and moisture
• Record non-soil variables such as site index, LAI, elevation, slope, precipitation, air temperature, and relative humidity
• Determine which factors can predict N fertilizer response
• Focus on variables that are easily obtained
Paired Tree Installations
Center for Advanced Forestry Systems 2010 Meeting
� RedMarkers – Glacial parent material
� GreenMarkers –Sedimentary parent material
� BlueMarkers – Igneous parent material
Soil Nitrogen to 1 Meter
Center for Advanced Forestry Systems 2010 Meeting
Glacial Sedimentary
Growth results from SMC Type V studies
ConclusionsGood soil management includes knowing what is there and making sure it is not degraded with a future loss in productivity. This includes all soil properties that might affect productivity.
However, in some cases avoiding a practice that may degrade a site may be more expensive than ameliorating the site back to its original productivity.
Management treatments can also enhance natural soil productivity.
We still have a lot to learn!!!
