Douglasfir SoilPlant Water Relationships: Tree and Landscape Scales

1
Douglas-fir Soil-Plant Water Relationships
Tree and Landscape Scales
Soil and water the foundation of it
all National Woodlands, Autumn 2007

• Northwest Forest Soils Council Meeting Jan. 29,
  2008

2
Douglas-fir Soil-Plant Water Relationships
Tree and Landscape Scales

• Technical Session Theme Background

• Moisture supply is a critical factor influencing
  Douglas-fir productivity in the Pacific Northwest
• Significantly influenced by
• Soil physical properties (including organic
  matter)
• Varied soil moisture holding capacity
• Climate
• Typical dry summers
• Ongoing climate changes
• Topography
• Aspect
• Slope percent
• Landform position
• Stand and competing vegetation conditions

3
Douglas-fir Soil-Plant Water Relationships
Tree and Landscape Scales

• Technical Session Theme Background

• Previous technical sessions have not focused on
  this topic
• Emphasis in the past on soil disturbance (organic
  matter removals / compaction / puddling) and
  nitrogen limitations
• Increasing interest in
• understanding the mechanisms of treatment
  response
• productivity potential modeling
• Concerns about water use and water yields
• Concerns about changing climate
• Considerable new work in this area