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Impacts of MPB on hydrology & vegetative development: Phase II

Ellen MacDonald, Uldis Silins, Axel Anderson, & Mark Poesch


Impacts of MPB on hydrology & vegetative development: Phase I Vegetation / hydrology tightly coupled Focus on processes driving change - micro-climate (light regime, wind, evap demand) - water cycling (P, evap, soil moisture, groundwater) - understory veg dynamics) ** enables broader scaling / modeling effects

 Issue of “control”; simulate MPB attack – variable density herbicide treatment    

Control (untreated) Simulated MPB attack (50% overstory kill) Simulated MPB attack (100% overstory kill) Clearcut - harvested to simulate “salvage logging” management


Impacts of MPB on hydrology & vegetative development: Phase I Hydrology

4 treatments 2.2 ha (each)

2 additional treatment replications 1.2 ha (each)

Green attack

Red attack

Phase I of study

Pure pine ~ 120 yrs

Medium site index

22-24 m height

Grey attack

Vegetation response • replicated


Hydrology Stand water use Interception (canopy/forest floor) • 70% growing season P • No effect of green-red attack

Transpiration • 20% growing season P • Mix of chlorotic/fading & dead • 100% MPB treatment – Stand T 50% lower • 50% MPB treatment – Stand T 10% greater

Soil/groundwater • •

Soil water - up to 30% increase but restricted to surface 20-40 cm No groundwater response (evap processes still dominate)

Scaling (modeled across range of Alberta climates) • • •

Partial red attack (10 mm (50%) over growing season) Massive red attack (51 mm (255%) over growing season) Grey attack (107 mm (535%) over growing season)

Vegetation • • •

Small increases in species richness & cover No change in soil nutrients or microbial communities Poor pine regeneration (seed) – microsite limitations


Impacts of MPB on hydrology & vegetative development: Timeline Phase I • Fall 2007 – May 2008: set up & instrument sites • June 2008 – 2009: pre-treatment measurements • June 2009: treatment application • June 2009 – 2010: 1st post-treatment yr measurements • June 2010 – 2011: 2nd post-treatment yr measurements

Site monitoring (2012/2013) • Transition to fully developed grey attack

Phase II • Grey attack measurements (2014-2017)

 Grey attack will likely force greatest environmental change  

Hydrology – stand water cycling, recharge & generated runoff Establish trajectory of vegetation responses, stand re-development


Impacts of MPB on hydrology & vegetative development: Phase II Phase II • D in micro-climate drivers, interception, soil/groundwater dynamics • Understory light regimes, tree regen, understory veg dynamics

Green attack

Red attack

Grey attack

 Full sequence of effects (micro-climate, water cycling, understory vegetation dynamics  Process-focus research enables broad scaling-extension of insights

Phase II – linkage w/ fRI Water Program • Impacts on surface waters, developing provincial decision support systems


Impacts of MPB on hydrology & vegetative development: Phase II Phase II – linkage w/ fRI Water Program

11uldissilins  

https://foothillsri.ca/sites/default/files/11UldisSilins.pdf